Figure 5-6. Low-inertia motor test circuit schematic diagram.

TM 11-6625-2843-14

in the stators of transmitter B201 or the control

b. When the rotor of transmitter B201 is displaced, a

transformer and, therefore, the input to the ser-

signal is induced in the transmitter stator and this sig-

voamplifier is at null. The dial reading of the indicator

nal is transmitted to the stator of the control

is then checked for correspondence with the setting of

transformer. A magnetic field is built-up across the

the transmitter dial.

stator which induces a voltage across the rotor of the

c o n t r o l transformer. This voltage is amplified by ser-

5-8.

Low-Inertia

Motor

Test

Circuit

voamplifier A201 and applied at a suitable level to the

NOTE

variable-phase winding of the low-inertia motor. The

The low-inertia motor is part of a servoed in-

motor drives the rotor of the control transformer

dicator. The low-inertia motor test circuit

through a gear train through a proportional angle of

(fig. 5-6) is used to perform a direction test,

rotation. At this position, no voltages are induced with-

and a torque and friction test.

Figure 5-6. Low-inertia motor test circuit schematic diagram.

motor rotation. With MOTOR VOLTS switch S201 at

a. Direction Test. The direction test is enabled by

FXD 26 volts are applied to the fried-phase motor

TEST SEL switch S203 at MOTOR, and MOTOR

windings and to the VTVM binding posts. The FXD

VOLTS switch S201 at FULL. With this teat setup, 26

control may then be adjusted to the rated value of the

volts are applied to the fixed- and variable-phase wind-

fixed-phase motor winding. Similarly, with the

ings of the low-inertia motor. Capacitor C201, in the

M O T O R VOLTS switch at VAR VAR control R203

variable-phase line, introduces a 90-degree phase shift

adjusts the rated value of the variable-phase motor

between the two windings. The motor rotates and the

winding.

direction of motor rotation may be observed.

b. Torque and Friction Test. The torque and friction

5-9. Indicator Test Circuit for Transmitters

test is enabled by TEST SEL switch S203 at MOTOR

The indicator test circuit for transmitters (fig. FO-1) is

enabled by TEST SEL switch S203 at TRANS and

and is used to measure the voltage required to start

5-7