What the Er.201 alarm means

The drive power-stage hardware detected a current spike beyond the IGBT protection threshold and cut output immediately. This is a routine repair in our workshop for INOVANCE IRCB500 / IRCB501 + SV660 servo systems, and we normally pin it down during the first site check.

Most common causes

  • Motor cable U/V/W shorted to ground or phase-to-phase
  • Motor winding insulation failure
  • Damaged IGBT module
  • Coolant or oil inside a motor connector
Field note: Begin with the first item in the list; it has a far higher on-machine occurrence rate than the others.

Step-by-step field fix

  1. Power off, discharge the DC bus, then megger motor phases to ground
  2. Disconnect the motor and power the drive alone — recurring Er.201 means a dead power stage
  3. Open and dry contaminated connectors
  4. Inspect the cable for pinch damage along the robot dress pack
  5. Replace the failed component and re-test at low speed
Safety first: For INOVANCE er-201, this alarm family involves the DC bus, which sits at several hundred volts and stays charged for minutes after power-off - touching terminals is a shock hazard. On site you may not carry out the first step yourself: Power off, discharge the DC bus, then megger motor phases to ground. Beyond that it is the DC bus and power stage work - leave it to a professional. On INOVANCE er-201: checking incoming voltage at the disconnect and looking at breakers and fuses is fine to do yourself; opening the cabinet to touch bus terminals or pulling power modules needs a qualified electrician.

How we diagnose drive alarms on site

INOVANCE er-201 belongs to the drive & power stage family. On INOVANCE er-201 the failing stage is Inovance servos (SV660N class), same family as the robot controller on the Inovance robot controllers (IRCB series and kin) - the fault sits on the energy chain: mains input, rectification, DC bus, braking resistor, inverter power devices and the drive board. We start reading INOVANCE er-201 at the pendant alarm screen (ER.xxx / 0x9xxx segments) and the servo panel Er code.

The chain involved in INOVANCE er-201 runs: three-phase mains -> rectifier -> DC bus (bus capacitors) -> brake chopper / braking resistor -> inverter (IGBT) -> motor.

Motor cable U/V/W shorted to ground or phase-to-phase is common on INOVANCE er-201, but look at the duty cycle: Cells with high-inertia loads or frequent start-stop cycles return far more regenerative energy than a plain transfer cell, and the braking resistor lives in a hot cycle that shortens its life. When we suspect this family we ask what changed: if the takt was raised recently or a heavier fixture went on, the alarm cluster usually lines up with that process change. Replacing the resistor alone will not fix it - the chopper rating and resistor wattage have to be re-checked against the new duty.

Field notes on this page cover INOVANCE er-201 (Hardware Overcurrent); written by the Henghuan repair team, updated 2026-10-01.

If you can't fix it, reach our engineers directly

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Related Drive & Power Stage alarms

Er.210 — Motor Overload Er.400 — Main Circuit Overvoltage Er.410 — Main Circuit Undervoltage Er.610 — Drive Overload (I2t) Er.920 — Regenerative Overload
Same family: this code belongs to the Drive & power stage alarms family - the page collects all Drive & power stage-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for EFORT · JAKA · AUBO and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the INOVANCE er-201 alarm mean?

The drive power-stage hardware detected a current spike beyond the IGBT protection threshold and cut output immediately. This is a routine repair in our workshop for INOVANCE IRCB500 / IRCB501 + SV660 servo systems, and we normally pin it down during the first site check. INOVANCE er-201 sits in the drive & power stage family; on our work orders the highest-frequency trigger for this code is "Motor cable U/V/W shorted to ground or phase-to-phase".

QCan I clear a INOVANCE er-201 alarm myself?

Whether INOVANCE er-201 clears on its own depends on the outcome of "Power off, discharge the DC bus, then megger motor phases to ground". Finish the flow with "Replace the failed component and re-test at low speed" to confirm INOVANCE er-201 - do not skip it. If that step is clean, the second most frequent cause on INOVANCE er-201 is "Motor winding insulation failure". Do not chase takt through a repeating INOVANCE er-201. Left alone, drive & power stage faults tend to graduate from repairable to must-replace.

QFor drive/power alarms like INOVANCE er-201, what spares do you bring on site?

The commonest causes we see on INOVANCE er-201 are "Motor cable U/V/W shorted to ground or phase-to-phase, Motor winding insulation failure, Damaged IGBT module", so we stock the van against those. For INOVANCE er-201 specifically, we stock the van along the energy chain: braking resistors, bus capacitors, input fuses, drive-board supply parts and the common power modules for the brand. For INOVANCE er-201, drive alarms usually stop the whole line, so they sit at the front of our dispatch queue. Before we roll, tell us what INOVANCE er-201 shows on the pendant alarm screen (ER.xxx / 0x9xxx segments) and the servo panel Er code and what the machine was doing - phone or video triage is free.

The notes on INOVANCE er-201 were summarized by the Henghuan Robotics repair team from on-site service. The alarm interpretation is our empirical summary for troubleshooting reference and may vary by controller and software version — please check INOVANCE documentation or contact us with questions. Henghuan is an independent service provider, not affiliated with or endorsed by INOVANCE.