Mount sensor of thermal recorder

TM 9- 2920- 224- 34&P

OPERATIONAL TESTING OF THE GENERATOR - CONTINUED

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d. Before making test connections, flash generator field to ensure proper residual polarity at pole shoes as

follows:

1) Connect a temporary jumper lead to A terminal (4) on generator (5) and to positive (+) terminal (6) of a

24--volt battery (7).

2) Connect a temporary jumper lead to negative (--) terminal (8) of 24--volt battery (7). Hold other end of this

lead against E terminal (9) of generator for 4 to 6 seconds.

3) Remove temporary jumper leads from battery (7) and generator terminals (4) and (9).

e. Mount sensor of thermal recorder (10) on stator housing (11) of generator (5).

Connect generator (5) to a 24--volt battery (7), with a voltage regulator (12) [containing a reverse--current

relay] and ammeter (13) in circuit.

g. Connect voltmeter (14) to generator terminals B (15) and E (9) [E is negative].

h. Connect ammeter in series circuit from battery positive terminal (6) to generator B (15) terminal.

A1,=AMMETER -- 0--300 A

A2=AMMETER -- 0--1, 0--10 SCALES

R=VOLTAGE REGULATOR

T = THERMAL RECORDER

(Operational Test Setup)

Perform following test routine in the sequence given. If generator fails to meet any test requirement, stop

testing and repair generator as necessary before resuming test routine.

CAUTION

Remote air supply for generator (11642898) or electrical

power to fan motor for generator (10889713) must be on

during operational testing.

1) Start generator test stand and allow generator to run until it shows no more than a 2 F temperature rise

in five minutes.

2) With generator hot, operate for five minutes at 8000 rpm with field circuit open. During this period the

temperature should rise to a minimum of 150F.

3) With voltage regulator connected to generator, operate it self--excited at 6500 rpm, 30 volts and no load.

Record field current, condition of commutation, and frame temperature. The shunt field current must not

be less than 0.81 amperes and commutation shall be between what is commonly known as "black" (no

spark) and "pin--point" (slight sparking along trailing edges of brushes).

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