are indicated on the load dc ammeter
d. Test Procedures.
(1). The dc voltmeter (4) should in-
dicate approximately 28 volts and the
(par.
f i e l d dc ammeter (2) not more than
(1) The position of the switches and con-
7 . 5 amperes (refer to paragraphs 74
trols pertinent to this test are listed in
a n d 75 if no amperage reading can
b e obtained on the load dc ammeter
t h e s e items in positions indicated in
(1)).
of the table before tests are
column
started.
N o t e . Observe the dc voltmeter (4) and
b r i n g the generator voltage up to approxi-
(2) P l a c e the battery switch (20) in the
mately 20 volts reading on the dc voltmeter
" O N " position and turn the dc volt-
r a p i d l y , and evenly, using the 40-ohm field
m e t e r circuit selector switch (9) to
c u r r e n t rheostat (16), then proceed slowly
until 300 amperes are indicated on the load
the "BAT VOLTS" position to deter-
d c ammeter (1), (7) above.
m i n e whether the battery voltage of
(8) Turn the 40-ohm field current rheo-
the test stand is the same as the volt-
s t a t (16) in the fully counterclock-
age of the system under test. Correct
w i s e direction and the speed control
voltage is 24 volts which will be indi-
h a n d l e (22) partially counterclock-
cated on the dc voltmeter (4). If the
wise until the varidrive assembly
reading is less than 24 volts recharge
b a t t e r i e s (par. 98). It is also advis-
s p e e d is reduced to -speed. Stop
able to check the batteries with a hy-
the varidrive assembly by depressing
d r o m e t e r for specific gravity (refer
t h e stop button (21-C) on the drive
t o TM 9-6140-200-15).
c o n t r o l (21). If the generator per-
forms as specified in (7) above, next
Note. The safety clip (21-B) must be off
t h e stop button (21-C) to perform the bat-
t e s t in (9) below can be performed,
t e r y check in (2) above. Do not push the
o t h e r w i s e , generator is unserviceable
s t a r t button (21-A) as the varidrive assem-
a n d will require repairing. Leave all
bly need not be running for this test.
leads, connecting links, switches, and
(3) Place the battery switch (20) in the
c o n t r o l s remain as specified at this
"OFF" position and turn the dc volt-
p o i n t and continue with test in (9)
m e t e r circuit selector switch (9) to
b e l o w if generator is not unservice-
the "RECT GEN" position.
able.
(4) Start the varidrive assembly by slid-
(9) T e s t for interpole and compensating
ing the safety clip (21-B) off the stop
w i n d i n g shorts as follows:
b u t t o n (21-C) and depress the start
button (21-A) (do not depress the
t o r switch (8) in the "10V (X1)"
start button more than 10 seconds) to
p o s i t i o n and the dc voltmeter cir-
s t a r t the varidrive assembly.
cuit selector switch (9) in the "EXT
(5) T u r n the speed control handle (22)
VOLTS" position.
slowly clockwise until 3,000 rpm are
(b) C o n n e c t the external dc voltmeter
indicated on the tachometer indicator
positive (red) binding post (29, fig.
meter (3).
(6) Place three of the fixed load switches
post (10-E, fig. 15) and connect the
(12-A) in the "ON" position (be sure
external dc voltmeter negative
the starter test load disconnect switch
( b l a c k ) binding post (29, fig. 16)
( 1 0 ) is in the "ON" position before
to the "D" generator input binding
load switches are turned on).
post (13-C, fig. 15) of the test
(7) T u r n the 40-ohm field current rheo-
s t a n d using two test leads 38425
stat (16) clockwise until 300 amperes
(fig. 74).
93
