Initial Transfer To The "Standby" Source - Guardian 5240 Diagnostic Repair Manual

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Table of Contents

SECTION 4.2

OPERATIONAL ANALYSIS

The generator is running, the circuit board's "engine warm-up timer" is timing, and generator AC output is avail-

able to transfer switch terminal lugs E1 and E2 and to the open contacts on the transfer relay. Initial transfer to the

STANDBY power supply may be briefly described as follows:

• 12 volts DC output is delivered to the transfer relay (TR) actuating coil, via Wire 194, and terminal A of the

transfer relay (TR) in the transfer switch. This 12 volts DC circuit is completed back to the board, via transfer

relay terminal B, and Wire 23. However, circuit board action holds the Wire 23 circuit open to ground and the

transfer relay (TR) is de-energized.

• When the circuit board's "engine warm-up timer" times out, circuit board action completes the Wire 23 circuit to

ground. The transfer relay then energizes and its normally open contacts close.

BATTERY

CHARGER

SCR

ELECTRONIC

VOLTAGE

REGULATOR

MANUAL

194

CONTROL

PRINTED CIRCUIT

BOARD

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