Guardian Technologies 4389 TEST 21- CHECK VOLTAGE AT TERMINAL LUGS E1, E2, Section, Part, General

V-TYPE PREPACKAGED TRANSFER SWITCHES

PART 3

SECTION 3.4

DIAGNOSTIC TESTS

GENERAL

Test numbers in this section correspond to the numbered tests in Section 3.3, "Troubleshooting Flow Charts". When troubleshooting, first identify the problem. Then, perform the diagnostic tests in the sequence given in the flow charts.

TEST 21- CHECK VOLTAGE AT TERMINAL

LUGS E1, E2

DISCUSSION:

In automatic mode, the standby closing coil (C2) must be energized by standby generator output if transfer to the "Standby" source is to occur. Transfer to "Standby" cannot occur unless that power supply is available to the transfer switch.

DANGER: BE CAREFUL! HIGH AND DANGEROUS VOLTAGES ARE PRESENT AT TERMINAL LUGS E1 AND E2 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.

PROCEDURE:

1.If the generator engine has started automatically (due to a utility power source outage) and is running, check the position of the generator main circuit breaker. The circuit breaker must be set to its "On" or "Closed" position. When you are sure the generator main circuit breaker is set to "On" or 'Closed", check the voltage at transfer mechanism terminal lugs E1 and E2 with an accurate AC voltmeter or with an accurate volt-ohm- milliammeter (VOM). The generator line-to line voltage should be indicated.

2.If the generator has been shut down, proceed as follows:

a.On the generator control panel, set the AUTO- OFF-MANUALswitch to OFF.

b.Turn OFF all power voltage supplies to the transfer switch. Both the utility and standby power supplies must be positively turned off before proceeding.

c.Check the position of the transfer mechanism main contacts. The moveable LOAD contacts must be connected to the stationary UTILITY source contacts. If necessary, manually actuate the main contacts to the "Utility" power source side.

Figure 1. The “V-Type” Transfer Mechanism

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