TM 9-4940-549-14&P
(e) If voltmeter indication is as specified, proceed with voltage
regulator, alternator output, and voltage protector test as
outlined in step (9) below,
(7) Test for faulty alternator voltage regulator as follows:
(a) Remove screws and cover assembly.
(b) Disconnect voltage regulator by disconnecting and tagging
the red, green, and black leads.
(c) Disconnect and tag the blue and yellow output leads.
(d) Install a jumper wire from the GND terminal to brush termi-
nal as shown in figure 7-13.
(e) Install alternator in test circuit as shown in figure 7-13.
NOTE
A means of rotating the alternator at
2,000 to 3,000 rpm must be provided.
This test can be performed with the
alternator installed on an operational
set and operating the set at rated fre-
quency.
(f) With the alternator rotating at 2,500 rpm, the voltmeter
should indicate 24 to 28 volts and ammeter should indicate
32 to 34 amperes.
(g) If the alternator tests satisfactorily, this indicates that the
voltage regulator was faulty.
(h) If the alternator does not test satisfactorily, this indicates
that the voltage regulator is good and the trouble is on
the alternator.
(i) If the regulator is faulty, remove the jumper and install a
new regulator and cover assembly using the tagged identifica-
tion as a guide.
(8) Conduct field current test as follows:
Rheostat must be set in maximum resis-
tance position to protect the ammeter
in the event the field circuit is short
circuited.
(a) Install the ammeter in test circuit as shown in figure 7-14.
