Was troubleshooting an over temp issue on an Eaton SVX9000 VFD today. Fault code was F14 unit over temperature. The drive was cleaned out recently and the fan was working and pulling lots of air through the heat sink. The cabinet that houses the VFD also had 2 fans that were providing good air flow. I believe the high temp alarm is at 75 degrees c and the fault is at 90 degrees c. Any ideas?
Eaton SVX 9000 VFD Overtemp
- Thread starter baylwin
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petersonra
Senior Member
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- Northern illinois
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- engineer
do you have in infrared thermometer? you could see what the heat sink temperature actually is.
you can probably look at the temperature the vfd thinks he heat sink is at and see if they are close.
i will say this. it does not take a lot of dust or dirt to clog up a heat sink, even if the fan is still pulling what appears to be a significant amount of air.
what is the ambient temperature? most older drives don't like it above about 40 deg c.that is only about 100 deg f. what is the temp inside the cabinet when the fault happens?
you can probably look at the temperature the vfd thinks he heat sink is at and see if they are close.
i will say this. it does not take a lot of dust or dirt to clog up a heat sink, even if the fan is still pulling what appears to be a significant amount of air.
what is the ambient temperature? most older drives don't like it above about 40 deg c.that is only about 100 deg f. what is the temp inside the cabinet when the fault happens?
That’s a good idea to try the infrared thermometer and compare the temp to what the display says. Ambient temperature has been around 30-35 degrees c. I wonder if it’s possible that there is a temperature sensor inside the vfd that is failing or if it is actually getting that hot inside it.
Cow
Senior Member
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- Eastern Oregon
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- Electrician
I've changed quite a few drives that were older and started throwing over temp codes for no reason. It seems to be one of the more common failure modes.
petersonra
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- Northern illinois
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- engineer
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- San Francisco Bay Area, CA, USA
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- Electrical Engineer
Vacon (the manufacturer of that drive) uses a PTC thermistor as the heat sink thermal element. A PTC (Positive Temperature Coefficient of resistance) thermistor increases resistance as the temperature increases. So the monitor circuit looks for a steep rise in the resistance to know if it needs to trip. A broken wire or a loose connection (from maybe, say a recent cleaning?) means infinite resistance, which the monitor circuit will assume is a hot heat sink.
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