VSD trips on over-temperature
The drive trips on over-temperature — usually after running a while, in hot conditions, or under heavy load, because it can't shed heat fast enough.
Safety first
The drive and heatsink can be hot. Allow cooling and prove dead before working. Don't run a drive with cooling defeated.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
Blocked / failed cooling fan
Most likelyA clogged or failed drive cooling fan lets the heatsink temperature climb until it trips.
- 2
Dust-clogged heatsink / filters
#2Dust on the heatsink or blocked enclosure filters stops heat dissipating.
- 3
High ambient / poor enclosure ventilation
#3A hot, sealed, or poorly ventilated enclosure pushes the drive over its limit.
- 4
Overloaded / oversized duty
#4Running near or above rating, or frequent heavy starts, generates more heat than the drive can shed.
- 5
Faulty temperature sensor
Least likelyA failed internal temperature sensor can trip with a genuinely cool drive.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Check the drive cooling fan runs and the heatsink/filters are clean.
Fan running, heatsink and filters clear.
Cooling hardware fine — check ambient and loading.
Failed fan or blocked heatsink/filters — clean/replace.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
VSD over-temperature
→ step 2 - 2decision
Is the cooling fan running and heatsink/filters clean?
Yes→ step 3No→ step 4 - 3decision
Is enclosure ventilation and ambient reasonable?
Yes→ step 5No→ step 6 - 4result
Failed fan / blocked heatsink — clean or replace.
- 5decision
Is the drive operating within rating/duty?
Yes→ step 7No→ step 8 - 6result
Improve enclosure ventilation.
- 7result
Suspect a faulty temperature sensor — refer to documentation.
- 8result
Over-duty — reduce loading or right-size the drive.
Common mistakes apprentices make
- Resetting the over-temp trip without cleaning the fan/heatsink.
- Mounting the drive in a sealed box with no ventilation.
- Running the drive continuously near its limit.
- Not considering a failed temperature sensor.
When to stop & escalate
Persistent over-temperature within rating and with good cooling suggests a sensor or internal fault — refer to the drive support. Under-ventilated installations should be reviewed at design level.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
VSD trips on overcurrent / overload
The drive trips with an overcurrent or overload code — on start, on acceleration, or under running load. It may restart and trip again on the same point in the cycle.
Motor running hot / overheating
The motor runs but gets excessively hot — too hot to touch, smell of hot insulation, or thermal protection cutting in after a while.
VSD powered up but won't start the motor
The drive is energised and the display is alive, but it won't run the motor. No fault may be shown — it just sits in 'ready' or 'stopped' and ignores the start command.