WEG CFW500 fault F0022: Overvoltage on the DC link
The DC link voltage (P0004) rose above the maximum for the supply set in P0296, and the inverter tripped. WEG’s trip levels are 410 Vdc for 200–240 Vac supplies, 810 Vdc for 380–480 Vac and 1000 Vdc for 500–600 Vac.
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When it happens
- During deceleration, especially of high-inertia loads
- With loads that drive the motor at constant speed (eccentric loads, sucker-rod pumps, cranes)
- At any time if the supply voltage is too high
Likely causes and checks
1Load inertia too high or deceleration ramp too fast
- Points to it
- Trips only on stops or speed reductions.
- Check
- Check the deceleration time P0101 and the load inertia; check that DC link regulation is set (P0150/P0151 in V/f and VVW, P0184/P0185 in vector control).
2P0151, P0153 or P0185 set too high
- Points to it
- Trips on deceleration even with DC link regulation or a braking resistor fitted.
- Check
- Check the regulation level (P0151 or P0185) and the braking level P0153 against the factory values for the supply.
3Supply voltage too high
- Points to it
- Trips even on gentle stops or at standstill.
- Check
- Measure the supply voltage and compare it with the inverter label.
4Wrong supply voltage or P0296 setting
- Points to it
- Trips after installation or a change of supply.
- Check
- Check that the inverter label and P0296 match the actual supply.
Telling it apart
- Trips during deceleration point to regenerated energy (ramp, DC link regulation, braking); trips while running steadily or stopped point to the supply.
- WEG notes that when rheostatic braking is used, the DC link regulation functions (Ramp Hold or Accelerate Ramp) must be disabled; with a braking resistor fitted, check P0153 and the resistor rather than the regulator.
- If P0153 is set close to the F0022 level, the overvoltage can trip before the braking resistor dissipates the energy.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| P0101 | Deceleration time | Too short a ramp is a listed cause; a longer ramp returns energy more slowly. |
| P0150 | Type of DC link regulator (V/f, VVW) | Ramp Hold (0 or 2) or Accelerate Ramp (1 or 3) to contain the DC link voltage. |
| P0151 | DC link regulation level (V/f, VVW) | Voltage at which DC link regulation acts; set too high is a listed cause. |
| P0184 / P0185 | DC link regulation mode and level (vector) | Extends the deceleration ramp automatically to keep the DC link below P0185. |
| P0153 | Rheostatic braking level | Voltage at which the braking IGBT switches in; must suit the supply. |
| P0296 | Line rated voltage | Must match the actual supply. |
Evidence to collect
- Fault history P0050–P0055, especially P0052 (DC link) and P0053 (frequency) at the trip
- Deceleration time P0101
- Settings of P0150, P0151, P0184, P0185 and P0153
- Whether a braking resistor is fitted and its condition
- Measured supply voltage and P0296
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