Slowly increase the speed by turn-
ing the speed control counterclock-
wise. Listen for unusual noises and
if the speed increases at a steady
rate as the speed control is turned.
Reduce the speed to its minimum
and turn the direction control
switch to the off position until the
drive motor stops. Turn the direc-
tion control switch to right hand
rotation and perform the same
checks as for left hand rotation.
Turn the direction control switch
to the off position. Perform the
above checks at 0 to 500 rpm with
the speed range selector switch in
the 0-500 position.
(3) Turn the vacuum pump switch (12)
on and plug the end of the vacuum
hose (9) by placing a finger over
the hole. Decrease the vacuum to
approximately 1 inch of mercury
on the vacuum gage (10) by turning
the vacuum pump control (13)
counterclockwise. Then turn the
control clockwise slowly and watch
the pointer on the vacuum gage.
The pointer should make approxi-
mately 1-1/2 revolutions and indi-
cate a maximum reading of about
graph 24, for instructions on how
to read the vacuum gage.
(4) Remove the finger plugging the
vacuum hose, turn off the vacuum
switch, direction control switch,
and power switch. Disconnect the
power switch on and reduce the
power cable from the power source.
speed of the stroboscope drive
shaft (23) to its lowest speed by
turning the speed control (14)
c l o c k w i s e as far as possible.