TM 9-4910-663-12
(15) AC VOLTMETER OUTPUT VOLTAGE SELECT Switch (S28, fig 2-1).
This switch, which has three positions designated T1-T2, T1-T3, and
T2-T3, is used to connect the AC VOLTMETER OUTPUT VOLTAGE meter cir-
cuits-for measurement of desired ac phase voltages.
(16) AC VOLTMETER OUTPUT VOLTAGE RANGE Switch (S27, fig 2-1).
This switch has two positions: X1 (25 volts), direct to the corre-
sponding meter, and X2 (50 volts), to an external multiplier resistor
mounted on the printed circuit board. The switch provides a means of
selecting either of the two ranges of the AC VOLTMETER OUTPUT VOLTAGE
meter.
(17) AC AMMETER OUTPUT CURRENT SELECT Switch (S25, fig 2-1).
This switch connects the AC AMMETER OUTPUT CURRENT meter circuit to
the desired phase (T1, T2, or T3) to be monitored, and maintains a
shorted condition across the secondaries of the other two phase cur-
(18) AC AMMETER OUTPUT CURRENT RANGE Switch (S26, fig 2-1).
This switch has two positions: X1 (100 amperes) and X5 (500 amperes).
The switch provides a means of selecting either of two ranges of the
(19) TACHOMETER RPM SELECT Switch (S36, fig 2-1). This switch
is a selector switch for the TACHOMETER RPM meter. The DIRECT DRIVE
position is used when the unit undergoing test is a direct driven
unit, or a pulley-driven unit with a 1:1 pulley ratio with the test
stand. The CAL PULLEY position is used when the unit undergoing test
is a pulley-driven unit with a pulley diameter that differs from that
of the test stand.
(20) TACHOMETER RPM PULLEY CALIBRATION Control (R35, fig 2-1).
This control is used to calibrate the TACHOMETER RPM meter circuit to
provide the correct speed indication for pulley-driven units having a
pulley diameter that differs from that of the test stand. Use of this
(21) DC VOLTMETER OUTPUT VOLTAGE SELECT Switch (S11, fig 2-1).
This switch provides a means for using the DC VOLTMETER OUTPUT VOLTAGE
meter for measurement of dc voltages at different points in the test
circuit, as follows:
(a) The BAT position connects the meter circuit to the B+ bus
and the battery minus bar, when the MASTER LOAD DISCONNECT switch is
in the ON position.
2-4