Yaskawa GA500 troubleshooting
The GA500 is Yaskawa’s industrial AC microdrive and the successor Yaskawa names for the V1000. Codes are short text (oC, ov, Uv1, GF). The same text can be a fault or a minor fault/alarm: when the ALM LED stays lit it is a fault that stopped the drive; when it flashes it is an alarm and the drive keeps running.
Diagnose this with AI
Try Free Drive Diagnostic Upload a photo of the alarm screen, the fault history or a data export. InduQT compares the evidence and suggests the next useful checks.
How it reports faults
- The keypad shows the code; the list in the manual also gives the hex code used over communications (for example oC = 0007, ov = 0008 as a fault).
- U2-xx [Fault Trace] shows the drive state just before the latest fault: U2-03 frequency reference, U2-04 output frequency, U2-05 output current and U2-08 DC bus voltage at the fault.
- U3-xx [Fault History] holds the most recent faults; o4-11 resets both U2 and U3 records.
- Fault trace is not available for Uv1 and Uv2, according to the manual.
- L5-01 sets the number of auto-restart attempts; for GF, oH1, ov and Uv1 the manual notes L5-08 [Fault Reset Enable Select Grp2] controls auto restart.
Fault codes
| Code | Name |
|---|---|
| oC | Overcurrent |
| ov | Overvoltage |
| Uv1 | DC Bus Undervoltage |
| GF | Ground Fault |
| oL1 | Motor Overload |
| oH | Heatsink Overheat |
| boL | Braking Transistor Overload |
| bUS | Option Communication Error |
| CE | Modbus Communication Error |
| CF | Control Fault |
| CoF | Current Offset Fault |
| EF1 | External Fault (Terminal S1) |
| Err | EEPROM Write Error |
| FbL | PID Feedback Loss |
| LF | Output Phase Loss |
| LF2 | Output Current Imbalance |
| oH1 | Heatsink Overheat |
| oH3 | Motor Overheat (PTC Input) |
| oH4 | Motor Overheat Fault (PTC Input) |
| oL2 | Drive Overload |
| oL3 | Overtorque Detection 1 |
| oL4 | Overtorque Detection 2 |
| PF | Input Phase Loss |
| rH | Braking Resistor Overheat |
| rr | Dynamic Braking Transistor Fault |
| SC | Short Circuit/IGBT Failure |
| SEr | Speed Search Retries Exceeded |
| SToF | Safe Torque OFF (alarm) |
| STPo | Motor Step-Out Detected |
| Uv2 | Control Power Undervoltage |
| Uv3 | Soft Charge Answerback Fault |
Evidence to collect
- Keypad photo showing the code and whether the ALM LED is steady or flashing
- U2-xx fault trace values and U3-xx history
- Drive model (o2-04) and software version
- Control method A1-02 and motor data E2-xx (or E5-xx for PM motors)
- C1-01/C1-02 ramps, L3-04 and L3-11 settings, braking option
- What the machine was doing at the trip
Work on fuel trains, burners, pressure vessels and electrical equipment must be done by qualified personnel following the manufacturer’s documentation and local codes. Never bypass a safety device or interlock.