TM 9-6115-670-14&P
5-55
5.20. ELECTROMAGNETIC SAFETY RELAYS.
This task covers: a. Test
b. Replace
INITIAL SETUP
Tools
General Mechanic's Tool Kit
(Item 1, Appendix B)
Ohm Meter
Equipment Conditions
MASTER ON-OFF switch on APU control unit set
to OFF.
Air filter removed (para 4.45.).
Materials/Parts
Safety Relay
TEST
a. Perform steps a through c of REPLACE below.
b. Check for resistance between contacts 85 and 86, and 30 and 87a. Resistance should be 260
ohms +/- 10.
c. Check for an open circuit between 30 and 87.
d. Apply 24 voltages DC to terminals 86 and 87 with the positive voltage applied to 86.
e. Check for continuity between contacts 30 and 87 and check for open circuit between contacts
30 and 87a.
f. Remove 24 volts DC from contacts 85 and 86.
g. Replace electromagnetic safety relays if defective.
h. Perform steps d through f of REPLACE below.
i. Additional test procedures to be determined
WARNING
Ensure that APU DC power supply is disconnected.
Failure to observe this warning could result in severe
injury or DEATH to personnel.
WARNING
Ensure that the APU is turned off and completely de-
energized before opening generator housing.
Failure to observe this warning could result in severe
injury or DEATH to personnel.
