WEG CFW500 fault F0072: Motor overload
The inverter’s motor overload function (Ixt) estimates winding heating by integrating output current above the overload current set in P0156–P0158. At a constant 150 % of that current it trips in 60 seconds; above 150 % it trips sooner. P0037 shows the overload level; F0072 trips when it reaches 100 %, and alarm A0046 warns earlier, at the level set in P0349.
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Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your WEG CFW500. InduQT compares the evidence and suggests the next useful checks.
When it happens
- During sustained running above the motor’s overload current
- With a heavy or jammed load on the motor shaft
- After a restart, because the Ixt value is kept in non-volatile memory
Likely causes and checks
1P0156, P0157 or P0158 set too low for the motor operating current
- Points to it
- Trips after commissioning or a motor change, with the motor running at normal load.
- Check
- Compare P0156–P0158 with the motor rating plate; WEG recommends P0156 about 10 % above the motor rated current P0401.
2Overload on the motor shaft
- Points to it
- Motor current is high in P0003 and P0037 climbs steadily; alarm A0046 shows before the trip.
- Check
- Check the driven machine for overload, binding or a process change.
Telling it apart
- F0072 protects the motor and depends on P0156–P0158; F0048 is the separate overload protection of the inverter’s IGBTs.
- The overload current depends on speed: P0158 applies below 5 % of rated speed, P0157 from 5 % to 50 %, and P0156 above 50 %. Trips at low speed point to the P0157/P0158 settings and the load at low speed.
- Because the Ixt value survives a power cycle, a motor that tripped on F0072 may trip again soon after a restart if it has not cooled.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| P0156 | Overload current at rated speed | WEG recommends about 10 % above the motor rated current (P0401). |
| P0157 | Overload current at 50 % of rated speed | Applies between 5 % and 50 % of rated speed. |
| P0158 | Overload current at 5 % of rated speed | Applies below 5 % of rated speed. |
| P0037 | Motor overload Ixt | Present overload level; F0072 trips at 100 %. |
| P0349 | Level for alarm Ixt | Level at which alarm A0046 warns; 100 % disables the alarm. |
| P0401 | Motor rated current | Reference for setting P0156. |
Evidence to collect
- Fault history P0050–P0055, especially P0051 (current) and P0053 (frequency) at the trip
- P0037 trend before the trip and any A0046 alarms
- Settings of P0156, P0157, P0158 and P0401 against the motor rating plate
- Load on the motor shaft and the duty cycle
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