Product Manual A

4. Operation11-2017

7. When the generator output is acceptable (the Generator set Power Available LED is lit) the control

starts the TDNE timer.

8. After the TDNE timer expires, the transfer switch transfers to the generator set (the Generator set

Power Connected LED is lit).

9. The control continues to run the generator with the transfer switch connected to the generator set

until the control panel Test pushbutton is momentarily pressed or the ground is removed from the

Remote Test input.

10. After this action, the control starts the TDEN timer. The Test LED flashes twice per second for two

seconds to acknowledge the operation and then the Test LED goes out.

11. After TDEN timer expires, the transfer switch retransfers back to the utility (the Utility Power

Connected LED is lit).

12. Once the transfer switch is connected to utility power, the control starts the TDEC timer.

13. After the timer expires, the control energizes the start relay, opening the start contact to signal the

generator to stop.

4.3.3 Test Without Load - Sequence of Events

The following describes the sequence of events of a transfer switch during a test without load.

In this example, the generator is started and runs without load for the duration of the test.

The utility must be acceptable during the entire test event. Acceptability is determined by the active source

sensor (under-voltage sensor). If, at any time, the under-voltage sensor determines that the utility is not

acceptable, the test is terminated.

Before a test can begin, the transfer switch must be connected to the utility power source and utility power

must be available.

1. Verify that the transfer switch is set to test without load.

2. Verify that the green Utility Power Connected LED on the control panel is lit.

3. Verify that the green Utility Power Available LED on the control panel is lit.

4. Press and hold the control panel Test pushbutton for two seconds or ground the Remote Test input

to initiate the test. The Test LED flashes two times per second for two seconds, acknowledging that

the test was activated. Once the test period starts, the Test LED stays on continuously.

5. The control de-energizes the start relay, closing the start contact to signal the generator to start.

When the generator set starts and produces power, the amber Generator set Power Available LED

lights.

6. The control continues to run the generator without load until the control panel Test pushbutton is

momentarily pressed or the ground is removed from the Remote Test input.

7. After the control panel Test pushbutton is momentarily pressed or the ground is removed from the

Remote Test input, the control flashes the Test LED twice per second for two seconds to

acknowledge the operation and then goes out.

8. The control energizes the start relay, opening the start contact to signal the generator to stop.

4.4 Sensors

4.4.1 Utility Sensor

The utility sensor monitors all phases of the utility for under-voltage conditions. Both the pickup and

dropout set points are adjustable. The set points are listed in the following table.