TM 9-4910-663-12
generator gradually until rated load is reached, and vary generator
speed throughout generator speed range while observing DC VOLTMETER
OUTPUT VOLTAGE meter (M2, fig 2-1) and TACHOMETER RPM meter M1
(22) Using MASTER LOAD DISCONNECT switch (S8, fig 2-2) shock
test generator and regulator while noting regulated voltage. Set
MASTER LOAD DISCONNECT switch to OFF, then to ON to shock load.
(23) Increase loading slowly and observe drop off in voltage
indicated on DC VOLTMETER OUTPUT VOLTAGE meter (M2, fig 2-1) when cur-
rent limiter comes into play. Also note lack of current increase with
increasing load.
(24) Decrease load to zero by setting all LOAD SELECTION switches
(S17 through S24, fig 2-2) to OFF and set MASTER LOAD DISCONNECT
switch (S8) to OFF.
(25) Set BATTERY CIRCUIT SELECTOR switch (S6, fig 2-2) to OFF.
(26) When required by manufacturer's test procedure, perform
differential voltage and reverse current tests as follows:
(a) Set FIELD CIRCUIT switch (S32, fig 2-2) to MANUAL position
and adjust generator voltage on DC VOLTMETER OUTPUT VOLTAGE meter (M2,
fig 2-1) to within 2 to 4 volts of battery voltage by rotating FIELD
CURRENT 0-30 AMPS (MAX) control (R26, fig 2-2) in clockwise direction.
Then set BATTERY CIRCUIT SELECTOR switch (S6) and MASTER LOAD DISCON-
NECT switch (S8) to ON position.
(b) Press and hold MILLIVOLT METER MILLIVOLT DROP PRESS TO
READ switch (S34, fig 2-1). Increase generator voltage very slowly,
using FIELD CURRENT 0-30 AMPS (MAX) control (R26, fig 2-2), while
observing MILLIVOLT METER MILLIVOLT DROP meter (M4, fig 2-1). Voltage
should increase and then decrease to zero when cutout relay closes.
Highest voltage attained is differential voltage. Release MILLIVOLT
METER MILLIVOLT DROP PRESS TO READ switch (S34).
(c) Slowly decrease generator voltage with FIELD CURRENT 0-30
AMPS (MAX) control (R26, fig 2-2) while observing DC AMMETER LOAD &
STARTER OUTPUT CURRENT BATTERY CHARGE CURRENT meter (M3, fig 2-1).
Current should decrease, then indicate a reverse reading, and then
come back to zero when cut-out relay opens. Maximum reverse current
attained is reverse current reading for particular generator under
test.
(d) Set BATTERY CIRCUIT SELECTOR switch (S6, fig 2-2) to OFF.
(e) Set FIELD CIRCUIT switch (S32, fig 2-2) to REGULAR posi-
This will give regulated voltage, controlled by regulator.
tion.
(f) Set MILLIVOLT METER MILLIVOLT DROP RANGE switch (S16, fig
2-39