Rockwell Automation MinPak Plus DC Drives Kits - Manual (Page 43)

42
SYMPTOM PROBABLE CAUSE RECOMMENDED PROCEDURES
8. Drive motor
does not
run with M
contactor
picked up
and SPEED
pot properly
operating.
(Continued )
Regulator Module susĆ
pected because no output
reading at A1, A2.
V Test the Regulator Module for firing pulses as described below.
V Turn the POWER ON/OFF circuit breaker to OFF. Open the main disconnect.
V Locate the 50mf capacitor at R27Ć43 and put the voltmeter (-) lead to R27.
V Locate the four diodes on the Gate Coupling board near the words Gate
Coupling Card." Connect the (+) meter lead to the anode ➀ of the leftĆmost
diode (D1). Put the voltmeter on a low aĆc volt scale.
V Restore aĆc power to the controller. Put FORWARD/REVERSE switch in
REVERSE.
V Place the START/STOP switch in the START position.
V Turn the SPEED pot up to about 5.
V The reading on the VOM should be about -0.7 VAC.
V Turn the START/STOP switch to STOP and remove aĆc power.
V Repeat this test with (+) meter lead on the next diode to the right (D2).
V Repeat the test with FORWARD/REVERSE in the FORWARD position and the
(+) meter lead on each of the two rightĆmost diodes (D3 and D4).
V If any of the four readings cannot be obtained, replace the Regulator Module.
Power Cubes suspected
because no output readĆ
ing at A1, A2.
V Establish that the Power Cubes are receiving pulse inputs at the connector
on the Regulator Module. (Refer to the 2nd item just above, Regulator
Module suspected.)
V If the Power Cubes are receiving pulses yet there is no reading across A1
and A2, determine that the main contacts on the M contactor are closing.
V In order to check the contacts, replace the drive motor with a light bulb on
the armature wiring at 1TB. (On 230 VAC controllers use two light bulbs in
series.)
V If the light does not light, replace the Power Cubes.
9. Drive motor
does not
run with M
contactor
picked up
and SPEED
pot properĆ
ly operatĆ
ing.
(Use this
procedure
only if conĆ
troller has
optional
Test Meter
Adapter
Kit.)
No gate firing pulses. V Turn off power to the controller at the POWER ON/OFF circuit breaker and
the main disconnect.
V Connect a voltĆohmmeter lead to test pin 356 on the Test Meter Module.
V Connect the second lead to test pin 817. Put the FORWARD/REVERSE
switch in the REVERSE position.
V Restore power to the controller.
V Place the START/STOP switch in the START position.
V On the VOM's +10 VDC scale, an increase of approximately +1 VDC should
be noted.
V Turn off power to the controller.
V Reconnect the VOM to test pins 356 and 816. Put the FORWARD/REVERSE
switch in the FORWARD position.
V Put the START/STOP switch in the START position.
V On the VOM's +10 VDC scale, an increase of approximately +1 VDC should
be noted.
V If voltage readings increase, the Power Cubes are receiving pulses to the
SCRs.
V Make a last check of wiring to the Power Cubes.
V If wiring is correct, replace the Power Cubes.
10. Motor runs
but current
peaks too
high.
One phase not firing. V Perform the procedure for Symptom 8, Regulator Module suspected
because no output reading at A1, A2. If all pulses are present, one or more
Power Cubes are faulty.
➀ The anodes are the leads nearest the pulse transformers (also, the leads without the l.D. white circle.)
DANGER
THE PROCEDURE DESCRIBED HERE IS PERFORMED WITH LIVE AĆC
VOLTAGE APPLIED TO THE CONTROLLER. USE ONLY ONE HAND TO
APPLY VOM LEADS/PROBES. KEEP YOUR OTHER HAND BEHIND YOU
AT ALL TIMES. DO NOT HOLD ONTO THE CONTROLLER FOR SUPĆ
PORT. PERSONAL INJURY MAY RESULT IF THESE PRECAUTIONS ARE
NOT TAKEN.