1. Referring to foldout 5, turn the tachometer pulley
calibration control (7) to its counterclockwise position and the selector switch
(8) to the DIRECT DRIVE position.
2. Start the varidrive assembly and preset the RPM of the
driving pulley. This is done by increasing the drive speed control (42) so that
tachometer RPM is indicating at a reference point on the meter face.
Example:
If the UUT is mounted on the low speed head, select a reference point on
the lower scale in the vicinity of 2,000 RPM. If mounted on the high
speed head, select a point on the upper scale in the vicinity of 6,000
RPM.
3. Determine the speed of rotation (RPM) of the pulley on the
UUT by using the following equation:
UUT pulley RPM =
(Test stand RPM X 4) D
Where D =
diameter of UUT's pulley
Example:
Test stand RPM
= 2,000 RPM, as indicated on the tachometer.
D = 3 inches
= diameter of UUT's pulley.
UUT pulley RPM
=
(2,000 X 4) 3
= 8,000 3
=
UUT pulley RPM
= 2,666
4. To calibrate the tachometer for the RPM indicated in the
example, simply turn the selector switch (8) to the CAL PULLEY position.
5. Turn the calibration control (7) clockwise until the scale
on the tachometer reads 2,666 RPM.
6. Now, during testing, the drive speed control (42) can be
adjusted and the tachometer will indicate the true RPM of the pulley driven unit
under test.
5. TESTING 60-AMPERE SYSTEM. As we said before, testing of the 60-ampere system
is with or without the voltage regulator. The first test to perform is the test
without the regulator. If this test does not perform properly, then disassemble
the generator and test to find malfunctioning components of either the stator,
rotor, or rectifying diodes.
a. Regulator removed. The regulator must be removed from the generator to
perform this test. Also, the internal connector, which connects to the regulator,
has open circuits. These circuits must be Jumped so operation of the field circuit
in the rotor may be controlled from the test stand. Figure 8 shows the connector
and jumper wires which are connected between terminals 1 and 5 and also 2 and 3.
OS 010, 4-P11
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