Figure 5-6. Voltage sensing module, removal and installation.

TM 5-6625-2691-13&P

TS 025342

Figure 5-6. Voltage sensing module, removal and installation.

of this module. With all wind and heat switches

this situation, the sensing module will allow the

closed, terminals 4 and 5 are connected together.

power transistor to conduct; thus pulling-in the

If any of these switches open for a period greater

power contactor (Kl). If the test set is incorrectly

than (5) seconds the power transistor will cease to

programmed for the level of a.c. input test voltage,

conduct causing power (contactor (K1) to drop-out.

the power transistor will not conduct and power

c. Removal. Refer to figure 5-6 and remove the

contactor (K1) will not pick-up. The Model A427B

voltage sensing unit.

Voltage Sensing Module also requires that all air

d. Installation. Refer to figure 5-6 and install

flow switches and over heat switches are closed to

the voltage sensing unit.

sustain unit operation. All of these switches are

series wired and connected across terminal 4 and 5

Change 1

5-7