Pump Contactor Point Check

TM 10-3930-631-34

Figure 9-11. Charging the capacitor.

c. If capacitor charges too fast, it has lost its

Figure 9-12. Discharging the capacitor.

capacity.

d. If capacitor charges too slow, it is leaking. If it is

9-21. Pump Contactor Point Check

leaking, it will not charge to full battery voltage with a 10K

a. To help extend the lift of pump contactor, check

ohm resistor in series.

for the following:

e. Discharge capacitor as follows:

b. Check the air gap between the contactor tips. It

f. Remove the resistor from the circuit and

should not be greater than 3/8 inch (9.5 mm). Adjust

continue to charge the capacitor to full battery voltage.

contactor tips to reduce air gap, if necessary. (fig. 9 -

Then disconnect battery leads and immediately

13).

connect voltmeter and 10K ohm resistor as illustrated in

(fig. 9-12). After resistor is connected, begin timing the

discharging period with the watch. Capacitor should

discharge in 37 seconds to 14 volts ( 3 volts).

9-17