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Maintenance and Repair
4.3.
Troubleshooting will be aimed at determining whether the unit is defective and needs to
be returned to the factory for repair. The symptoms will be those for a motor/tach system.
Table 4-1.
Troubleshooting
Symptom
Amplifier
shuts
down
with fault indication
Amplifier
shuts
down
with no fault indication
4-2
Troubleshooting
Possible Cause
- Overcurrent trip
- Abnormal input voltage
- Low level power supply
voltage abnormal
- Excessive load
regeneration
- Open fuse F1
- Open fuse F2
- Defective amplifier
Aerotech, Inc.
6020HRJ/8030J User's Manual
Procedure
If the fault was due to overcurrent, the amplifier must
be reset with the switch. Besides a direct output to
ground, or output to output short, overcurrents can be
caused by:
•
defective motor commutator,
•
commutator arching to ground at high speeds,
•
an improper motor application causing control
instability.
If amplifier does not reset after pressing the reset
switch, check the AC input voltage (Section 3.3.1.).
Check the output voltage (terminal 15 (+) to 13(-)), this
voltage should be no more than 87VDC or no less than
45VDC. Check fuse F2. If external ±15VDC (terminals
11 and 12) are in use, disconnect them to verify that
there is no overload.
If the amplifier resets itself automatically following a
shutdown, check the following:
If fault is prevalent during an accelerating or
decelerating period, check AC input voltage (Section
3.3.1.). If condition seems to subside when the current
limit adjustment is increased (Section 3.4.1), the
problem may be excessive load regeneration, and the
use of a shunt regulator may be in order. If condition
subsides when the current limit level is reduced, the
problem could be poor input AC source regulation
If F1 is open (motor fuse), first verify that the fuse and
jumpers J1-J4 were in place for amplifier operation
(6020HRJ or 8030J) – see Section 3-2. An open F1
fuse may be caused by high duty cycle operation or
excessive loading.
If fuse F2 is open, the cause is usually a fault in the
amplifier's power stage. To verify this, check the
following with an ohmmeter before replacing F2:
A.
Place the (+) lead of the ohmmeter (x1 scale) on
terminal 15 and the (-) lead to terminal 16, then
17. Note ohm readings.
B.
Place the (-) lead on terminal 13 and the (+) lead
on terminal 16, then 17. Again, note readings.
C.
None of the four readings should be less than
20Kohms.
If ohmmeter polarities are not observed, low resistance
readings will be measured for a good power stage.
Version 1.1
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