SECTION 3.2

OPERATIONAL ANALYSIS

PART 3

V-TYPE PREPACKAGED TRANSFER SWITCHES

UTILITY SOURCE VOLTAGE FAILURE

If utility source voltage should drop below a preset value, the generator circuit board will sense the dropout. That circuit board will then initiate generator cranking and startup after a time delay circuit times out.

Figure 3 is a schematic representation of the transfer switch with generator power available, waiting to transfer.

Generator voltage available E1, E2.

Circuit board action holding Wire 23 open to ground.

Power available to standby coil C2, upon closure of TR, normally open contacts (9 & 6) will close and initiate a transfer.

Figure 3. Generator Power Available, Waiting to Transfer.

Page 3.2-3

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Guardian Technologies 4758, 4456, 4390, 4389 Utility Source Voltage Failure, Generator Power Available, Waiting to Transfer