Fried my VFD. What did I do wrong??

whattheheld · May 18, 2017

Hi all,

I have a VFD I was moving from running a vent to running a more essential conveyer that had had the VFD go out on it yesterday. The Original VFD had all the same nameplate info as the one I was trying to swap in, the only difference being the one I was trying to swap in required 240V and not 120V single phase.

Keep in mind these VFD's are in the same circuit on a 50A breaker. So in order to swap the 240V VFD into the place of the 120V VFD I had toconnect one 120V leg of a safety switch and another 120V leg of the safety switch to L1 and L2 on the VFD. The neutral in the safety switch was left untouched. I also connected ground to the safety switch. The safety switch has 15 amp fuses in it.

When I turned on power the VFD sparked, showed a Low voltage message and then died. Any ideas on what I did wrong? I keep going over everything in my head and I can't figure it out. Thanks in advance.

The 240V VFD is a GS1-20P5 Automation Direct Unit. The old 120V unit is a VFD004S11B Delta Electronics Unit.

-Conner

rons · May 19, 2017

whattheheld said:
So in order to swap the 240V VFD into the place of the 120V VFD I had to connect one 120V leg of a safety switch and another 120V leg of the safety switch to L1 and L2 on the VFD.

Where the two phases (legs) 180 degrees out of phase?

Jraef · May 19, 2017

whattheheld said:
... I also connected ground to the safety switch. ...

Explain what you mean by that.

Also, was the 230V VFD new or used?

Monarchist · May 19, 2017

rons said:
Where the two phases (legs) 180 degrees out of phase?

USA. Single-phase/split-phase? I think I grok what and why on the question, but..

If not, they'd be zero diff leg-to-leg but still 120 VAC above PE/Neutral. Unless.. he is trying to pull 1-P off a high-leg delta 3-P supply?

In any case... two VFD. Not even the same tribe, and the prior one was a voltage doubler, new one is NOT?

Go strictly - I say again STRICTLY - 'by the book' for the NEW VFD.

JST · May 20, 2017

Describe EXACTLY what you connected, and maybe it can be determined what went wrong.

I assume the spark was INSIDE the VFD?

That model is for single or 3 phase input, 230V, so nominally it should have worked for your application. But, it is possible to foul up the install.

One common problem is to connect motor to line terminals, and line to motor terminals. That often will pop a diode in the output section, and may cause a visible spark inside. The display may come on, and then die.

moonlight machine · May 20, 2017

whattheheld said:
Hi all,

I have a VFD I was moving from running a vent to running a more essential conveyer that had had the VFD go out on it yesterday. The Original VFD had all the same nameplate info as the one I was trying to swap in, the only difference being the one I was trying to swap in required 240V and not 120V single phase.

Keep in mind these VFD's are in the same circuit on a 50A breaker. So in order to swap the 240V VFD into the place of the 120V VFD I had toconnect one 120V leg of a safety switch and another 120V leg of the safety switch to L1 and L2 on the VFD. The neutral in the safety switch was left untouched. I also connected ground to the safety switch. The safety switch has 15 amp fuses in it.

When I turned on power the VFD sparked, showed a Low voltage message and then died. Any ideas on what I did wrong? I keep going over everything in my head and I can't figure it out. Thanks in advance.

The 240V VFD is a GS1-20P5 Automation Direct Unit. The old 120V unit is a VFD004S11B Delta Electronics Unit.

-Conner

What did I do wrong????? You did not call someone who knows what they are doing, maybe an electrician perhaps.

whattheheld · May 20, 2017

To shed some light on the situation before I begin to attempt to reply to everyone: I was actually mistaken. There are 3 lines coming into the safety switch and each one is 120 to ground. The left wire is on its own breaker( Edit: its connected to a 10A breaker, which is downstream of the 50A breaker...) and the middle and right wire were on their own breaker. I had measured 240V between left and right wire so those were the two wires I had used to hook up to the VFD. Looking back I realize that was most likely my issue.

rons said:
Where the two phases (legs) 180 degrees out of phase?

Would I check this by testing each phase to ground and one should show a negative voltage and one a positive voltage?

Jraef said:
Explain what you mean by that.

Also, was the 230V VFD new or used?

I connected the ground of the input terminal on the VFD to ground on the safety switch.

The 230V VFD was currently being used for another application before I removed it to install here.

Monarchist said:
USA. Single-phase/split-phase? I think I grok what and why on the question, but..

If not, they'd be zero diff leg-to-leg but still 120 VAC above PE/Neutral. Unless.. he is trying to pull 1-P off a high-leg delta 3-P supply?

In any case... two VFD. Not even the same tribe, and the prior one was a voltage doubler, new one is NOT?

Go strictly - I say again STRICTLY - 'by the book' for the NEW VFD.

I tried to go by the book as possible for this VFD. All specs were the same except for the input voltage. As long as output voltage was the same I didn't see an issue?

JST said:
Describe EXACTLY what you connected, and maybe it can be determined what went wrong.

I assume the spark was INSIDE the VFD?

That model is for single or 3 phase input, 230V, so nominally it should have worked for your application. But, it is possible to foul up the install.

One common problem is to connect motor to line terminals, and line to motor terminals. That often will pop a diode in the output section, and may cause a visible spark inside. The display may come on, and then die.

Left wire of safety switch (120V to ground) was connected to L1 of VFD. Right wire of safety switch was connected to L2 of VFD. Ground was connected to ground terminal on Input side of VFD and to a screw on the safety switch that was already being used as a ground. The situation went exactly as you describe except I did not install mix up line and motor terminals. I have installed these VFD's in the past and the motor and line wires look very different.

Thanks for your help everyone. I've already fixed the issue with a new VFD with 120V input. I still am curious as to what happened however. Any explanation would be appreciated

whattheheld · May 20, 2017

moonlight machine said:
What did I do wrong????? You did not call someone who knows what they are doing, maybe an electrician perhaps.

How about you keep your unhelpful posts to yourself????? Thanks. I'm not a pro, but I know how to safely work around electricity and know when to call an electrician. I've burnt out one VFD which would cost $117 new, which it isn't new.

cyanidekid · May 20, 2017

moonlight machine said:
What did I do wrong????? You did not call someone who knows what they are doing, maybe an electrician perhaps.

ok everybody, let's ease up on the OP, and first of all, before ragging on him, lets at least read #1.

he said it was installed and running a "vent".

what was the output rating on the VFD units?

is it possible the starting current on the conveyor was much higher than the vent?

did the same two legs power it? if the same legs went to the same unit, it's highly unlikely to be the supply..

what was the problem that fried the VFD that was running the conveyor? if that wasn't found and corrected, I.E., fault was not inside the VFD, the same thing that fried the original, fried the swapped in unit.

are the vent motor and the conveyor motors the same input rating? if they are re-configureable multi-voltage units, (120-240), are they actually in the same voltage config?

forgive items answered in #7, was typing..

whattheheld · May 20, 2017

cyanidekid said:
ok everybody, let's ease up on the OP, and first of all, before ragging on him, lets at least read #1.

he said it was installed and running a "vent".

what was the output rating on the VFD units?

is it possible the starting current on the conveyor was much higher than the vent?

did the same two legs power it? if the same legs went to the same unit, it's highly unlikely to be the supply..

what was the problem that fried the VFD that was running the conveyor? if that wasn't found and corrected, I.E., fault was not inside the VFD, the same thing that fried the original, fried the swapped in unit.

are the vent motor and the conveyor motors the same input rating? if they are re-configureable multi-voltage units, (120-240), are they actually in the same voltage config?

forgive items answered in #7, was typing..

Sorry to be confusing, i was trying to avoid explaining every detail. But it was connected to a motor which opens and closes a vent.

The output rating was the same for both VFD's. I attached both models in the original post if anyone want more information. It is very possible the starting current was higher.

I thought the same two legs did power it since when i flipped that 50A breaker off everything inside the safety switch died as well as the vfd running the vent.

The problem with the vfd running the conveyer was an internal hardware issue according to the code it was displaying. It was an old unit.

I dont know if they were the same voltage, (checking the nameplate of the vent motor would be a huge pain in the ass). I thought i would have time once i hooked it up to reprogram everything though. (In hindsight i probably should have reprogrammed it before moving it) It didnt look like it attempted to run the conveyer motor before it sparked and turned off though.

JST · May 20, 2017

Aside from a possible fault in the replacement....

1) The voltages TO GROUND were not what you thought, and the spark was an overvoltage protector in the unit frying?

2) The voltage supplied was too low to run the unit properly, but high enough for it to work somewhat. The inrush protection in the VFD got fried due to not being cut out of circuit since the voltage was low (many are not cut out until voltage reaches a certain level). This assumes the VFD started up when power was applied, since normally the inrush protection can run the control circuit just fine.

Those are quite possible, and #2 would explain a lot of it.

JST · May 20, 2017

Let's lighten up here.....

Having an electrician do the work can be a good idea. I don't consider the comments made above to be entirely appropriate. There is one point that might be underappreciated here, however, see below.

The OP appears to have checked things and done what would normally be appropriate, and to understand the basics of dealing with VFDs. The VFD appears from its manual, to be appropriate for the voltage the OP reports was present. It is unlikely from the explanation that the voltage was too high.

Whatever the problem really was, I find it unlikely, given my experience of plain "electricians", that just being an electrician would have avoided the problem of damaging the VFD. Being an experienced industrial electrician might definitely have helped. Being the electrician who wired up the installation would have been best, as it seems to be a little confusing.

The one issue that I see is the choice of wires.

One wire seems to have been from a 10A breaker, the other from an unrelated breaker. This is not proper.

Both the wires to a VFD ought to be on a single double pole breaker (for US 240V) that is "tied", that is, a fault on either one will open both. That is not how this was wired, as I understand it. Now, that would NOT cause (by itself) the VFD to be fried. But it is contrary to code and general good practice.

Then also, for single phase, the specified breaker is 25A. The OP had one 10A, and one I don't think was specified. The 10A would have been right for 3 phase input to the GS1-20P5, but was not correct for the single phase unit.

HAS the VFD been confirmed to be dead? I expect so, but I don't know if it was actually said. If the 10A breaker opened due to inrush current, the same sort of result, of the VFD quitting and reporting low volts, would have occurred. I should have made that item 3 on my list.

Most any "electrician" would have avoided that type wiring issue, more-or-less by reflex. That cannot be denied.

rons · May 21, 2017

whattheheld said:
Would I check this by testing each phase to ground and one should show a negative voltage and one a positive voltage?

No, not unless you could stop time. If all you have is a multi-meter then a AC voltage reading from phase 1 to phase 2 is going to read as 220-240v.

What I always do before moving a VFD from one installation to another is check/change all the programming parameters first before connecting the new motor.

cyanidekid · May 21, 2017

just one more note, the OP went by the error code displayed by the VFD, (showing an internal fault, and was lucky it was right, or he might have fried the 3rd one, if I read correctly.)

the error codes displayed on a VFD should be considered a good starting point to diagnose the problem, they are useful, but far from infallible.

before risking a replacement in a swap out, test to confirm all parameters are looking ok, such as correct input voltage, motor wired for proper voltage, control curcit(s) showing proper voltage, unit programmed properly, etc..as long as you have the time..I.E., no zombies headed for the doors..! (yes, they have internal protection provisions, but also not infallible.) just good practice..cheers and work safe.

whattheheld · May 22, 2017

JST said:
Aside from a possible fault in the replacement....

1) The voltages TO GROUND were not what you thought, and the spark was an overvoltage protector in the unit frying?

2) The voltage supplied was too low to run the unit properly, but high enough for it to work somewhat. The inrush protection in the VFD got fried due to not being cut out of circuit since the voltage was low (many are not cut out until voltage reaches a certain level). This assumes the VFD started up when power was applied, since normally the inrush protection can run the control circuit just fine.

Those are quite possible, and #2 would explain a lot of it.

I still am doubtful of #1 being the issue, but #2 is possible. If it helps the 10A breaker on one line tripped when the VFD sparked and turned off.

JST said:
Let's lighten up here.....

Having an electrician do the work can be a good idea. I don't consider the comments made above to be entirely appropriate. There is one point that might be underappreciated here, however, see below.

The OP appears to have checked things and done what would normally be appropriate, and to understand the basics of dealing with VFDs. The VFD appears from its manual, to be appropriate for the voltage the OP reports was present. It is unlikely from the explanation that the voltage was too high.

Whatever the problem really was, I find it unlikely, given my experience of plain "electricians", that just being an electrician would have avoided the problem of damaging the VFD. Being an experienced industrial electrician might definitely have helped. Being the electrician who wired up the installation would have been best, as it seems to be a little confusing.

The one issue that I see is the choice of wires.

One wire seems to have been from a 10A breaker, the other from an unrelated breaker. This is not proper.

Both the wires to a VFD ought to be on a single double pole breaker (for US 240V) that is "tied", that is, a fault on either one will open both. That is not how this was wired, as I understand it. Now, that would NOT cause (by itself) the VFD to be fried. But it is contrary to code and general good practice.

Then also, for single phase, the specified breaker is 25A. The OP had one 10A, and one I don't think was specified. The 10A would have been right for 3 phase input to the GS1-20P5, but was not correct for the single phase unit.

HAS the VFD been confirmed to be dead? I expect so, but I don't know if it was actually said. If the 10A breaker opened due to inrush current, the same sort of result, of the VFD quitting and reporting low volts, would have occurred. I should have made that item 3 on my list.

Most any "electrician" would have avoided that type wiring issue, more-or-less by reflex. That cannot be denied.

I do completely agree with the breakers. I was confused and am still confused as to why everything is wired the way it is. I ordered a replacement VFD with the exact same parameters as the first and just directly swapped it in. I haven't had any issues since.

I have no confirmed it dead, I haven't had the chance to reinstall it to its original location. Sparks and burning plastic smells don't bode well though.

I don't deny that having an electrician do it would have most likely gone better. I did everything I needed to ensure I was safe while I was working with the electricity and had the electricity shut off within 5 seconds of an issue being noticed. I at most lost $117(less than that really because the VFD wasn't new). I seriously doubt calling an electrician out would have been anywhere close to that. Looking at the cost effectiveness and the risk, I do not regret my decision. Next time I will go through the entire system and know 100% how it is wired before I attempt anything like this again.

cyanidekid said:
just one more note, the OP went by the error code displayed by the VFD, (showing an internal fault, and was lucky it was right, or he might have fried the 3rd one, if I read correctly.)

the error codes displayed on a VFD should be considered a good starting point to diagnose the problem, they are useful, but far from infallible.

before risking a replacement in a swap out, test to confirm all parameters are looking ok, such as correct input voltage, motor wired for proper voltage, control curcit(s) showing proper voltage, unit programmed properly, etc..as long as you have the time..I.E., no zombies headed for the doors..! (yes, they have internal protection provisions, but also not infallible.) just good practice..cheers and work safe.

Good point. I didn't think to double check the error codes. Those are fantastic suggestions and I will put them in practice in the future.

Thanks for your help everyone. Like I said earlier I just wanted to find out what happened. I had the new replacement VFD installed and functioning 2 days after the original went out. The only thing I lost in this was a 5 year old VFD and ended up learning a lot from all of you which I chalk up to a pretty good trade.

Jraef · May 22, 2017

You said that other VFD (the one that fried) had been used on something else before, but how long before? It makes a difference. If whatever it was had been idle and not powered for a year or more, you may have damaged it because the capacitors inside of the drive needed to be "re-formed" before being energized the first time.

JST · May 22, 2017

If a similar unit connected the same way worked, it is probable that it is something about that unit.

Internal fault? Something conductive that got in it and caused a short? Needing to form the capacitors?

All possible problems. No idea which.

Sparks suggest a piece of something got in and shorted. I have seen folks switch on units after well over a year and be fine, so that's not a guarantee of trouble.

Jraef · May 22, 2017

No, not a guarantee for sure, just a possibility. And the way he worded it, could have been 5 years. I just had a customer blow up 3 brand new drives in a row after pulling them out of their Spares inventory, where they have been sitting unopened for 3 years. They didn't think to call anyone until after the 3rd one fried...

rons · May 22, 2017

Jraef said:
I just had a customer blow up 3 brand new drives in a row after pulling them out of their Spares inventory, where they have been sitting unopened for 3 years. They didn't think to call anyone until after the 3rd one fried...

I wouldn't be surprised if those three drives were all they had in stock.

Tony Quiring · May 22, 2017

There are lessons to be learned here.

First is checking any programming and setup followed by taking photos before touching.

Measure voltage on each and every wire relative to every other wire to determine which wire is on what breaker and if 120 or 208 or 3 phase.

Had that been done the swap may have not cooked anything as the determination of compatible voltages could have been done.

We read one was 120 vac and other was 240 vac so these on the surface are not swappable as is but depending on facility wiring a neutral could have been pulled to allow one main from the 240 circuit to be configured as 120 vac.

You may have done that though.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Fried my VFD. What did I do wrong??

Plastic

Diamond

Titanium

Diamond

Diamond

Diamond

Plastic

Plastic

Titanium

Plastic

Diamond

Diamond

Diamond

Titanium

Plastic

Titanium

Diamond

Titanium

Diamond

Titanium

Similar threads