Generac Power Systems 16 kW NG, 10 kW LP, 13 kW NG Test 27 Check Manual Transfer Switch Operation

Transfer switch

Part 3

Section 3.4

Diagnostic tests

e.Set the generator AUTO-OFF-MANUAL switch to AUTO.

(1)The generator should crank and start.

(2)When the generator starts, an “engine warm-up timer” should start timing. After about 15 seconds, the transfer relay should energize and transfer to the “Standby” source should occur.

f.If transfer to “Standby” does NOT occur, check the voltage across transfer switch Terminal Lugs E1 and E2. The generator line-to-line voltage should be indicated.

RESULTS:

1.If normal transfer to “Standby” occurs, discontinue tests.

2.If transfer to “Standby” does NOT occur and no voltage is indicated across Terminal Lugs E1/E2, determine why generator AC output has failed.

3.If transfer to “Standby” does NOT occur and voltage reading across Terminal Lugs E1/E2 is good, refer to Flow Chart.

Test 27 – Check Manual Transfer

Switch Operation

DISCUSSION:

In automatic operating mode, when utility source volt- age drops below a preset level, the engine should crank and start. On engine startup, an “engine warm-up timer” on the generator circuit board should start timing. When that timer has timed out (about 15 seconds), the transfer relay should energize to deliver utility source power to the standby closing coil terminals. If normal

utility source voltage is available to the standby closing coil terminals, but transfer to Standby does not occur, the cause of the failure may be (a) a failed standby closing coil and/or bridge rectifier, or (b) a seized or sticking actuating coil or load contact. This test will help you evaluate whether any sticking or binding is present in the transfer mechanism.

PROCEDURE:

1.With the generator shut down, set the generator AUTO-OFF-MANUAL switch to OFF.

2.Set the generator main circuit breaker to OFF or “Open”.

3.Turn off the utility power supply to the transfer switch, using whatever means provided (such as a utility source main line breaker).

*DANGER: DO NOT ATTEMPT MANUAL TRANSFER SWITCH OPERATION UNTIL ALL POWER VOLTAGE SUPPLIES TO THE SWITCH HAVE BEEN POSITIVELY TURNED OFF. FAILURE TO TURN OFF ALL POWER VOLTAGE SUPPLIES MAY RESULT IN EXTREMELY HAZARDOUS AND POSSIBLY LETHAL ELECTRICAL SHOCK.

4.In the transfer switch enclosure, locate the manual transfer handle. Handle is retained in the enclosure with a wing nut. Remove the wing nut and handle.

5.See Figure 2. Insert the un-insulated end of the handle over the transfer switch operating lever.

a.Move the transfer switch operating lever up to actuate the load contacts to the Utility position, i.e., load connected to the utility source.

LOAD CONNECTED TO

UTILITY POWER SOURCE

MANUAL

TRANSFER

HANDLE

TRANSFER

SWITCH

OPERATING

LEVER

LOAD CONNECTED TO

STANDBY POWER SOURCE

TRANSFER

SWITCH

OPERATING

LEVER

MANUAL

TRANSFER

HANDLE

Figure 2. Manual Transfer Switch Operation

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