cuit to the battery circuitry of the test stand,
tected by setting the switch in the "PH1, PH2,"
permitting the voltage condition of the batteries
and "PH3" positions and observing the amper-
(fig. 9) to be
indicated on the dc
voltmeter (5).
age reading on the ac ammeter (6). Ampere
To take the battery voltage reading on the dc
differential of more than ten amperes between
voltmeter, turn the dc voltmeter circuit selector
any two settings indicates unbalanced phase
conditions (par. 16).
switch (23) to the "BAT VOLTS" position and
place the battery switch (41-B) in the "ON"
35. Ac Ammeter Range Selector Switch
position. Always place the battery switch in the
"OFF" position after voltage reading is taken,
SELECTOR)
this will allow voltage to be indicated on the
The ac ammeter range selector switch (25),
dc voltmeter when performing tests on dc sys-
located directly under the ac ammeter (6) near
tems and ac/dc systems, d below.
the right hand end of the main control panel,
c. " V A R I A B L E VOLTS" Position. The
is a 3-position (center position open circuit),
"VARIABLE VOLTS" position connects the dc
3-pole, 2-deck, rotary type selector switch. It
voltmeter (5) circuit to the dc variable volts
is connected in series with the ac ammeter phase
negative and positive binding posts (28-C).
selector switch (par. 34). The switch can be
When the two binding posts are connected to
set to acquire 100 and 400 ac ampere ranges
the dc system under test and with the variable
on the ac ammeter (6) for testing ac/dc sys-
external volts ON-OFF switch (28-A) in the
tems (par. 16), by setting the switch in the
"ON" position the variable voltage applied
"100 (X1)" and "400A (X4)" positions.
(par. 57) will be indicated on the dc voltmeter.
d. "RECT GEN" Position. T h e " R E C T
36. Ac Voltmeter Range Selector Switch
GEN" position connects the dc voltmeter (5)
(Designated as AC VOLTMETER RANGE
c i r c u i t to the G+ and G- generator input
SELECTOR)
binding posts (13-A and 13-B, fig. 15) when
The ac voltmeter range selector switch (26),
t e s t i n g dc systems and to the D- and C+
located directly under the ac voltmeter (7) near
rectifier input binding posts (42-B and 42-D,
the right hand end of the main control panel,
fig. 16) when testing ac/dc systems permitting
is a 3-position (center position open circuit),
voltage readings to be indicated on the dc volt-
1-pole, 1-deck, rotary type selector switch. It
meter for these two systems.
is connected in series with the ac voltmeter
phase selector switch (par. 37). The switch
e. "EXT VOLTS" Position. T h e " E X T
can be set to acquire 25 to 50 ac volt ranges on
VOLTS" position connects the dc voltmeter (5)
the ac voltmeter (7) for testing ac/dc systems
circuit to the external dc voltmeter positive and
( p a r . 17), by setting the switch in the
negative binding posts (29) and permits the
"25V (X1)" and "50V (X2)" positions.
use of the dc voltmeter for measuring posts
(29) and permits the use of the dc voltmeter
37. Ac Voltmeter Phase Selector Switch
for measuring dc voltage from a source external
(Designated as AC VOLTMETER PHASE
SELECTOR)
34. Ac Ammeter Phase Selector Switch
The ac voltmeter phase selector switch (27),
located directly under the ac voltmeter (7) on
SELECTOR)
the right hand end of the main control panel,
The ac ammeter phase selector switch (24),
is a 5-position (position between marked posi-
tions open circuit), 2-pole, 1-deck, rotary type
located directly under the ac ammeter (6) near
selector switch. It is used to place the circuitry
the right hand end of the main control panel,
of the ac voltmeter (7) in the circuit of the
is a 5-position (position between marked posi-
phase of an ac/dc system being tested. Balance
tions open circuit), 3-pole, 2-deck, rotary type
phase condition of an ac/dc system can be de-
selector switch. It is used to place the circuitry
tected by setting the switch in the "T1-T2,"
of the ac ammeter (6) in the circuit of the
"T1-T3" and "T2-T3" positions and observing
phase of an ac/dc system being tested. Balance
the voltage reading on the ac voltmeter (7).
phase condition of an ac/dc system can be de-