Emergency Power Supply System (EPSS) Load Bank Testing Using TripleSwitch™
Electrical Disconnect Simplifies Testing of Emergency Generators

Diagrams below represent TripleSwitch™ operating functions during various conditions.

	● The permanent generator is hard wired into ESL’s TripleSwitch. The output from the TripleSwitch is hard wired to the facility ATS. ● Under normal conditions the center breaker is “ON,” connecting the permanent generator to the facility ATS.
	● If the ATS needs emergency power, a start-up signal is sent from the ATS to the permanent generator. Once the ATS detects proper voltage, frequency and phase sequence, the ATS switches over.
	● When load bank testing of the permanent generator is required, a portable (or permanent) load bank tester is connected to the load bank connection point in the TripleSwitch. The center breaker is left “ON.” Next, the left hand breaker is turned “ON.” This connects the permanent generator to the load bank connection. The permanent generator can be started, and load bank testing can be done. In the event of a utility power loss to the facility, the ATS is prewired to a shunt trip in the left hand breaker tripping the breaker and allowing the permanent generator power to feed the facility.
	● When load bank testing is in progress both the left side load bank breaker and center ATS breaker are on (closed). If the utility power is lost during the load bank test, a signal from the ATS is sent to the shunt trip on the left side load bank breaker to open the breaker. The center breaker is on (closed) and the power from the generator is immediately redirected through the center ATS breaker to the facility.
	● Anytime the permanent generator is disconnected from the emergency system (maintenance, repairs, etc.) the annunciator circuit is activated. A separate portable (or secondary permanent) generator can be connected to the portable generator connection point, and by turning “ON” the right hand breaker the portable generator is connected to the emergency system.