75-, and 100-ampere loads on the system.
Note. -
The voltage should remain between 27.5 and 28.5 volts. If it does not,
the regulator is unserviceable and should be discarded.
(5) If the regulator performs as stated, it is considered serviceable
and can be prepared for issue to a user.
(6) Discontinuing the test.
(a) Turn all rheostats fully counterclockwise.
(b) Turn all loads off.
(c) Reduce the test stand speed to 1,000 RPM.
(d) Stop the test stand main drive motor.
(e) Turn all remaining switches to the OFF position.
(f) Remove all leads and store in proper compartments.
8. SUMMARY. In this lesson we have discussed in detail the testing of the 60-
ampere generator and the 100-ampere regulator with the 500-ampere test stand. In
preparation, the test stand meters were electrically zeroed, the switches and
controls were preset, and the varidrive operated throughout its range.
a. Direct driven and pulley driven generators can be tested on the stand.
The speed of the generator determines what driving head is used. Normally, the low
speed driving head will suffice for most generators.
b. The pulley driven generator requires the use of the CAL PULLEY position
of the tachometer selector. You were shown how to calibrate the tachometer in this
position so that the proper pulley speed is visually indicated.
c. Detailed tests were discussed and now you should understand that
alternators can be tested without regulators. Also, if an alternator does not have
an internal rectifier, one must be included in the alternator test to properly load
it.
d. The regulator tests included a relay pull-in test and its function to
regulate the output voltage to specified limits. Understanding the principles
presented here will greatly aid you and improve your abilities with the use of the
500-ampere test stand. Successful completion of the exercise questions will verify
your understanding and reinforce the material presented.
Note. -
Refer to the exercise instructions presented in lesson 1.
EXERCISE
46.
What is done first when preparing the 500-ampere test stand for
operation?
a.
Calibrate the CAL PULLEY
b.
Check the battery voltages
c.
Mechanically zero the meters
OS 010, 4-P19
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