Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 209)

Rockwell Automation Publication 20P-UM001I-EN-P - February 2013 209
Troubleshooting Chapter 4
Drive starts but motor does not turn and no armature current
The motor does not reach commanded speed
The motor is turning in the wrong direction
Drive Symptom Action
The drive starts but there is no armature current and the motor
does not respond to a speed signal. • Verify the wiring to the analog input(s) selected for speed reference (see I/O Wiring Examples on page 80 ).
• Verify the setting(s) of switch S9 and Par 71 [Anlg In1 Config]; or S10 and Par 76 [Anlg In2 Config]; or S11 and Par
81 [Anlg In3 Config] (see DIP Switch and Jumper Settings on page 72 ).
• Verify the speed selection digital input(s) and the respective input terminal voltage(s), if used.
• Verify the analog input(s) voltage(s) displayed in parameters 1404 [Analog In1 Value], 1405 [Analog In2 Value] or
1406 [Analog In3 Value].
The drive starts and armature current is present but the motor
does not turn. • The Load may be too great for the motor and drive.
• Remove the load from the motor and test for motor rotation. If the motor rotates, then verify that the measured
armature current, using an in-line current meter or DC clamp on meter, equals the armature current feedback
value displayed in parameters 200 [Arm Current] and 199 [Arm Current Pct]. Increase the value of parameter 7
[Current Limit], 8 [Current Lim Pos] or 9 [Current Lim Neg].
• Verify that the measured motor field current, using an in-line current meter or DC clamp on meter, equals the
feedback value displayed in parameter 351 [Field Current].
• Verify that the motor nameplate value equals the value displayed in parameter 280 [Nom Mtr Field Amps].
• Measure the DC voltage supplied to the motor field. Verify that the value of parameter 374 [Drv Fld Brdg Cur]
equals the setting of DIP Switch S14.
• If the motor does not rotate with the load removed, check the motor.
• Verify that parameter 353 [Zero Torque] is not enabled.
Drive Symptom Action
The drive starts and the motor turns but does reach the
commanded speed. The load may be too great for the motor and drive.
• Remove the load from the motor and test for the correct commanded speed. If the motor reaches the commanded
speed, then verify that the measured armature current, using an in-line current meter or DC clamp on meter,
equals the armature current feedback value displayed in parameters 200 [Arm Current] and 199 [Arm Current Pct].
Increase the value of parameter 7 [Current Limit], 8 [Current Lim Pos] or 9 [Current Lim Neg].
• Verify that the measured motor field current, using an in-line current meter or DC clamp on meter, equals the
feedback value displayed in parameter 351 [Field Current].
If the motor does not achieve commanded speed continue with following tests:
• Check the speed parameter limits: parameters 2 [Maximum Speed], 3 [Max Speed Fwd], 4 [Max Speed Rev] and
122 [Spd Feedback].
• Check the analog voltage input and speed reference values: parameters 1404 [Analog In1 Value], 1405 [Analog In2
Value], 44 [Speed Ref A], 48 [Speed Ref B]
• Check the setting of switch S9 and parameter 71 [Anlg In1 Config], S10 and 76 [Anlg In2 Config] or S11 and 81
[Anlg In3 Config].
• Tune the analog input(s) using parameters 259…261 [Anlg Inx Tune] with the potentiometer set at max.
• The encoder pulse per revolution (PPR) parameter (169 [Encoder PPR]) value is too high.
• The DC Tach Scaling is incorrect or the jumpers are not properly set. Check parameter 562 [Anlg Tach Gain] and
check the setting of the DC Analog Tachometer DIP Switch S4 (see Figure 50 on page 74 ).
Drive Symptom Action
The motor is rotating in the wrong direction. The motor is incorrectly wired.
• Change the armature or field connections to the drive.
• The Polarity of the analog speed reference signal is incorrect for the required direction.
ATTENTION: If the motor is turning the wrong direction and the drive is using an encoder or DC analog tachometer for feedback and the speed feedback is
correct, then the feedback wiring must be changed. If using an encoder, then two encoder connections must be reversed (A with A-Not or B with B-Not). If
using a DC analog tachometer, then the tachometer leads must be reversed.