VFD

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hawkeye23

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I am helping out on with a alarm on a vfd that comes up as a high temp when there is not a high temp condition. The unit has been off for days. Anyone have an idea why the unit would have a temperature condition. Its a eaton svx 9000 . The alarm is cleared and than power is off for a long period and after power is return with vfd not running it goes into high temp. after about 2 minutes [ on keypad ]
Thanks to all for your time .
 
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hawkeye23 said:
I am helping out on with a alarm on a vfd that comes up as a high temp when there is not a high temp condition. The unit has been off for days. Anyone have an idea why the unit would have a temperature condition. Its a eaton svx 9000 . The alarm is cleared and than power is off for a long period and after power is return with vfd not running it goes into high temp. after about 2 minutes [ on keypad ]
Thanks to all for your time .
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High Temp in a VFD usually means a high temperature on the heat sinks, more specifically a hot spot approaching the point of causing damage to the transistors. Transistors create heat, the heat has to move AWAY from them into the heat sink via conduction, then air flowing over the heat sink moves it out via convection. How are you determining that "there is not a high temp condition"? Just because the ambient temperature is not high does not mean there isn't a problem inside of the VFD. A common one is a fan that is not working or is not at full capacity, i.e. the fan bearings are failing. Vacon, who make that drive for Eaton, have a reputation for having fan problems. they turn the fan on and off with an internal relay and if that relay fails, the fans don't come on. You can actually read the heat sink temperature on the display by going to the Monitoring menu and looking at V7.9. 40C is the danger point.
 
My thought is look at the temperature measuring component. Could be a TC or Thermistor.
Having said that and rereading the OP look for a high temp switch that has failed since you are
still receiving an analog signal or a setpoint set to low. The second would be quick and easy.
If that is good...break an I/O diagram and start troubleshooting. Best luck. :thumbsup:


hawkeye23 said:
Keypad shows 30c which is ok compared to our other vfd that runs at 50c. These vfds operate at well over 50c.
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Jraef said:
High Temp in a VFD usually means a high temperature on the heat sinks, more specifically a hot spot approaching the point of causing damage to the transistors. Transistors create heat, the heat has to move AWAY from them into the heat sink via conduction, then air flowing over the heat sink moves it out via convection. How are you determining that "there is not a high temp condition"? Just because the ambient temperature is not high does not mean there isn't a problem inside of the VFD. A common one is a fan that is not working or is not at full capacity, i.e. the fan bearings are failing. Vacon, who make that drive for Eaton, have a reputation for having fan problems. they turn the fan on and off with an internal relay and if that relay fails, the fans don't come on. You can actually read the heat sink temperature on the display by going to the Monitoring menu and looking at V7.9. 40C is the danger point.
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You may wish to review that.
From the op:

and after power is return with vfd not running it goes into high temp.
Click to expand...
 
Looking at the SVX quick start (I don't have the full manual handy) there are multiple temperature faults. Knowing which fault is active could go a ways in determining the cause. FWIW I had an older SV9000 drive in one of our facilities just north of you last summer that was tripping on over temp as well. It was located in an "electrical room" :cool: with about three dozen other drives. With the driven not running it was just a couple degrees below the trip point at all times due to the heat produced by the other drives.
Capture.JPG
 
Besoeker said:
You may wish to review that.
From the op:
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After about 2 minutes.
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That's why I was suspecting something wrong, because the fault happens after 2 minutes of run time from a cool start. That indicates that the heat is not getting away from the temperature sensor fast enough during that time, which usually points to loss of convection cooling, because the 2 minutes is likely just representing the conductive cooling time constant of the plain heat sink material itself, ie not enough air flow across it.

But the possibility of a bad temperature sensor is another good one, and of course the more in-depth meaning of "high temp" would help to pinpoint where to start looking.
 
"Not running" could mean several things. Clearly it is not powering the motor, and just as clearly the VFD itself is getting power and providing status information while waiting to be asked to power the motor.
I would not expect load on the FETs, but the power to the controller board would be on and there would be voltage on the DC bus.
We still need to know where the indicated temperature is.

Tapatalk!
 
GoldDigger said:
"Not running" could mean several things. Clearly it is not powering the motor, and just as clearly the VFD itself is getting power and providing status information while waiting to be asked to power the motor.
I would not expect load on the FETs, but the power to the controller board would be on and there would be voltage on the DC bus.
We still need to know where the indicated temperature is.

Tapatalk!
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Normally IGBTs rather than FETs
But yes, what overtemp is being indicated.
And you really wouldn't expect any with no power being transferred.
 
VFD up and running so far today ... Found cooling set on temperature on keypad I was told to change to continuous setting to where fan is always running. Cleaned unit inside and out , turned unit back on and it stayed on this time. Can't explain it but glad its working.
Thanks to all you guys for the great help you gave me.
 
I am trying to understand your post, did you find a programmed command to turn cooling on based
on temperature? And Engineering told you to change it to have the fan on all the time; is that correct?
Did this VFD over temp alarm condition just start happening?

hawkeye23 said:
VFD up and running so far today ... Found cooling set on temperature on keypad I was told to change to continuous setting to where fan is always running. Cleaned unit inside and out , turned unit back on and it stayed on this time. Can't explain it but glad its working.
Thanks to all you guys for the great help you gave me.
Click to expand...
 
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Jraef said:
D'oh! :slaphead: I get it now...

Damn, I was being exceptionally thick there... I was inserting words that were not there, essentially assuming the motor was re-started after that long period of being off.

Facts not in evidence... Durrrr...
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We've all been there.
 
I was told to go into the keypad in "hardware" to find how the fans were controlled, the setting was @" temperture " , we changed it to continuos where cooling fans are on all the time. We then took the time and cleaned the vfd and all the controls completely. It worked from that time on.

The vfd sat for days before being needed as a backup.
The problem started days ago when there was a high temperature condition on the keypad. We cleared it and recycled power to vfd . Fans ran for about 30seconds and stop running ,after about 1 or 2 minutes it went into a high temp condition again . VFD had power but would not drive the motor at anytime. At anytime power was applied to vfd fan would run for about 30seconds and then go into a high temp a short time later. I believe the fault codes cam as a 14 and a 32.

Again I like to say thank you guys for your giving us guidance here .
 
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hawkeye23 said:
I was told to go into the keypad in "hardware" to find how the fans were controlled, the setting was @" temperture " , we changed it to continuos where cooling fans are on all the time. We then took the time and cleaned the vfd and all the controls completely. It worked from that time on.

The vfd sat for days before being needed as a backup.
The problem started days ago when there was a high temperature condition on the keypad. We cleared it and recycled power to vfd . Fans ran for about 30seconds and stop running ,after about 1 or 2 minutes it went into a high temp condition again . VFD had power but would not drive the motor at anytime. At anytime power was applied to vfd fan would run for about 30seconds and then go into a high temp a short time later. I believe the fault codes cam as a 14 and a 32.

Again I like to say thank you guys for your giving us guidance here .
Click to expand...

Was there output at this time or was the drive basically idle?
 
Makes more sense now.

That drive allows you to program the actions of the heat sink cooling fans independently of the status of the drive. The default is that the fans only turn on after the drive is running and the heat sink thermal sensor detects it is above 30C. The down side of that strategy is that if you are in an ambient where the temperature is already at 30C (86F) but not running the motor, the fans don't come on but the heat sensor is tripped. The same can happen if running the drive in a mode that heats it up quickly, then you shut it down too soon. The heat rejected by the transistors is still spreading out conductively in the heat sinks, but you have turned off the fan, so it builds up and does not get dissipated convectively. That explains why it tripped after having been off, as in not running, but powered up. The fans would not be on, but it took a couple of minutes for the heat sink sensor to detect the 30C condition of the heat sinks.

So by changing the fan operation to continuous, the fans will be running whenever there is power to the drive, regardless of the Run status.
 
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