FIELD RELAY

ELECTRICAL

NOTE: If turning the variable resistor

does not cause the regulator to

operate on the lower set of contacts,

return the variable resistor to the "no

resistance" position, turn the carbon

pile to slightly load the battery, and

then adjust the variable resistor to

cause the regulator to operate on the

lower set of contacts.

NOTE: The most desirable method of

determining that the regulator is

operating on the lower set of

contacts is to use earphones

connected from the regulator "F"

terminal to ground. As the variable

resistor is turned, and operation

changes from the upper set of

contacts to the lower set, the

earphone sound will fade away and

Figure 25.

stop completely and then return

when the lower set of contacts

begins to operate.

The alternate

method is to observe the voltmeter

change from one value to another,

but this is less desirable since it is

not as accurate.

j. The difference in voltage between the operation

of the upper set of contacts and the lower set is

increased by slightly increasing the air gap

between the armature and center of core and

decreased by slightly decreasing the air gap. See

Figure 22 for changing the voltage regulator air

gap. If it is found necessary to make this air gap

adjustment, it will be necessary to recheck the

voltage setting of both sets of contacts.

C. FIELD RELAY

NOTE: Three checks are required on

the field relay: (1) air gap, (2) point

Figure 26.

opening, and (3) closing voltage.

2. Point Opening: Measure the opening between

1. Air Gap: With the regulator removed from the

the points, and adjust by bending the armature stop.

vehicle, check the air gap with the points just touching.

(Fig. 26)

(Fig. 25) If adjustment is necessary, carefully bend the

flat contact support spring.

3. Closing Voltage: The closing voltage of the field

relay may be checked as follows:

a. Connect a 50-70 ohm variable resistor and a

voltmeter to the adapter.

B-70