Guardian Technologies 4760, 4456, 4390 Test 22 Check Voltage AT Standby Closing Coil C2, Results

SECTION 3.4

DIAGNOSTIC TESTS

PART 3

V-TYPE PREPACKAGED TRANSFER SWITCHES

d. Actuate the generator main line circuit breaker to its "On" or "Closed" position. The utility power supply to the transfer switch must be turned OFF.

e. Set the generator AUTO-OFF-MANUALswitch 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, go on to Test 22.

TEST 22 - CHECK VOLTAGE AT STANDBY

CLOSING COIL C2

DISCUSSION:

Standby source voltage is used to energize the standby closing coil and actuate the main contacts to their "Standby" source side. Standby source alternating current (AC) is changed to direct current (DC) by a bridge rectifier before reaching the closing coil. This test will determine if standby voltage is available to the closing coil.

If normal standby source voltage is available to the terminals of the standby closing coil but transfer to "Standby" does NOT occur, look for (a) binding or sticking in the transfer mechanism, (b) a defective coil, or (c) a bad bridge rectifier. The coil and the bridge rectifier must be replaced as a unit.

PROCEDURE:

1.Set the generator main line circuit breaker to the OFF or “Open” position.

2.Set the generators AUTO-OFF-MANUAL switch to the OFF position.

3.Set your VOM to measure AC voltage.

DANGER: BE CAREFUL! HIGH AND DANGEROUS VOLTAGES ARE PRESENT AT TERMINAL LUGS WHEN THE GENERATOR IS RUNNING. AVOID CONTACT WITH HIGH VOLTAGE TERMINALS OR DANGEROUS AND POSSIBLY LETHAL ELECTRICAL SHOCK MAY RESULT. DO NOT PERFORM THIS VOLTAGE TEST WHILE STANDING ON WET OR DAMP GROUND, WHILE BAREFOOT, OR WHILE HANDS OR FEET ARE WET.

4.Disconnect Wire E2 from the standby closing coil (C2). Connect one meter test Lead to Wire E2. Use a suitable and safe connection to this wire, such as an alligator clip that attaches to the meter test probe. Isolate this wire and test probe from any other potential source or ground.

5.If necessary, repeat Step 2 under "Procedure" of Test 21. The system must be in automatic operating mode, with engine running, and standby source voltage available to terminal lugs E1 and E2.

6.Locate on the standby closing coil the terminal that Wire B is connected to. (Figure 1, previous page). Connect the other meter test lead to this terminal. Generator line to line voltage should be indicated. If generator voltage is NOT indicated, proceed to Step 7.

7.With Wire E2 still connected to one test probe, connect the other meter test lead to Wire 205 on Limit Switch XB1(see Figure 1 on previous page). Generator line to line voltage should be measured.

RESULTS:

1.If generator line-to-line voltage is indicated in “Procedure, Step 6,” but transfer does NOT occur, proceed to Test 24.

2.If generator line-to-line voltage is NOT indicated in “Procedure, Step 7,” proceed to Test 33.

3.If generator line-to-line voltage is indicated in “Procedure, Step 7,” proceed to Test 25.

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