Generac Power Systems 941-2, 940-2 Dirt and Moisture, Insulation Resistance Testers, Stator Leads

Section 1.4

INSULATION RESISTANCE

DIRT AND MOISTURE

If moisture is permitted to remain in contact with the generator Stator windings, some of it will be retained in voids and cracks of the winding insulation. This can eventually cause a reduction in insulation resistance and generator output may be affected.

Winding insulation in Generac generators is moisture resistant. However, prolonged exposure to water, high humidity, salt air, etc., will gradually reduce the resistance of winding insulation.

Dirt can make the problem even worse, since it tends to hold moisture into contact with the windings. Salt, as from sea air, can also worsen the problem, since salt tends to absorb moisture from the air. When salt and moisture combine, they make a good electrical conductor.

Because of the detrimental effects of water, dirt and salt, the generator should be kept as dry and as clean as possible. Stator windings should be tested periodi- cally using a Hi-Pot tester or a Megohmmeter. If insu- lation resistance is low, drying of the unit may be nec- essary. If resistance is still low after drying, the defec- tive Stator should be replaced.

INSULATION RESISTANCE TESTERS

One kind of insulation resistance tester is shown in Figure 1, below. Other types are commercially avail- able. The type shown has a "Breakdown" lamp which turns on to indicate an insulation breakdown during the test.

One common type of tester is the "Megohmmeter" which measures resistance in "Megohms".

CAUTION! When using a Megohmmeter or

!any other tester, be sure to follow the manu- facturer's instructions carefully. All Stator leads must be isolated from other compo- nents, especially circuit boards, before per- forming tests. The high voltages used in test- ing insulation resistance will damage elec- tronic components.

STATOR LEADS

The following leads are brought out of the Stator and connected to various components in the unit:

WIRE#	COLOR	CONNECTS TO
AC1	Grey	CB1A
AC2	Yellow	BR1
SL1	Orange	CB1B
SL2	Brown	BR3
TIM1	Orange	A6060 Circuit Board
TIM2	Grey	A6060 Circuit Board
PS1	Red	J1
PS2	Black	J1
77	Brown	Battery Charge Rectifier BCR
66	Brown	Battery Charge Rectifier BCR
55	Black	Grounding Terminal

Figure 2. Stator Leads

	PREPARATION FOR TESTS
	See Stator leads CHART above. Disconnect and iso-
	late all Stator leads. ALL STATOR LEADS MUST BE
	DISCONNECTED AND ISOLATED BEFORE START-
Figure 1. One Kind of Hi-Pot Tester	ING THE TESTS.

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