b. Remember, as a supervisor, the responsibility for both men and equipment
is yours. You must by observation assure yourself of equipment condition. You
must check the state of training within your organization and arrange for
additional training experiences to keep your personnel informed. The supervisor
must stress the applicability of the general inspection task to all items of
organizational equipment. Performance of this task will materially reduce the cost
of maintenance and equipment downtime.
c. The primary function of preventive maintenance is to prevent breakdowns
and therefore the need for repair. Time intervals are based on normal operations.
A month, for example, is defined as approximately 30 calendar days of 8-hour-per-
day operation. If equipment is operated 16 hours a day, the monthly preventive
maintenance checks and services should be performed at 15-day intervals.
Adjustment of maintenance intervals must be made to compensate for any unusual
operating conditions.
2.
ARMATURE TEST SET MAINTENANCE.
a. Maintenance personnel perform a wide variety of tests on starter and
generator armatures using the armature test set (fig 1). The test set operates on
115-volt, 60-hertz power and is housed in its own steel case. There are three
basic circuits in the test set: growler circuit, ammeter circuit, and test lamp
circuit.
b. A primary coil and a portion of the iron of a transformer form the
growler circuit. Positioning the armature under test completes this magnetic
circuit. Passing an alternating current through the growler primary sets up an
alternating magnetic field around the armature under test. This approximately
reproduces the magnetic effect under which the armature normally operates. Under
these simulated conditions the repairman can perform the short test, open test, and
ground test on armatures.
c. The ammeter circuit is activated by induced current generated
in the
armature being tested on the growler circuit. The ammeter indicates the
flow of
current through each armature coil in relation to the other coils as the
armature
is slowly rotated. Reversed coils, .open circuits, and incorrect number
of turns
can be located by observing the ammeter indications.
d. The test lamp circuit is used in testing brush holders for grounds,
armatures for grounds, and field coils for grounds and open circuits. The lamp is
powered directly from the powerline. Test probes are connected to the lamp by
leads and are used to complete the circuit when performing tests.
e. The armature test set can be used to magnetize or demagnetize tools and
other iron objects. 'Manufacturer's instructions must be followed closely to avoid
damage to the test set during magnetizing or demagnetizing operations.
f. Maintaining the armature test set is an easy task. So easy that there
is a tendency to neglect it. Supervisors must insure that the Job is being done by
making occasional observations of the equipment. The operator should check the
equipment for completeness and general condition daily. Exterior surfaces and
receptacles must be clean and undamaged. The meter glass should be clean and
unbroken. The meter must be static free and properly zeroed. During operation
switches are checked for proper mechanical action and the operator must be alert
for abnormal indications.
OS 010, 8-P2
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