position (1) (a) above, then place
(a) Place the 100-50 fixed load switch
the 100-50 fixed load switch (17-A)
( 1 7 - A ) i n t h e " O F F " position
in the "ON" position. If the voltage
(d) above, and then place the
drop is more than 0.5 volt (repeat
50-25 fixed load switch (17-B) and
placing fixed load switch on and off
the 25-12.5 fixed load switch (17-C)
several times), remove load and re-
both in the "ON'' position to obtain
duce speed of the varidrive assembly
a 75 ampere load.
to 3,200 rpm by turning the speed
(b) Reduce the varidrive assembly speed
control handle (24) counterclock-
by turning the speed control handle
wise.
( 2 4 ) counterclockwise until the
(d) Turn the contact screw assembly
voltage reading on the dc voltmeter
counterclockwise (loosen locking
(4) is within 26.0 to 26.5 volts.
screw on each side of the contact
screw first, then tighten after ad-
74) to the external dc voltmeter pos-
justment is made (fig. 58)).
itive and negative binding posts
(e) I n c r e a s e the varidrive assembly
(29, fig. 16).
rpm to 4,000 on the tachometer in-
(d) Connect the test lead from the ex-
dicator meter (3) and shock load
ternal dc voltmeter positive binding
by turning the 100-50 fixed load
post, (c) above, to the No. G+ bind-
switch (17-A) on and off to settle
ing post (10-C, fig. 15) and the test
the carbon pile of the generator (al-
lead from the external dc voltmeter
t e r n a t o r ) regulator. Adjust the
negative binding post, (c) above, to
regulator to 28 volts by adjusting
the No. F-B binding post (10-G, fig.
the 5-ohm adjustable resistor as-
15).
sembly (fig. 56) with the external
voltage adjustments (fig. 57).
tor switch (10) in the "EXT
( f ) R e p e a t (c) through (e) above at
VOLTS" position.
least three times to assure repeti-
( f ) Observe the current reading on the
tion of performance.
field dc ammeter (2) and voltage
(3) Checking voltage range.
reading on the dc voltmeter (4).
(a) Leave the battery on-off switch (22)
(g) Divide the voltage reading of the
in the "ON" position and place all
d c voltmeter (4) by the current
f i x e d load switches (17) in the
reading of the field dc ammeter (2).
"OFF" position.
The resultant should not exceed 0.5
the
assembly,
(b) Stop
varidrive
ohms.
(a) above, and remove the gen-
(2) Testing and adjustment at 6,000 rpm.
erator (alternator) from the high
the
(a) stop
varidrive
assembly,
speed driving head (4, fig. 7) and
(a) above, and remove the gen-
place it on the low speed driving
e r a t o r (alternator) from the low
head (5, fig. 7). Recalibrate the
speed driving head (5, fig. 7) and
tachometer indicator circuitry ac-
place it on the high speed driving
(b) above.
cordingly,
head (4, fig. 7). Recalibrate the
(c) S t a r t t h e v a r i d r i v e assembly,
tachometer indicator circuitry ac-
(c) above, and turn the speed
(b) above.
cordingly,
control handle (24) clockwise until
(b) Turn the speed control handle (24)
1,000 rpm are indicated on the ta-
slowly clockwise until 6,000 rpm are
chometer indicator meter (3).
indicated on the tachometer indica-
(d) Observe the voltage reading on the
tor meter (3).
d c voltmeter (4) and adjust the
(c) Place the 50-25 fixed load switch
5-ohm adjustable resistor assembly
by first turning the adjusting knob
( 1 7 - B ) and 25-12.5 fixed load
switch (17-C) both in the "OFF"
or screw (fig. 57) counterclockwise
121
