Struggling with troubleshooting and repair? Keep your equipment running smoothly by using the following guide to diagnose any trip codes. The following are some of the common errors you might encounter:
| Trip Code | Condition | Possible Cause |
| UU | DC Bus under voltage | Low AC Supply Voltage Low DC Bus voltage when supplied by an external DC power supply |
| OU | DC Bus over voltage | Deceleration rate set too fast for the inertia of the machine Mechanical load driving the motor |
| OI.AC** | Drive output instantaneous over current | Insufficient ramp times Phase to phase or phase to ground short circuit on the drives output Drive requires autotuning to the motor Motor or motor connections changed, re-autotune drive to motor |
| OI.br** | Braking Resistor instantaneous over current | Excessive current in braking resistor Braking resistor value to small |
| O.SPd | Over Speed | Excessive motor speed (typically caused by a mechanical load driving the motor |
| tunE | Autotune stopped before completion | Run command removed before autotune compelte |
| It.br | I2t on Braking Resistor | Excessive braking resistor energy |
| lt.AC | l2t on drive output current | Excessive Mechanical load High impedance phase to phase or phase to ground short circuit at drive output Drive requires re-autotuning to motor |
| O.ht1 | IGBT over heat based on dries thermal model | Over heat software thermal module |
| O.ht2 | Over heat based on drives heatsink | Heatsink temperature exceeds maximum allowable |
| th | Motor thermistor trip | Excessive motor temperature |
| O.Ld1* | User +24v or digital output overload | Excessive load or short circuit on +24v output |
| cL1 | Analogue input 1 current mode, current loss | Input current less than 3mA when 4-20 or 20-4mA modes selected |
| SCL | Serial communication loss time-out | Loss of communication when drive is under remote control |
| EEF | Internal Drive EEPROM trip | Possible loss of parameter values |
| PH | Input phase imbalance or input phase loss | One of the input phases has become disconnected from the drive (applies to 200/400v three phase drives only, not dual rated drives. |
| rS | Failure to measure motors stator resistance | Motor too small for drive Motor cable disconnected during measurement |
| C.Err | SmartStick data error | Bad connection or memory corrupt within SmartStick |
| C.dAt | SmartStick data does not exist | New/empty SmartStick being read |
| C.Acc | SmartStick read/write error fail | Bad connection or faulty SmartStick |
| C.rtg | SmartStick/drive rating change | Already programmed SmartStick read by a drive of a different rating |
| O.cL | Overload on current loop input | Input current exceeds 25mA |
| HFxx trip | Hardware faults | Internal drive hardware fault |
HF01 to HF03
Not used
HF04
Low DC bus at power up- may indicate an AC Input or pre-charge problem
HF05
No internal handshake signal from second processor (DSP) at start up
HF06
Unexpected interrupt
HF07
Watchdog failure
HF08
Interrupt crash (code overrun)
HF09 to HF10
Not used
HF11
Access to the EEPROM failed- tried to read stored parameter data but failed
HF12 to HF19
Not used
HF20
Power stage – code error Tried to read power board and read back erroneous
HF21
Power stage – unrecognized frame size
HF22
Overcurrent detection at power up- possible output short or bridge failure
HF23
DSP software overrun
HF24
Not Used
HF25
DSP Communications failure- communication from main to 2nd processor
HF26
Soft start relay failed to close; or soft start monitor failed; or braking
IGBT short circuit at power up
HF27
Power stage thermistor fault
HF28
Power circuit thermistor 2 or 3 fault Internal fan fault on size 3 only
HF29
Fan failure (current too high – only on drives with a fan) see note below
HF30
Not used
HF31
Internal Cap Bank Fan failure- check for fan rotation/blockage Size 4 and up
HF32
Power circuit temperature feedback multiplexer failure
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Trip codes can be puzzling, but MRO Electric has the solution. Whether you need in-depth guides to understand your Commander SK drive’s codes or require immediate repair service, we’re here to support you in restoring your system’s efficiency swiftly.
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