ELECTRICAL PANELBOARD – A COMPLETE GUIDE

Also referred to as distribution board, an electrical panelboard is used to distribute electrical energy to various parts of a residential or commercial facility. Its role in an electrical distribution system is very similar to that of a router in a typical networking system. Basically, it divides electrical power into different branches so that every part of the house can be powered by electrical energy. Every branch has a fuse or circuit that offers protection from overload, over-current, and short-circuit. It is impossible to access a panelboard from the back this is basically they are usually mounted to the wall. In addition, there will be no control over the light and power circuits in a facility if a panelboard is not installed. Panelboards

Is there any difference between a panelboard and a switchboard?

The role played by a switchboard and a panelboard in a power distribution system are very similar. The major difference is in the way they are mounted or positioned. While panelboards are typically mounted on a surface, switchboards are capable of standing in an erect position. A panelboard can permit up to 1200A of electric current while a switchboard may only permit up to 5000A of current electricity.

Is there a difference between a loadcenter and a panelboard?

The similarity in functionality between a panelboard and loadcenter is so much that it is very difficult to dichotomize between them. In some part of the world, people refer to a smaller version of a panelboard as a loadcenter. A loadcenter is not designed to accept all types of circuit breakers. If it is not a plug-in breaker, it cannot be used on a panelboard. On the other hand, a panelboard can accept different types of circuit breakers whether it is a plug-in circuit breaker or bolt-on circuit breaker. As said earlier, panelboards can accept electric current up to 1200A. This magnitude of current is too much for a loadcenter to handle and as such, loadcenters are usually limited to a maximum current of 400A.

Is there a difference between lighting and appliance panelboard and a power panelboard?

While the lighting and appliance panelboard consists mainly of single-phase load, the power panelboard consists of three-phase loads irrespective of how it is connected.

What are General Purpose Panelboards?

A general purpose panelboard is a panelboard that offers more flexibility in its method of use. This type of panelboard is not restricted to a particular pattern of application. There are different types of special purpose panelboards.

  1. Branch circuit monitoring panelboard: This type of general purpose dashboard monitors the magnitude of incoming electrical power and that of all branches. It is used in commercial facilities to determine the amount to be paid by tenants or occupants of each room based on the number of load they have. It is also used in industries and data centres.
  • Column width panelboards: This type of general purpose panelboard is used in many warehouses. It has a good design that makes it fit between support columns. The dimension of a conventional column width panel board is 8.63’’ X 6.0’’. However, the value of the height may vary between 69” and 90”.
  • Fusible lighting panelboard: This one is used in industries and commercial places where abnormal current is very prevalent.
  • Lighting control panelboards: This is a multipurpose panelboard. It has the ability to provide protection from over-current. It is used when there is a need to ensure strict compliance to local energy codes.
  • Elevator control panelboards: This one has the ability to house a standard fire alarm system, an elevator control mechanism, and power distribution system. It can control and distribute electrical power to up to four different elevators at a time.

Also, there is another category of panelboard referred to as hazardous rated panelboards. This type of panelboard is designed for use in a locality where the atmospheric and environmental conditions are not great. If you reside in a place where vapour and dust is prevalent, the hazardous rated panelboard may be the best bet. Before investing in this type of panelboard, you must consider factors like the voltage rating and short-circuit rating. Hazardous rated panelboards are further subdivided into two. There is the factory sealed type and the non-factory sealed type.

Factors to consider before choosing a panelboard

Before choosing a panelboard, make sure you consider the following:

  1. The maximum amount of current that each branch circuit or feeder device permits.
  2. Voltage rating of the panelboard.
  3. The current rating of the mains.
  4. The short-circuit rating that is desired.

What makes up a panelboard enclosure?

A panelboard has three distinct components – the five-sided enclosure, chassis or inner part, as well as the trims.

The enclosure: This is the outer cover. It has a box shape. This is the part that is mounted to the wall and it is made from galvanized steel.

The chassis: This is usually joined to the main box by means of a screw. Also called the interior, it holds the circuits and fuses.

The trims: This is also called the front because it provides access to the main part of the panel board. It is usually a door that can be opened and close based on what is to be done. The trims or front usually has a lock that helps to prevent unauthorized access to the panelboard.

Apart from the aforementioned parts, a panelboard also has a filler plate which helps to cover or shield any space within the device that is not yet in use. In addition, all panelboards have a label that tells us more about the electrification specification and rating of the device. This gives the user of what to do and what not to do with the panelboard.

 The installation of a panelboard should be done by an expert. However, if you feel confident and know how to go about it, there is no problem. Otherwise, reach out to a certified electrical engineer.

WHAT ARE MINIATURE CIRCUIT BREAKERS?

What is a miniature circuit breaker and what does it do?

A miniature circuit breaker is an electromagnetic device that offers prevention and protection from current overflow. When it senses an overload or a magnitude of current that is beyond normal, it acts to automatically turn off the circuit or electrical enclosure. Before now, people use fuses a lot. However, due to a perceived inefficiency and a lack of cover from electrical faults and shocks, miniature circuit breakers have taken over.

A miniature circuit breaker opens when there is an overload or when the current exceeds the set threshold. However, it is designed to return to its default state automatically when the magnitude of current electricity normalizes. This is a major advantage as there are a few other circuit breakers that require manual reset. Typically, miniature circuit breakers have a low current rating.

How does a miniature circuit breaker work?

Just like a thermal circuit breaker, miniature circuit breakers use the principle of temperature difference in their operation. A typical miniature circuit breaker has a bimetallic strip. We know that constant flow of current brings about a rise in temperature of an electrical conductor. When excess current passes through, massive heat is generated and this raises the temperature of the bimetallic strip. As a consequence, the bimetallic strip will deflect to control a metal bar connected to it. It is the movement of this metal bar that brings about the opening and closing of the miniature circuit breaker for current control. This means that a miniature circuit breaker takes advantage of the thermal effect and properties of current electricity. This simple explanation is what guarantees the protection of your electronic appliances from faults that may be caused by unusual current delivery or power surge.

Usually, when a miniature circuit breaker develops a fault, it is replaced. This means it is a maintenance-free device. Its design is simple and sturdy and its case is usually moulded.

 It is not common to see people trying to repair a miniature circuit breaker. Miniature circuit breakers can be divided into Type B, Type C, and Type D based on the magnitude of electric current they are able to permit. While the Type B miniature circuit breaker is suitable for resistive inductive loads, the Type D is ideal for load with high inductive capability. The Type C miniature circuit breaker is in the middle because it is able to handle loads with a moderate inductive capacity.  Let’s take a look at some constructional parts of a miniature circuit breaker.

  1. The Frame: This is the outer shield of the miniature circuit breaker and it is usually a moulded component. It is strong, sturdy, firm, and rigid because it houses and covers other parts of the miniature circuit breaker.
  2. The trip unit: This is the part that acts when there is an upsurge in the magnitude of current electricity. This is the heart of the miniature circuit breaker, the main part. The major constituents of the trip unit are the bimetallic strip and electromagnet with each of them having a role to play.The bimetallic strip offers protection from excess current while the electromagnet takes care of short-circuits.

Let us take a more detailed look at the types of miniature circuit breakers we outlined earlier.

  1. Type B miniature circuit breaker: This type of circuit breaker is best suited for domestic use. It can also be used in commercial places if the load is not too much. The type B miniature circuit breaker has a tolerance of three times to five times its standard current rating and it is not ideal for massive loads as in an industrial setting.
  2. Type C miniature circuit breaker: The Type C miniature circuit breaker is an upgrade on the Type B miniature circuit breaker. While the Type B has allows electric current three times to five times its default rating to flow through it, the Type C has a tolerance of fives times to ten times which is an appreciable upgrade. One common area of application of a Type C miniature circuit breaker is in fluorescent lighting. This type of miniature circuit breaker can comfortable handle load with a moderate inductive capacity.
  3. Type D miniature circuit breaker: When the rate of flow of electric charges is very high, the Type D miniature circuit breaker is the most ideal. It has a minimum trip current rating of 10Ir and a maximum trip current rating of 20Ir. It is best suited for load with high inductive capability. In industries and production factories, this type of miniature circuit breaker is common. Equipments such as x-ray machines, welding machines, and UPS systems are typical examples of areas of application of Type D miniature circuit breakers.

How do I select the right miniature circuit breaker?

Selecting the appropriate miniature circuit breaker for a specific application requires carefulness and deliberateness. If not carefully done, the final aim of protection from abnormal current delivery will be compromised. Asides that, if the chosen circuit breaker is not equivalent to the requirement of the electrical enclosure or circuit, irregular tripping will occur.  

Furthermore, it is important to use the right type of miniature circuit breaker for the right purpose. For instance, using a Type B miniature circuit breaker for heavy duty equipments or an industrial purpose is highly inappropriate. In the same vein, it isn’t proper to use a Type D miniature circuit breaker for domestic or residential purposes since only small inductive loads are involved. It is also important to note the current carrying capacity of a circuit, wiring system, or electrical enclosure. Under no circumstance should the current rating of a miniature circuit breaker be greater than the maximum permissible current in a wiring system when it is not at full load. However, when all electrical appliances are fully operational and the wiring system is at full load, it is okay if the current rating of the miniature circuit breaker is higher or exactly equal in magnitude.

CIRCUIT BREAKERS: QUICK REVIEW OF THEIR LIFE EXPECTANCY

Why do I need a circuit breaker?

Electric shock and fire can happen anywhere and anytime. Home, office, bank, or cinema, electric shocks and fire can be triggered if the appropriate measures are not put in place. Electric appliances and equipment can expose you to electric hazard.

The damages caused are sometimes massive and irreversible especially when a part of the human body is affected. Some persons have suffered injuries and burns from electrical faults and these injuries will live with them for the rest of their lives. By simply investing in a circuit breaker, this situation can be arrested and effectively prevented. Just so you know, a circuit breaker is an electronic safety device. It is placed in an electrical circuit to control and manage the flow of electric current whenever an overload or a short-circuit occurs. It also helps to regulate the temperature of electronic appliances especially when it is rising continuously. In such scenario, the circuit breaker will automatically discontinue the flow of current through the circuit or electrical enclosure.

It is nearly impossible to do without the protection offered by circuit breakers in the world that we live in today especially if you consider that there are electronic appliances everywhere. Asides protecting these appliances from damage, a circuit breaker shield you and your family from electrical exposure that may arise from improper grounding, damaged insulation, voltage fluctuations, faulty wiring, and sort-circuit.

How long should a circuit breaker last?

The answer to this question is relative and it depends on a host of other factors like frequency of use, environmental factors and maintenance. However, it is estimated that under ideal conditions, a circuit breaker should serve for more than thirty years. It is advised that you replace any circuit breaker that has lasted for this long amount of time regardless of their working condition. Therefore, if a circuit breaker has served for up to forty years and it is still functional, make sure you change it so that your family can benefit from renewed protection from electric shock, and fire.

Climate and prevailing environmental conditions have an effect on the lifespan of a circuit breaker. For instance, exposure to chemicals and moisture can lead to a reduction in the lifespan of a circuit breaker due to corrosion and rust. On the other hand, when a circuit breaker is used under moderate and dry weather conditions, it will last longer. This explains why a circuit breaker that is used indoors tends to develop less faults than one used in an outdoor location.

Just as human beings benefit from physical exercise, a circuit breaker also does. To prolong the lifespan of a breaker and to make it more durable, make sure you flip the switch between the on and off position from time to time. By doing this, stiffness and hardness of the switch can be avoided.

What affects the lifespan of a circuit breaker?

So many things have an effect on how well a circuit breaker performs and how long it lasts for. Let’s discuss a few of them.

  1. Environmental factors: Temperature is a major determinant of how long a circuit breaker. When a circuit breaker is placed under harsh atmospheric conditions, its lifespan is shortened. Also, exposure to certain chemicals such as sulphur hexafluoride have a huge impact on how well a circuit breaker performs and how long it will last. It is also important to note that circuit breakers perform better when they are not exposed to fluid or moisture.
  2. Maintenance: They say prevention is better than cure. In similar fashion, it is less stressful to maintain a circuit breaker than to repair a faulty one. From time to time, make sure you inspect the breaker and lookout for defective parts. If any fault is spotted, ensure it is fixed and the part replaced before it becomes a big deal. There is enough evidence to support the fact that devices and electrical appliances last longer when little things are addressed quickly and timely. This principle applies to thermal circuit breakers, standard circuit breakers, hydraulic circuit breakers, magnetic circuit breakers, and all other types of circuit breakers that exist today.
  3. Frequency of use and amount of breaking current: When a device is used often, wear and tear is inevitable. The same can be said of a circuit breaker. The magnitude of current it handles has a huge bearing on its lifespan. Although, its primary role in an electrical circuit is to disrupt the flow of current electricity when there is a short-circuit or an overload, the device may develop a fault or drop in efficiency if this happens too often. This is not unusual especially if you consider the fact that human beings are subject to fatigue when they are overworked or put through their paces. The higher the amount of faulty currents they handle, the more circuit breakers are worked, and the more they are exposed to mechanical failure (since they are electromechanical devices). This applies to all types of circuit breakers.

Conclusion

Circuit breakers must be cared for because of the vital roles they play in securing the lives of human beings and electrical gadgets. Although, they have different operating principles, every type of circuit breaker essentially does the same thing and this explains why there is so much similarity in the way they are maintained. Regardless of the circuit breaker type, poor performance and a short lifespan is inevitable if they are exposed to harsh conditions are badly used/maintained.

As said ab initio, circuit breakers should last for a long time (thirty years to forty years is the estimated range). In fact, some people only have to buy this electromechanical device once in their lifetime as long as it is well utilized.

SEWAGE PUMP – A COMPLETE GUIDE

Definition of a sewage pump

A sewage pump is used for the effective transfer and handling of waste matter. Whether solid or liquid, waste can be efficiently conveyed from one place to another using this device. Sewage pumps are usually submerged and installed at the bottom or base of a sewage basin. Although mostly used in residential buildings and for domestic purposes, sewage pumps can also be used in a commercial setting. An ideal sewage pump should have the ability to handle solid waste up to 1’’ in radius. Some people refer to a sewage pump as a submersible sewage pump because of the way it is installed. So many businesses leverage on the ability of a sewage pump to eliminate waste water in little or no time. This is because sewage pumps are cost-effective and they have the ability to handle a large volume of solid or liquid waste per time.

Sewage pumps are based on the principle of centrifugation. Also, they can either be automatic or manual. There is another classification called the dual-mode and it combines the qualities of an automatic and manual sewage pump. Usually, an automatic sewage pump is the best fit for use in a sewage basin. This is because it is very much capable of handling an overflow.

How does this device work?

Sewage pumps use the principle of centrifugation to transfer sewage from point to point. They are specially designed so that solid waste can pass through them. They are usually powered by electric cords with impressive thickness and reasonable length (usually between 10ft. and 25 ft.). A typical sewage pump has a motor and an impeller. It is the rotational movement of the impeller that supplies the pressure needed to convey fluid from the impeller to the discharge pipe. There are different sewage pump models and each of them has a convenient operating voltage. Some models are rated 575V while others are rated 460V. The size and capacity also has an influence on the voltage rating of a sewage pump. Other smaller models can conveniently run on an 115V or 230V power source. The motor and impeller is shielded with a cast iron covering to make it durable and long-lasting.

Classification of sewage pumps

There are different types of sewage pumps. Let us take a look at a few of them.

  1. Effluent pumps: This type of sewage pump is used to pump liquid waste out of a septic tank. Effluent pumps are very common and popular especially on construction sites. The efficiency of effluent pumps is greater than what solid handling pumps and grinder pumps have to offer because they do not have to deal with solid matter.
  2. A Solid handling pump: Another name for a solid handling pump is sewage ejector pump. This is because it is very efficient for the removal and transfer of solid waste matter. That is not to say solid handling pumps cannot be used to get rid of liquid waste, they can. It is just that they are more suited to handling solid waste as the name rightly suggests.
  3. Grinder pumps: There are lots of similarities between grinder pumps and a solid handling or sewage ejector pump. They are both capable of transferring solid waste from one point to another even when height is involved. The major difference is in the structure and composition. While a grinder pump has parts such as rotating blades, solid handling pumps do not. The rotating blade gives the grinder pump the ability to crush and cut solid waste to smaller fragments before pumping is done. Hence the name ‘grinder pump’. In most cases, there are different grinding methods

What are the benefits of using a sewage pump?

Sewage pumps do not only give you control over solid and liquid waste, they have other benefits. Below are a few of them.

  1. It reduces the risk of flood: We all know that flood has to do with the accumulation of liquid (particularly water). After a heavy downpour, there is a chance that some part of the house will be submerged in flood water particularly when the drainage is not good enough.  This will not only lead to destruction of properties, it is also an environmental hazard. By investing in a sewage pump, this situation can be arrested and promptly brought under control.
  2. It reduces the risk of fire: When a flood occurs, appliances are at risk. It is not a good thing for water to come in contact with electronic appliances. It causes a short-circuit especially in heaters and washing machines and this can lead to electric shock and fire.
  3. Having a sewage pump can help your health because it leads to a cleaner, safer environment. Germs and infections that are capable of causing sickness and diseases will find it difficult to thrive. Futhermore, without sewage pumps, environmentally pollution will be rife and common because there will be no other means to control solid and liquid waste that could be toxic, harmful, and unhealthy.

How do I maintain a sewage pump?

The maintenance of any device is very important if it must serve you for a long time. Nobody wants to buy an item that will need frequent repairs or immediate replacement. So, what can be done to maintain a sewage pump?

  1. Make sure there is enough space for the exchange of air between the interior discharge pipe and the exterior discharge pipe. If there is an obstruction, get rid of it.
  2. Make sure you obey every installation instruction. If you are finding this difficult to do, reach out to an expert. Proper installation is the first stage of maintaining a device.
  3. Get rid of every cover. This permits proper ventilation.
  4. Be sure to put a non-return valve to help with water discharge.
  5. Apply silicone spray from time to time to prevent the exposed metallic parts from corroding.

If you are trying to move a sewage pump from its original position, make sure not to lift it by its wires or cables.

STARTER MOTOR: A COMPLETE GUIDE

What is a starter motor?

The only way to kick an engine into gear is through a starting system. The starting system is essentially a combination of different parts aimed at setting a vehicle in motion. One integral part of a starting system is the starter motor. A starter motor is known by other names. It is also called a self-starter or an electric starter motor. Some people also refer to it as a cranking motor. The importance of a starter motor in an automobile cannot be overflogged. If it develops a fault or it is completely absent, it is literally impossible to move a car. Caring for your starter motor means caring for the life and health of your car. Without a starter motor, no internal combustion engine can be ignited.

The other components of a starting/ignition system are the battery, safety switch, cables, ring gear, and ignition switch. Electric starter motors have become very popular among vehicle manufacturers. Before now, manual starter motors were the most popular. However, due to its inefficiencies and the fact that it posed a huge accident-risk, it had to give way. With an electric starter motor, the need for manual cranking is eliminated.

The major components of an electric starter motor are the pinion drive (which is placed on top of the shaft), starter solenoid, and electric motor.

How does a starter motor work?

Without a starter motor, it becomes difficult to crank up an internal combustion engine. To crank up the engine of a vehicle, a starter motor collaborates with the battery and starter solenoid which is responsible for shutting the circuit when electric current flows through the motor. The starter solenoid is also responsible for the transmission of kinetic energy from starter motor to the flywheel.

When a vehicle is ignited, it is the starter relay that first gets activated through current emanating from the battery. The starter relay is responsible for conveying current with higher magnitude to the starter solenoid. The starter solenoid then plays its part as explained earlier. It is after this that the motor will begin to rotate.

After the flywheel receives enough energy from the starter motor, it spins at a very great speed and triggers the engine to start. All these steps occur within a very short time frame, usually within few seconds.

A brief overview of the parts of a starting system

Battery: The battery is the primary source of electrical energy in a vehicle. It can be recharged. Most cars run on a 12V battery.

Ignition Switch: The ignition switch is like a router. Without it, the electrical energy supplied by the battery cannot be distributed to the necessary parts. The ignition switch must be in the START position before the starting system can be activated. Without putting on the ignition switch, there will be no flow of electric current.

Neutral safety switch: It is only found in an automatic transmission system. Its counterpart in a manual transmission system is the clutch switch. The neutral safety switch ensures there is no flow of current unless the gear is in the neutral or park state.

Starter solenoid: It provides the energy required to set the pinion gear in motion. The solenoid is made up of a combination of wires which it uses to induce a magnetic field. It also houses two coils – the pull-in coil and hold-in coil. The primary role of the hold-in coil is to regulate the movement of the pull-in coil while it applies considerable force to the solenoid plunger.

Types of starters

There are different types of starter motors and the classification is based on how they are driven. While some are electrically powered, others are manually or mechanically powered. We also have starter motors that are powered by air and hydraulics.

  1. Electrical starter systems: They are very easy and convenient to use and they offer a lot of comparative advantages. Almost all cars manufactured in recent years make use of electrical starter motors. With an electric starter motor, there is no need for cranking up an engine manually. All that is required is the supply of electric current from a primary source (usually a battery) and the car engine will be set in motion upon rotation of the flywheel.
  2. Fuel starter systems: In this type of starting system, the force required to activate the engine of the vehicle is derived from the movement of the pistons. Usually, the fuel starting system is used in large engines or engines that have up to fourteen cylinders.
  3. Pneumatic starter systems: The components of a pneumatic starter system are rotating turbines, compressor pump, and pressure tank and it is driven by compressed air. It is the force of compressed air after it is discharged from the steel pressure tank that is used to set the rotating turbine in motion. In turn, the rotating turbine sets the flywheel in motion since they are connected by reduction gears. There is a lot of similarity between this type of starter motor and the electric starter motor. The major thing about pneumatic starter motors is that they are mostly used in diesel engines such as trucks, and ships. The design of a pneumatic starter motor is not complicated and it offers a high degree of reliability.

How do I troubleshoot a starter motor?

It is not uncommon for a starter motor to have problems or develop a fault. Having an idea of what to do and how to troubleshoot would be very useful in such situations. Let’s discuss some key moves that you could make when you need to fix such problems.

  1. Try to find out what the problem is. It is not rocket science. No starter motor will pack-up completely without giving any previous signs.
  2. Remove the starter and disassemble it. Inspect the parts and check if it is something you can handle. If you can’t handle it, reach out to an expert.

QUICK VIEW OF THE DIFFERENT TYPES OF CIRCUIT BREAKERS

What is a circuit breaker?

A circuit breaker is an electrical safety switch that automatically disrupts the flow of electric current when it senses abnormal current or flow of electric charges. It is essentially an electromechanical device that protects other electrical appliances from an overload. It is an important safety device that must be included in an electrical enclosure to help reduce the risk of fire and electrical hazard.

Whenever it senses excess current, the switch opens automatically in what looks like a reflex action. The device can then be reset to its original state by manual means. This is one advantage a circuit breaker has over a fuse. A fuse is functionally useless after a single operation. There are different types and sizes of circuit breakers and this classification is based on the amount of current each device permits to flow through it.

There are three broad categories of circuit breakers– Standard Circuit Breakers, Ground Fault Circuit Interrupters also known as GFCI Circuit Breakers, and Arc Fault Circuit Interrupters otherwise called AFCI Circuit Breakers.

There are subdivisions too. These three categories of circuit breakers are subdivided based on certain features like method of reset, and operating principle. Let’s take a look at all the types and forms of circuit breakers that are in the market today.

  1. Standard Circuit Breakers: Standard circuit breakers have found relevance in homes and commercial buildings. It is not uncommon to see them as single pole or double pole circuit breakers. Double pole circuit breakers are used in situations that require higher voltage or electrical load. A typical example is an electrical circuit where devices like dryers, warmers, electric iron, or heaters are plugged. On the other hand, the single pole circuit breaker is ideal in situations that do not require a high voltage load.
  • Magnetic circuit breakers: Magnetic circuit breakers use a magnetic field induced by an electromagnet to control the flow of electric current. Basically, as the magnitude of the current increases, the strength of the magnetic field decreases and vice versa. Invariably, this means there is a direct relationship between the magnetic field density and the magnitude of electric current that flows through. When the flow of current exceeds the threshold possibly due to an overload or a short circuit, the switch will be triggered and it automatically opens to halt the flow of more electric charges or current.
  • Thermal circuit breakers: As the name suggests, this type of circuit breaker is temperature-dependent. It works based on the principle of temperature difference and it uses a bimetallic strip. It is the same operating principle used by an electric iron that is at work here. In this case, current flows through the bimetallic strip and brings about a rise in temperature. When the bimetallic strip gets heated to its breaking point (the point where it loses its default qualities and properties), the circuit breaker opens automatically and this process will lead to the discontinuation of the flow of electric current. When the temperature of the bimetallic strip becomes reduced, the breakers will also rest to its default state. Hence, there is no need for manual reset. It is important to note that the prevailing environmental condition, i.e. ambient temperature has a huge effect on the effectiveness and performance of a thermal circuit breaker. This is because the temperature of the bimetallic strip is relative to the climate condition of the environment where it is placed.
  • Thermal Magnetic circuit breakers: The operating principle of this type of circuit breaker is a bit unique because it combines the properties of a thermal circuit breaker and a magnetic circuit breaker. If a power surge occurs, the bimetallic strip in a Thermal Magnetic circuit breaker becomes triggered when the overcurrent condition is beginning to last longer than it normally should. Due to the collaborative effort of the thermal and magnetic parts, the Thermal Magnetic circuit breaker offers an extra layer of safety and protection to an electrical enclosure.
  • Hydraulic Magnetic circuit breakers: The Hydraulic Magnetic circuit breaker taps into the power of magnetism and fluid dynamics. Typically, it consists of an electromagnet, an iron core and a fluid which acts as a dampener. The presence of an electromagnet creates a magnetic field which exerts a force on the iron core when an overload occurs. When a short circuit arises, the breaker trips and current flow is discontinued as a result of magnetic flux created by the coil. Whether there is an increase or decrease in temperature, the Hydraulic Magnetic circuit breaker is largely unaffected and this is one comparative advantage it has over other types of circuit breakers.
  • Arc Fault Circuit Interrupters (AFCI): They are also called AFCI circuit breakers and they are very effective at reacting to arcing. Invariably, they help to prevent the unreasonable heating of electrical wires and cables which is capable of triggering fire. Anytime a dangerous arc fault is sensed, the breaker trips and the flow of electric current stopped. Usually, an arc fault happens when current flows through a point it isn’t supposed to pass.
  • GFCI Circuit Breakers: Ground fault circuit interrupters disrupt the flow of electric current when it detects a difference between the magnitude of the outgoing current and incoming current. Usually, the maximum permissible dichotomy is between 4 milliamps and 6 milliamps. When this threshold is exceeded, the Ground Fault Circuit breaker acts to stop further electric current from passing through and this protects the wiring and electrical enclosure from experiencing a damage.
  • Automotive circuit breakers: This type of circuit breaker is further subdivided into three and the subdivision is based on the method of reset. We have the Type I, Type II, and Type III automotive circuit breakers.

Type I: This one reset automatically after recovering from an overload.

Type II: It also resets automatically albeit the whole system has to be turned off.

Type III: The Type III automotive circuit breaker does not reset automatically. The reset has to be done manually if it must be returned to its default state.

OVERVIEW OF DIFFERENT TYPES OF MOTOR CONTROLLERS & DRIVES

A motor controller is any electrical device that can be used to moderate and control the operations of an electric motor. With a motor controller, the operating speed and torque of an electric motor can be regulated and monitored appropriately. The role of the drive is to help ensure that the power input into a motor is commensurate with output generated by the motor. A motor controller provides total control over when an electric motor starts, pauses, or its operation is brought to a halt.

Basically, motor controllers and drives can be grouped into four broad categories and this categorization is based on the response to input power by the device. The four types of motor controllers and drives are: AC, stepper, DC, and servomotor.

  1. AC motor controllers: Another name for this type of motor controller is variable speed drive. AC motor controllers are also described as AC inverters and adjustable frequency drives due to their method of operation. AC motor controllers work by bringing about an adjustment in the frequency of input power to cause a change in speed and torque of the electric motor. Before investing in an AC motor controller, you must look out for its power rating, voltage classification, and inverter type. This type of motor controller forms an integral part of industrial and household appliances such as fans, blowers, pumping machines etc.
  • DC motor controllers: Unlike AC motor controllers that bring about frequency adjustment before it can influence the operations of an electric motor; DC motor controllers influence the input power through a change in the properties of electric current. In this case, alternating current (AC) is changed to direct current (DC) with different frequency range. The most common area of application of DC motor controllers is as a speed and torque regulatory mechanism in pumps, electrically powered vehicles, and machine tools. Some vital things to look out for in a DC motor controller are power rating, voltage classification, type of output signal, motor type, and loop system.
  • Servomotor: The mode of operation of a servomotor controller is very similar to a DC motor controller. The major dichotomy is that a servomotor offers control over the linear and angular displacement of an electric motor with an extra level of precision. This type of motor controller is used majorly in the construction and manufacturing industries for motion control. Servomotor controllers are also used to moderate the operating speed and torque of an electric motor across various directions and positions. Furthermore, they have the ability to amplify the frequency of analogue signal. They can be propelled either by an alternating current (AC) source and a direct current (DC) source. Some people refer to servomotor controllers as servomotor amplifiers and it is used in robotics, machine tools, and for positioning small and tiny objects.
  • Stepper: Stepper motor controllers and stepper drives are also referred to as step amplifiers and stepper drives respectively. They could also be called motor indexers. Just like servomotor controllers and DC motor controllers, step amplifiers are used in micro-positioning, and several industrial equipments. This type of motor controller has also found usefulness in robotics. Stepper motor controllers modify the input power by converting an alternating current source to an amplified current output. Before deciding on a stepper motor controller, you would want to consider the communication interface, type of output signal, electrical requirements, and the loop system. Both stepper motor controllers and servomotor controllers are very effective devices when it comes to positioning of an electric motor. 

Applications and industrial uses of motor controllers and drives

AC motor drives provide an avenue for us to control the speed and pace of an alternating current motor. Also they are used to control the speed of motor in devices like fans, burner, and pumping machines. The speed and pace of an electric motor controlled by an AC motor controller depends on the rate at which current is changed. AC motor drives can also be used to improve the efficiency of certain appliances like pump and fun. This is done by regulating the speed of these devices to be exactly equal to the basic requirement.

Servomotor controllers are mainly used for position control purposes. They are ideal for control of linear and angular position of an electric motor. They also provide an avenue for the control of velocity and acceleration of electric motors. DC motor drives are used commonly in load-lifting machines such as cranes and winches.

What are the things I have to consider before buying an electric motor controller or drive?

There is a need to understand some basic things about motor types before splashing the cash on an electric motor controller.  A decision must be made on whether variable torque or constant torque is what the motor needs. The suitability of an AC drive for a variable torque application (like in a centrifugal fan) or constant torque application (e.g. conveyor) is highly relative.

Furthermore, if a servomotor controller is your preference, you have a decision to make on whether you want the AC (alternating current) type or DC (direct current) type because these are the two types of servomotors available in the engineering market. A DC servomotor can either be the brushed type or the brushless type. The brushed type works by adjusting the input voltage to the motor and thrives on physical contact while the brushless type almost always needs a drive to function optimally. There are also economic decisions to make such as ease of installation. It is a lot easier to install some electric motor controllers than others. Also, the power rating and electrical capacity of the motor must be weighed appropriately before jumping into conclusions. Other important considerations are AC supply voltage, DC supply voltage, peak output current, maximum output voltage, and continuous output power (which is the current carried by a device or an appliance in vacuum while maintaining the desired range of temperature).

COMPLETE GUIDE TO ACTUATORS

What is an actuator?

An actuator is basically that part of a machine that is responsible for both movement and positioning. This electromechanical device can be powered through various means. It runs hydraulically, manually, and electrically. In physics and engineering, there are two basic motion types – linear, and rotary. Consequently, there are two types of actuators – linear actuators and rotary actuators. The major difference is in the direction of motion. In simpler terms, an actuator is a ‘mover’.

Linear actuators are concerned with straight line movement or linear displacement. These energy conversions are done by the activation of the push or pull function albeit some linear actuators make use of a handwheel. On the other hand, a rotary actuator converts useful energy to rotary or rotational motion. One very common area of application of rotary actuators is in the valve control system. For flexibility and performance purposes, actuators are produced in various shapes and sizes.

What are the various types of actuators?

  1. Electric linear actuators: This electrically powered actuator converts electrical energy to linear motion or displacement. They are used predominantly for automation purposes especially when it is desired that an equipment moves to a particular linear direction. Some common household and industrial devices that make use of electric linear actuators are locking doors and dampers. Belts and lead screws are some common methods used to drive this actuator
  • Electric rotary actuators: As the name suggests, electric rotary actuators are capable of converting electrical energy to rotary or rotational motion. Like electric linear actuators, they are also used for automation purposes. The only difference is that movement isn’t in a linear direction. Electric rotary actuators are used in windows and applied in robotics.
  • Fluid power linear actuators: These types of actuators are mechanically powered. They have a piston-cylinder arrangement like other mechanical engines and they produce straight line movement courtesy of gas and fluid pressure. Fluid power linear actuators are used in welding, clamping, and all other areas where movement to a particular linear direction is desired.
  • Fluid power rotary actuators: There is a lot of similarity between fluid power linear actuators and fluid power rotary actuators. The only difference is in the direction of controlled motion. In fluid power rotary actuators, mechanical energy is converted to linear or straight line displacement whereas in fluid power rotary actuators, energy from a gas or fluid is transformed to rotational or rotary movement. It is the movement of the piston inside the cylinder that supplies the mechanical energy required for the operation. The up and down movement of the piston inside the cylinder is brought about by pressure from a gas or hydraulic fluid just as it is in a conventional internal combustion engine. Fluid power rotary actuators are used in clamping, and in equipments such as dampers and doors.
  • Linear chain actuators: They convert mechanical energy from a collection of chains to useful linear displacement. Linear chain actuators vary in sizes and design and they are used to trigger push and pull motion. Usually, they have a gearing system and this is where the force required to trigger a displacement emanates from.
  • Manual linear actuators: This one produces linear motion by converting mechanical energy gotten from the manual rotation of gears. Typically, a manual linear actuator comprises of gearboxes and knobs or a handwheel. This type of actuator is used for precision purposes in a commercial setting. They are manually driven by the hand.
  • Manual rotary actuators: They are very similar to manual linear actuators. The only difference is that they produce rotational or rotary motion. They are manually operated and the source of power is the rotation of a handheld knob or wheel. They have the same components (knobs, levers, gearboxes, handwheels, and shaft) as manual linear actuators. The most common area of application of manual rotary actuators is in the operation and manipulation of all types of valves (ball valves, globe valves, butterfly valves, etc.).

How and where do we use actuators?

Both linear and rotary actuators are useful for a wide range of domestic and industrial purposes. We already established the fact that they are used as part of a control system. Perhaps the most common area of application of actuators is in the control of valves. They are used for the remote manipulation of valves. We used the word ‘manipulation’ because valve control means a deliberate attempt to turn the valve across several linear and rotational directions at a frequency that is high and logical. Since there are different types of valves, the choice of actuator largely depends on the peculiar properties of the valve.

Actuators are also used for different production and factory purposes such as in a packaging machine. They are also used for clinical and health purposes in medical equipments. Many of the big engines used for transport purposes have actuators in them. A very common example is an aircraft and a train. Furthermore, actuators are used for mechanical processes such as welding, and clamping. They are also commonly used in doors, windows, and dampers. In robotics, actuators, particularly electric rotary actuators are used to provide rotational motion.

What should I consider before choosing an actuator?

Before opting for a particular type of actuator, you must first understand the underlying mechanism and working principles of all actuator types. Also, the method of use and area of application should form a major part of your consideration. For instance, if you are craving for a large amount of force, a hydraulic actuator may be appropriate. Furthermore, if you want a high level of control and you have economic concerns, an electric actuator may be the best option. Another comparative advantage of an electric actuator is that it is quite easy to install and put together.

All in all, your decision should be based on critical factors like stroke length, precision, speed requirement, mode of operation, accuracy of values, efficiency of the actuator, cost implication, control mechanism, etc.

SENSORS, DETECTORS, AND TRANSDUCERS – AN OVERVIEW

Sensors, detectors, and transducers are all electrical devices that help you confirm the presence of an external object or substance. These devices help you respond to certain phenomenon in a prompt and responsive manner. There are different types of sensor, detectors, and transducers in the market today and most of them help you verify the physical presence of metals, flame, gas, and even human beings. For instance, a fire alarm gets triggered whenever there is an inferno or flame because of the presence of a sensor.

Some sensors help you gauge certain physical properties such as the temperature of an external body or the pressure of flow inside a pipe. Sensors, detectors, and transducers are able to do what they do because of the presence of some highly sensitive materials. The way and manner each of these devices operates are quite different and it is highly dependent on the area of application or where they are being applied. Across different industries, these devices are very useful because they provide a means for controlling and measuring various industrial processes.

Some common types of sensors, detectors, and transducers

  1. Metal sensors: Most metal sensors work based on the principle of electromagnetism. As the name suggests, they are used to confirm the presence or absence of metallic substances or bodies. Metal sensors have found importance in a wide range of devices. For instance, the security devices used in airports and banks contain metal sensors. There are two types of metal detectors – the permanent and portable types. Metal detectors are very useful for different manufacturing processes.
  • Leak sensors: Leak sensors/detectors help you verify the leakage of fluid. With a leak sensor/detector, it becomes easier to know if there is an undesired discharge of a certain type of liquid or gas. Leak sensors/detectors have different underlying principles. While some work based on the principle of ultrasonic sound, others work with foaming agents. Basically, leak sensors/detectors are more commonly used by gas engineers and in the petroleum industry. They are also useful in plumbing and piping.
  • Force sensors: Force sensors are used to detect different types of forces – weight, torque, push, load, pull etc. After a force is detected, signal is sent to the output or control device. Force sensors/detectors do not work in isolation. They collaborate with load cells to confirm if substantial force is present in a particular situation or not. The resistance of these load cells are altered when their load-bearing capacity is exceeded. Just so you know, load cells are piezoelectric devices. Force sensors are used whenever there is need to measure the size of a load.
  • Flame sensors: These are flame/fire-detecting devices. Whenever flame detectors detect fire, they send a quick signal to the controlling device. This is the logic behind the operation of fire alarms. They are also used in burners, safety devices and other combustion devices. Flame sensors/detectors get triggered whenever ultraviolet or infrared wave of flame is spotted.
  • Gas and chemical sensors: These types of sensors/detectors are used to detect the presence of certain types of gases and chemicals. They are used for a wide range of purposes such as detection of gas or chemical leakage, monitoring of spaces, and for instrumentation purposes in the laboratory. They are designed to be able to detect the presence of not just one type of gas or chemical.
  • Flow sensors: With flow sensors, it becomes easier to detect the flow of solids and fluids (liquids and gases). Typically, flow sensors are electromechanical devices which mean they make use of a combination of electrical and mechanical energy to carry out their operation. Also, a flow sensor makes it possible to measure certain flow properties such as flow rate (the amount of a given fluid that passes through a point at a given instance of time), flow pressure, and operating temperature. Flow sensors are used for many industrial purposes.
  • Flaw sensors: They help you identify flaws without having to break a sweat. With a flow sensor, spotting defects and inconsistencies in materials and structures becomes easier. They make use of acoustic and ultrasonic means to detect faults before sending a signal to an output device.
  • Humidity sensors: These sensors make it possible to know how much water is in the air or atmosphere before the outcome is sent to a display device.
  • Motion sensors: Motion sensors/detectors are devices that have the ability to sense the movement of bodies and particles. They also make it possible to understand the speed and direction in which an external body is moving.
  1. Electrical sensors: Electrical sensors/detectors have the ability to detect electric current and voltage. Their response is based on their findings and this is sent to a visual display where the value can be read. Electrical sensors can be found in so many devices such as electric fan, electric pump, etc.
  1. Temperature sensors: Temperature sensors have the ability to detect every degree increase or decrease in the temperature of a body before sending the correct value as a signal to a display device. Temperature sensors give you an idea of properties like thermal conductivity, thermal resistivity, ambient temperature, as well as the maximum and minimum temperature of a body or particle. Whether it is a solid, liquid, or gas, temperature sensors will give you an idea of their thermal characteristics.
  1. Radiation sensors: Radiation sensors and detectors are devices that can sense radiant energy whether it is alpha ray, or beta and gamma particles. Radiation sensors are used for clinical and survey purposes.

Where can I buy a sensor or transducer?

There are so many companies that deal in the manufacture and supply of transducers, detectors, and sensors. Below is a list of the top companies that render these services.

  • Wasco switches and sensors.
  • VPG transducers
  • Innovative sensor technology
  • Unmanned systems source
  • Locon sensor systems, Inc.
  • Keller America, Inc.
  • IFM Efector, Inc.
  • Allen-Bradley/Rockwell automation.
  • Madison Company.

CHARACTERISTICS OF A LIMIT SWITCH

What is a limit switch?

A limit switch is essentially a device used by electrical engineers as part of a control system. It allows you determine if an object is present in a machine and also forms the basis for studying the movement of such items. Originally, limit switches were intended to allow you define the range at which objects could travel before their movement is brought to a halt. Furthermore, it gives you an idea of the number of objects that have passed through a particular point. With a limit switch, you have total control over a piece of equipment.

How does it work?

The fact that a limit switch is an electromechanical device means it makes use of both electrical and mechanical energy. It consists of an actuator that is strategically connected to contacts. When the actuator senses that an object is in close contact with it, the contacts get triggered and an electrical connection is either initiated or discontinued. An electrical connection is initiated or broken based on the state of electrical switch and it is the actuator plunger that is responded for this change of state. There are a few other devices that are closely related to a limit switch. Photoelectric sensors and inductive proximity sensors are devices that are very much capable of performing the same function. The major difference in the modus operandi of a limit switch and these other devices is that they do not necessarily have to be in close contact with an object. Also, limit switches are more efficient than these proximity sensors because they are very much capable of handling higher electrical current.

What are the parts of a limit switch?

As stated ab initio, a limit switch is made up of an actuator and a set of contacts. It also has electrical terminals, an operating head, and a switch body which houses the switch contact mechanism. There is an impressive synergy between the actuator and operating head. It is the motion of this operating head across different directions that the actuator reads to start or end the operation of the switch. The terminals of a limit switch are linked to the contacts and this provides a platform for the joining of electric cables to the device.

Limit switches are a core part of industrial machinery. This is because these equipments will not function effectively without a control mechanism and it is a limit switch that helps keep their performance in check. However, to get the best out of a limit switch, it must be properly installed and adequately maintained. Other factors that have an effect on the efficiency rating of a limit switch are stroke rate, size, and force.

How is a limit switch used?

Typically, a limit switch does not step into action unless a moving object (usually a machine or component of a machine) is brought in close physical contact with the actuator. The limit switch coordinates the activities of the electrical circuit which is the major controller of a machine. Also, limit switches have the uncanny ability to direct the activities of an electric motor by setting the tone for its functionality. Basically, with a limit switch, you have control over when an electric motor starts, accelerates, decelerates or stops. A limit switch can be included in machinery as part of an effective control system.

What are micro limit switches and sub miniature micro switches?

They are also called micro switches and as the name implies, they are smaller in size when compared to the usual limit switches. Their compact size makes it possible for them to be installed in tighter and narrow spaces and this is a comparative advantage. This type of limit switches can be found mostly in electrical control circuits.

There are a few similarities between the conventional limit switches and micro switches and one of such is that they both have actuators and a set of contacts. The electrical rating of these contacts is usually within the range of 10 amperes and 15 amperes.

On the other hand, sub miniature micro switches can be used in spaces that are narrower. They are smaller in size and more compact in design. A typical sub miniature micro switch is half the size of a micro limit switch and it is suitable for use in machinery with limited space. The structure of contacts in a sub miniature micro switch is quite similar to what is obtainable in a micro limit switch. The electrical rating of contacts in a sub miniature micro switch is within the range of 1 ampere and 7 amperes.

Pros and cons of a limit switch

The use of a limit switch comes with a few limitations and several advantages. Here a few.

  1. Limit switches are not hard to install or set up.
  2.  The design of limit switches is not complicated.
  3. These devices are usually sturdy and strong.
  4. They are very much capable of handling high current and voltage.
  5. They do not consume much electrical power.
  6. Their readings are usually very accurate and when readings are taken repeatedly, the values obtained are close.
  7. Limit switches are sturdy and strong.
  8. They are not streamlined to a particular industrial setting and this says a lot about the flexibility of limit switches.
  9. Limit switches are very easy to operate.

Let’s look at the flip side.

  1. They are not particularly suitable for equipments that operate at a high speed.
  2. Without close physical contact, it is not possible to get limit switches to work. This is unlike proximity switches that do not need physical contact with the target (the object) before they are put to use.

Due to how they are designed, limit switches tend to lose a bit of accuracy when they are used over a long period of time. This means they are subject to wear and tear. Hence, there is a need to replace them from time to time.