The utility power supply
The ordinary power is offered by the utility power company and then connected to onsite applications. In situations where the primary power source has stopped to work, the power from a new or used generator can either be automatic or manually transferred to the onsite application using a transfer switch.
The main purpose of the transfer switch is to resupply power from the grid to a backup source of power. In this article, we are going to explain the mechanism used by the control panel to direct an automatic transfer switch.
The control panel system of a transfer switch is what enables the system to be automatic in nature. The manual transfer switches are operated using onsite personnel as well as being used in situations where the load is normally not of emergence nature as requiring quick restoration of the power supply. Using an automatic transfer switch, the power failures are identified as soon as they want to occur and the transition from the utility power to the generator power has no limitations.
The control panel task is to detect the power failure and take trigger the procedures to start the new or used generator. Once the generator has reached its exact voltage and the frequency the control unit alerts the switch to shift from the normal source of power to the generator.
The fundamental basics of the engineering behind the transfer switch are quite complicated as different components are involved in making sure it works as it is intended.
The frequency as well as the voltage
One of the major functions of the control panel involves the detection of the drop in voltage as well as a completed failure within the normal power source. Normally, all phases are being monitored. Any failure at any point is defined as a drop in voltage below the current setting upon any phase. The voltage, as well as the frequency information, is obtained and offered by the sensors to the control panel so as to determine the load existence. The minimal frequency and voltage should be attained before the transfer of the load to the new or used generator take place. This is important in making sure that the generator set is capable of accepting the load.
The time delays
The automatic transfer switches are offered in different types of time delay units. The time delay operation is a necessary feature when it comes to an automatic switch due to false alarms triggers that are caused by the normal power source from the utility company.
The common prevalent rime delay that overrides any momentary traditional outages that might cause a false engine to start and hence transfer the load. This time delay ranges from 0-6 seconds, with a single second being the common configuration.
The delay has to be short enough to bride the backup power source while complying to the city, state as well as the federal codes.
As soon as the normal power is restored, another time delay is required so as to make sure that the load is stable enough to change from the backup power. Traditionally the delay is between 0-30 minutes. The control panel should be able to automatically pass this time delay when it is returning to the normal source in a situation where new or used generator fails while the normal power source is working as required once again.
The third most common time delay includes a cool downtime for the engine. During this period the controls operate the engine unloaded before they shut it off.
Under most circumstances, it is normally desirable for the load to be moved to the backup generator as soon as the sufficient voltage and frequency have been achieved. But in some of the situations, the end-users need to sequence the different transfer switches upon the backup generator.
In case this application needs, the controls to include extra time delay that can be adjusted upon each transfer switch so that the load can be able to transfer the new or used generator in whatever desired order.
The engine control contact pint
This includes a contact point that alerts the engine control to start when normal power is supplied from the grid. In most common modern designs, this contact is normally a dry contact that closes whenever there is a failure of this normal power.
As the contact closes it, completes the circuit from the cranking batteries connecting it to the engine start control systems. In other words, these contact points open so as to shut down the new or used generator
There should be regular testing that is done upon the contact point so as to make sure that there is no failure of the circuit. When it comes to certain transfer switches there are backup contact points in copy circuits that ensure there is not any single point of failure.
The control unit testing
There should be scheduled regular testing as part of maintaining an emergency backup power system. All control units should consist of a manually operated switch so as to stimulate the normal power source when it fails. The controls that are described in this post are normally considered as the traditional/ standard when it comes to operating a transfer switch.
The guidelines that were elaborated have to be used as the minimum standard that the end-user should always depend on before making the decision to buy a transfer switch. There are quite different types of specific control units that are used in handling different applications. It is better to contact your electrical contractor so as to discuss which type of control system that will work to full fill your needs.