Use of DC Generator for Starter Testing.

TM 9-4910-663-12

(1) It is possible to provide dc power for free running starter

tests by means of a dc aircraft type generator, driven by output shaft

(1, 3, fig 1-2) of varidrive. Cooling air for generator must be

supplied by external blower. Proceed as follows:

CAUTION

Depending upon voltage and current rating of

starter under test, it may be necessary to use

generator of corresponding output voltage. In

some instances, it will be possible to use a 24

volt generator for lower voltage starter tests by

dropping output voltage through adjustment of a

regulator, speed of generator, and setting of

starter rheostat on test stand.

(a) Install dc generator on mounting bracket and connect to

proper output shaft (1, 3, fig 1-2) by means of splined coupling and

adapter (6, 5, fig 2-9). Then, terminals of generator and its asso-

ciated regulator are connected through test stand circuitry to provide

field current control by means of FIELD CURRENT 0-5 AMPS (MAX) control

(R27, fig 2-2). Connect generator (+) to STARTER INPUT binding post

(fig 2-3) and generator (-) to GENERATOR G- binding post. A jumper

link must be installed between REGULATOR B- binding post and REGULATOR

G- binding post. Install a jumper between starter input and GENERATOR

G+ binding post.

NOTE

Before operating generator, make certain that

POLARITY REVERSING SWITCH (S7, fig 2-2) is set to

appropriate position.

(b) Perform free running test in same manner as described

above, except with BATTERY CIRCUIT SELECTOR switch (S6, fig 2-2) set

to OFF.

NOTE

The output voltage of the dc generator may best be

controlled by controlling the field current by use

of the field rheostat and operating the generator

at some speed below base speed. Since final adjust-

ment of voltage and speed may be necessary when the

generator is under load, care should be exercised

to prevent ceiling volts and specified field current

being exceeded when load is removed. FIELD CURRENT

0-5 AMPS (MAX) control (R27, fig 2-2) is rated at 5

amperes; therefore, DC AMMETER FIELD CURRENT meter

2-46