Product Manual A

3. Description11-2017

3.3.1.3 Sync Check Sensor

Sync Check is used to determine when both sources of power are within specified tolerances of

frequency, voltage, and relative phase difference. If both sources are within this range, a fast or

synchronized transfer occurs.

Default Value:

• Frequency bandwidth: 1.0 Hz

• Voltage: 10 V

• Offset: 0 milliseconds

Range:

• The frequency bandwidth range is from 0.1 and 1.0 Hz.

◦ The frequency difference between the sources must be equal to or less than the set value in

order for transfer to occur.

• The voltage window is from 5 and 25 volts.

◦ The average voltage difference between the two sources must be equal to or less than the set

value in order for transfer to occur.

Sequence of Events: If enabled, the Sync Check sensor overrides programmed transition whenever

transferring between two live sources. If only one power source is available, programmed transition

overrides the Sync Check sensor.

3.3.2 Programmed Transition

Programmed transition executes a programmed transition (PT) transfer by disconnecting the load from the

source of power, pausing in the neutral position of the transfer switch (between switched positions) to

allow transient voltages from the load to diminish, and then the load is switched to the other source.

3.3.2.1 Transfer from Source 1 to Source 2 (PT)

This sequence includes a programmed transition and begins with Source 1 supplying power to the load.

The Source 1 Available and Source 1 Connected indicators are lit. The sequence ends with Source 2

(generator) assuming the load.

1. When source 1 goes “out of spec," the control starts a Time Delay Engine Start (TDES) timer and

the Source 1 Available indicator goes out.

2. If the TDES expires without a return to acceptable Source 1 power, the genset receives a remote

start signal. The engine starts and accelerates to rated speed.

3. When the alternator output reaches the “pickup" level, the Source 2 Available indicator lights. The

transfer switch starts the Time Delay Normal to Emergency (TDNE) timer. When this time is

complete, the switch moves to the Neutral position. The Source 1 Connected indicator goes out.

4. The transfer switch stops in the Neutral position for the Time Delay Programmed Transition (TDPT)

and then completes its transition to the Source 2 position. The Source 2 Connected indicator lights.

3.3.2.2 Transfer from Source 2 to Source 1 (PT)

This sequence begins with Source 2 supplying power to the load. The Source 2 Available and Source 2

Connected indicators are lit. The sequence ends with Source 1 (utility) assuming the load.

1. When Source 1 returns to “in spec," the Source 1 Available indicator lights and the digital board

starts the Time Delay Emergency to Normal (TDEN) timer. When this time is complete, the switch

moves to the neutral position (the Source 2 indicator goes out).