system u n d e r g o i n g t e s t w i t h t h e s w i t c h
68. Field Ammeter
DC AC/DC Switch (Des-
(53) (par. 62) and switch (54) (par. 63).
ignated as DC AC/DC)
Note. The 250-ohm field current rheostat (55) will
The field ammeter dc ac/dc switch (59), lo-
h a v e no control on the output of a third brush gen-
cated near the top left hand end of the main
erator which is self-regulated for the generator output.
control panel is a 2-position (on-off), single-
When testing this type generator, place the switch (53)
i n the center (OFF) position (par. 62).
pole, single-throw, 25-ampere, 30-volts dc,
t o g g l e switch. The switch is used to connect
65. 250-Ohm Field Current Rheostat Fuse
Holder (Designated as FUSE)
posts (12, fig. 15) by placing the switch in the
The 250-ohm field current rheostat fuse
" A C / D C " position or to connect a dc system
holder (56), located in the center bottom of the
to the generator input binding posts (13, fig.
m a i n control panel contains a 5-ampere fuse
15) by placing the switch in the "DC" position.
which is held in the holder by a threaded cap.
To remove the fuse for inspection or replace-
69. Battery Charge Rate Read Switch (Des-
m e n t turn the cap to the left until free. The
ignated as BATTERY CHARGE RATE
fuse is held in the cap by a friction fit sleeve
READ 0-50 AMPS)
and can be removed by firmly gripping it and
The battery charge rate read switch (60),
pulling outward on the fuse. The fuse provides
located near the top left hand end of the main
a n overload protection for the 250-ohm field
c o n t r o l panel is a 2-position (none-monetary
current rheostat (55) circuitry in case the field-
on) two-pole, double throw, 25-ampere, 30-volt
c u r r e n t - d r a w exceeds 5-amperes when testing
dc, toggle switch. The switch is used to activate
a dc generator with or without a generator reg-
t h e load dc ammeter (1) when charging the
ulator or generator control box in the circuit.
batteries in the test stand while using the bat-
t e r y charger. Holding the switch lever up to
"READ" position will indicate the current out-
as LOAD SWITCHES 100-50)
put of the battery charger on the load dc am-
The 100-50 fixed load switches (57), located
meter (1) and releasing the lever to the down
in the center top of the main control panel con-
p o s i t i o n will disconnect the battery circuitry
sists of four 100-ampere at 30 volts dc, single-
to the load dc ammeter (par. 98).
t h r o w , toggle switches. Each load switch is
used to apply a fixed current load of 0-50 am-
70. Starter Test Load Disconnect Switch (Des-
ignated as STARTER TEST LOAD DIS-
p e r e s on units undergoing test with an oper-
ating voltage rating of 15 volts and below and
a fixed current load of 0-100 ampres on units
The starter test load disconnect switch (61),
with an operating voltage rating above 15 volts
located on the top left hand end of the main
control panel, is a 2-position (on-off), single-
to 30 volts. The switches may be used individ-
pole, single-throw, 25-ampere, 30-volt dc,
u a l l y or in conjunction with the other load
toggle switch. The switch is used in conjunc-
s w i t c h e s (37), (38), (39), and (40).
t i o n with the load switches (37), (38), (39),
(40), and (57) for placing ampere loads on dc
67. Tachometer Indicator Calibrating Poten-
tiometer (Designated as CAL POT MAX)
by throwing the switch lever up to the "ON"
The tachometer indicator calibrating poten-
position to apply ampere loads and to the down
tiometer (58), located near the center top of the
" O F F " position to disconnect the loads. It is
main control panel, is a 50 K (kilohm), 4-watt
wire-wound potentiometer used in conjunction
(cranking motors) undergoing test by connect-
ing the starter carbon rheostat (5, fig. 15) in
the circuit of the starter (par. 94) by placing
brating potentiometer switch (19) for calibrat-
the switch in the up "ON" position or discon-
i n g the tachometer indicator circuitry. Refer
the down "OFF" position.