TM 1-1520-240-MTF
4-45
screw changes N1 approximately 1% PTIT
approximately 25_C and torque 5 - 6%. If the
recorded N1 is acceptable, but the recorded
PTIT is lower than it should be according to
11a, a resistance check of the PTIT harness
should be performed. If the PTIT indicating
system is OK the engine is acceptable.
U. DIFFERENTIAL CURRENT PROTECTION CIRCUIT
CHECK
1-44.
Reference:
TM 55-1520-240-23
Perform this check whenever maintenance has been
performed on a generator, or a generator control unit, a
current transformer or the wiring between these units.
Perform the check as follows:
1. Set the following switches to the specified
positions:
a. HEATER — VENT BLOWER ONLY.
b. CPLT, CTR, and PLT WINDSHIELD
ANTI-ICE — ON.
c. CPLT and PLT SLT-FIL — ON.
d. FUEL PUMPS — ALL ON.
2. GEN 1 switch — OFF. Check NO. 1 GEN OFF
caution light is on and NO. 2 GEN OFF caution
light is out.
3. GEN 1 switch — ON. GEN 2 switch — OFF.
Check NO. 1 GEN OFF caution light is out and
NO. 2 GEN OFF caution light is on.
4. GEN 2 switch — ON. Check both GEN OFF
caution lights are out.
5. HEATER, WINDSHIELD ANTI-ICE, SLT-FIL,
and FUEL PUMPS switch — Set as desired.
