|
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
Joe, the problem is downstream from the drive, probably the motor itself, but possibly other components between drive and motor.
Unbalanced supply voltages will cause unbalanced currents, and this is why the simple test of swapping leads.? If the high current follows the supply lines, it indicates voltage differential on the supply side.? If the unbalanced currents remain the same as you switch supply leads, it demonstrates that the load (motor) is "pulling" different currents.? But if the supply voltages are balanced, only the load can cause current imbalance.
Think of the analogy of electricity to a water supply, where voltage is water pressure (potential force) and current is water flow rate.? Imagine three supply pipes (same diameter).? If the pressure (voltage) is the same on all three supply lines, there is no way the supply can cause differential flow rate (current.)? ?Only the load side can cause flow rate differences, for example just imagine each load being a valve.? ?Opening the valves different amounts will result in different flow rates (current).? ?Or if it helps to think of work being done, imagine each pipe being connected to a turbine, and the three turbines have different degrees of turning resistance.
A motor with damaged windings, damaged insulation, a bent shaft and other things can cause current imbalance.? For example, a bent shaft causes an unequal air gap between the rotor and the stator, which means unequal flux density and current differences.? A very poor (loose, corroded) terminal can increase resistance enough to screw things up.
Inspect for the obvious (loose connections, etc) and if nothing found, take the motor to a motor shop.?
PS, yes unequal phasing will also cause current differential.? But it's almost impossible that the utility is delivering unequal phasing, and your other motors prove that is not the case.?
|
Joe,
I agree with Mark. As I read you post, first thought was to check the output side of the VFD.
You say VFD faults out but it is not clear how long it runs the motor before faulting out. So are the currents you report startup or running? RMS or peak to peak from a scope measurement.
If you are doing a scope measurement, your 20A current is in line with my RL125 with similar size motor (4KW - 5.4HP). Mine shows +/- 22A peak to peak on scope. If this is your scenario, it appears the low current on one leg is the problem not the 2 high legs. Look for an anomaly in that leg/winding.
If the currents you report are RMS running currents, then the 20A legs appear high so I would look at those 2 legs/windings.
FWIW, here is the link to the post where I documented starting and idling currents of various size motors
Hope this helps.
Imran
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Show quoted text
On Jun 4, 2021, at 12:43 AM, Joe Jensen <joe.jensen@...> wrote: ? I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
Have you tried running directly from the utility three phase and checking the amp draw to see if it is uneven?? If that is the case it could be a motor issue.? Dave
toggle quoted message
Show quoted text
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
The current pull is due to the motor, so tracking it down means asking "why would the motor pull current unevenly?".? I would suspect that the motor needs the pole terminals verified?on the terminal block. I have a sneaking suspicion that it's got a configuration error with the motor's terminal block where the poles are oriented to each of the 3 phase lugs. First suspicion is to find that the motor is wired for Wye when it should?be Delta (or vice-versa).? Second thought is that the VFD is programmed for Delta-In and Wye-Out? instead of Delta-IN, Delta-OUT . This might be just a programming issue and easy to toggle by guessing. Third thought one pair of poles are overloaded on one phase?lug. Fourth thought is that one or more poles are wired out-of-sequence on the phase lugs.
Pole wiring configuration issues are harder to identify with the motor up to speed under continuous light loading like a fan motor here but more dramatic and obvious when ramping up from low rpms like the new VFD is attempting to do. That said, pole wiring mistakes are quite rare, my guess is the VFD is trying to power one 3phase setup while the motor is the other.
|
Hi Joe,
More thoughts after rereading your post.
You mention original VFD as single phase and new as 3 phase input. This could be important if you are running with single phase input.
At first I thought you were running new VFD with single phase input but you report 3 input currents. Just curious, why are you using a VFD with 3 phase input on a dust collector with a 3 phase motor?
Another thought. I am sure you know this, on a VFD, the single or 3 phase input is used to create a DC power supply. This to me means that there should not be a repeatable phase relationship between input and output currents. A resolution to your problem can help further our understanding of how these things work.
Imran
toggle quoted message
Show quoted text
On Jun 4, 2021, at 12:43 AM, Joe Jensen <joe.jensen@...> wrote: ? I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
I have not tried running the 5HP directly off 3 phase.? The currents out of the VFD into that motor are nearly identical.? As I understand it from reading
on the issue, the VFD takes power in from 3 legs, converts to DC and then manufactures 3 phases of AC out.? It would not be too difficult to test the motor without the VFD.
?
Also this am I ran the bandsaw again (no VFD) and the current leg B (the one I’m having trouble with) was a little lower than the other two.? A=9.65A,
B=9.30A and C=9.60A.? Leg C is the wild leg.
?
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Show quoted text
From: [email protected] < [email protected]>
On Behalf Of David Kumm
Sent: Friday, June 4, 2021 6:46 AM
To: [email protected]
Subject: Re: [FOG] VFD issue with 3 Phase power supply
?
Have you tried running directly from the utility three phase and checking the amp draw to see if it is uneven?? If that is the case it could be a motor issue.? Dave
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
Interesting and I will dig in.? This motor has been running on a single to 3 phase VFD for 10 years with no issues and the currents out of the 3 phase
VFD are very very close to each other.?
?
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Show quoted text
From: [email protected] < [email protected]>
On Behalf Of Brett Wissel
Sent: Friday, June 4, 2021 7:17 AM
To: [email protected]
Subject: Re: [FOG] VFD issue with 3 Phase power supply
?
The current pull is due to the motor, so tracking it down means asking "why would the motor pull current unevenly?".? I would suspect that the motor needs the pole terminals verified?on the terminal block. I have a sneaking suspicion that
it's got a configuration error with the motor's terminal block where the poles are oriented to each of the 3 phase lugs.
?
First suspicion is to find that the motor is wired for Wye when it should?be Delta (or vice-versa).?
Second thought is that the VFD is programmed for Delta-In and Wye-Out? instead of Delta-IN, Delta-OUT . This might be just a programming issue and easy to toggle by guessing.
Third thought one pair of poles are overloaded on one phase?lug.
Fourth thought is that one or more poles are wired out-of-sequence on the phase lugs.
Pole wiring configuration issues are harder to identify with the motor up to speed under continuous light loading like a fan motor here but more dramatic and obvious when ramping up from low rpms like the new VFD is attempting to do. That
said, pole wiring mistakes are quite rare, my guess is the VFD is trying to power one 3phase setup while the motor is the other.
|
Some more background.? I brought the idea of variable speed to increase suction on small ports to Robert founder of Oneida at the Vegas show like 10
years ago.? We traded a ton of emails and he swore me to secrecy and the idea became the Oneida Smart collector which won innovation of the year at either Vegas or Atlanta.? In appreciation for the idea Oneida upgraded my collector to a 5HP Smart collector,
single phase input.
?
Lately I was having some issues with the 10 year old VFD shutting down and Oneida was very helpful and we found that for some reason some of the parameters
were corrupted in the old single phase VFD.? Through this process I learned a lot about programming VFDs and I realized that the programming of the VFD was set to limit output current (the current limit of the original VFD) to 8.9A. The 5HP Baldor high efficiency
motor is rated at 11.8A.? In running the VFD and watching parameters I realized that the motor was never even getting to 60 HZ due to the current limit.
?
So I decided to upgrade the VFD to a 3 phase input. Same series ABB but at least with the ABB ACS310 series they are built as single phase input or
3 phase input.? So I ordered an ACS310 5HP 3 phase input VFD.? Super easy install as the programming just copies over.
?
But the new VFD faults.? Last week it would fault after a few minutes.? When measuring the input currents the delta then was about 30%.? Over the weekend
it didn’t fault at all and the current deltas were 20% or so. ?ABB sent a replacement VFD and it did not solve the issue.? Last night would get faults in less than a minute and the current delta was over 40%.
?
More background:
-
I have 600A of Utility 240V Delta 3 phase power.? Two transformers in my front yard.? New install one year ago with new buried lines from front yard to workshop.
-
The workshop has a 5 Ton AC, 1.5HP pool pump, and sometimes an AC and water heater on for the guest house, plus 2,200w of LED lighting.? I doubt I’d ever see more than 100A or load at
one time.
-
I have a 3 phase shaper and a 3 phase bandsaw running in the shop with no VFD and the currents are pretty consistent on all lines.
-
Voltage at the panel and at the VFD for all three legs is very similar.
-
When the utility came out this week to test I started as many loads in the shop as I could and we had 0.2V difference for the two transformer legs measuring 121.3V and 121.1V.? Leg B
being lower
-
It seems like the average current across the three legs is the same each time I measure even though the delta between legs can be quite different each time.
?
Can a phase error between the phases cause lower current in one leg?
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of imranindiana via groups.io
Sent: Friday, June 4, 2021 7:50 AM
To: [email protected]
Subject: Re: [FOG] VFD issue with 3 Phase power supply
?
More thoughts after rereading your post.
You mention original VFD as single phase and new as 3 phase input. This could be important if you are running with single phase input.
At first I thought you were running new VFD with single phase input but you report 3 input currents. Just curious, why are you using a VFD with 3 phase input on a dust collector with a 3 phase motor?
Another thought. I am sure you know this, on a VFD, the single or 3 phase input is used to create a DC power supply. This to me means that there should not be a repeatable phase relationship between input and output currents. A resolution
to your problem can help further our understanding of how these things work.
?
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
Once you verify the motor is fine without the vfd, and the utility power is balanced going into the vfd, it would seem the vfd is at least part of the problem.? I'm voting that the motor has issues until you rule that out.? Dave
toggle quoted message
Show quoted text
Some more background.? I brought the idea of variable speed to increase suction on small ports to Robert founder of Oneida at the Vegas show like 10 years ago.? We traded
a ton of emails and he swore me to secrecy and the idea became the Oneida Smart collector which won innovation of the year at either Vegas or Atlanta.? In appreciation for the idea Oneida upgraded my collector to a 5HP Smart collector, single phase input.
?
Lately I was having some issues with the 10 year old VFD shutting down and Oneida was very helpful and we found that for some reason some of the parameters were corrupted
in the old single phase VFD.? Through this process I learned a lot about programming VFDs and I realized that the programming of the VFD was set to limit output current (the current limit of the original VFD) to 8.9A. The 5HP Baldor high efficiency motor is
rated at 11.8A.? In running the VFD and watching parameters I realized that the motor was never even getting to 60 HZ due to the current limit.
?
So I decided to upgrade the VFD to a 3 phase input. Same series ABB but at least with the ABB ACS310 series they are built as single phase input or 3 phase input.? So
I ordered an ACS310 5HP 3 phase input VFD.? Super easy install as the programming just copies over.
?
But the new VFD faults.? Last week it would fault after a few minutes.? When measuring the input currents the delta then was about 30%.? Over the weekend it didn’t fault
at all and the current deltas were 20% or so. ?ABB sent a replacement VFD and it did not solve the issue.? Last night would get faults in less than a minute and the current delta was over 40%.
?
More background:
-
I have 600A of Utility 240V Delta 3 phase power.? Two transformers in my front yard.? New install one year ago with new buried lines from front yard to workshop.
-
The workshop has a 5 Ton AC, 1.5HP pool pump, and sometimes an AC and water heater on for the guest house, plus 2,200w of LED lighting.? I doubt I’d ever see more than 100A or load at
one time.
-
I have a 3 phase shaper and a 3 phase bandsaw running in the shop with no VFD and the currents are pretty consistent on all lines.
-
Voltage at the panel and at the VFD for all three legs is very similar.
-
When the utility came out this week to test I started as many loads in the shop as I could and we had 0.2V difference for the two transformer legs measuring 121.3V and 121.1V.? Leg B
being lower
-
It seems like the average current across the three legs is the same each time I measure even though the delta between legs can be quite different each time.
?
Can a phase error between the phases cause lower current in one leg?
?
?
More thoughts after rereading your post.
You mention original VFD as single phase and new as 3 phase input. This could be important if you are running with single phase input.
At first I thought you were running new VFD with single phase input but you report 3 input currents. Just curious, why are you using a VFD with 3 phase input on a dust collector with a 3 phase motor?
Another thought. I am sure you know this, on a VFD, the single or 3 phase input is used to create a DC power supply. This to me means that there should not be a repeatable phase relationship between input and output currents. A resolution to your problem can
help further our understanding of how these things work.
?
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
I am also going to lower the current limit in the programming to see what happens as it’s a really easy test.? The new VFD is rated for like 19.6A output
and I am only running at 11.8 so probably nothing but an easy test.
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of David Kumm
Sent: Friday, June 4, 2021 10:24 AM
To: [email protected]
Subject: Re: [FOG] VFD issue with 3 Phase power supply
?
Once you verify the motor is fine without the vfd, and the utility power is balanced going into the vfd, it would seem the vfd is at least part of the problem.? I'm voting that the motor has issues
until you rule that out.? Dave
Some more background.? I brought the idea of variable speed to increase suction on small ports to Robert founder of Oneida at the Vegas show like 10
years ago.? We traded a ton of emails and he swore me to secrecy and the idea became the Oneida Smart collector which won innovation of the year at either Vegas or Atlanta.? In appreciation for the idea Oneida upgraded my collector to a 5HP Smart collector,
single phase input.
?
Lately I was having some issues with the 10 year old VFD shutting down and Oneida was very helpful and we found that for some reason some of the parameters
were corrupted in the old single phase VFD.? Through this process I learned a lot about programming VFDs and I realized that the programming of the VFD was set to limit output current (the current limit of the original VFD) to 8.9A. The 5HP Baldor high efficiency
motor is rated at 11.8A.? In running the VFD and watching parameters I realized that the motor was never even getting to 60 HZ due to the current limit.
?
So I decided to upgrade the VFD to a 3 phase input. Same series ABB but at least with the ABB ACS310 series they are built as single phase input or
3 phase input.? So I ordered an ACS310 5HP 3 phase input VFD.? Super easy install as the programming just copies over.
?
But the new VFD faults.? Last week it would fault after a few minutes.? When measuring the input currents the delta then was about 30%.? Over the weekend
it didn’t fault at all and the current deltas were 20% or so. ?ABB sent a replacement VFD and it did not solve the issue.? Last night would get faults in less than a minute and the current delta was over 40%.
?
More background:
-
I have 600A of Utility 240V Delta 3 phase power.? Two transformers in my front yard.? New install one year ago with new buried lines from front yard to workshop.
-
The workshop has a 5 Ton AC, 1.5HP pool pump, and sometimes an AC and water heater on for the guest house, plus 2,200w of LED lighting.? I doubt I’d ever see more than 100A or load at
one time.
-
I have a 3 phase shaper and a 3 phase bandsaw running in the shop with no VFD and the currents are pretty consistent on all lines.
-
Voltage at the panel and at the VFD for all three legs is very similar.
-
When the utility came out this week to test I started as many loads in the shop as I could and we had 0.2V difference for the two transformer legs measuring 121.3V and 121.1V.? Leg B
being lower
-
It seems like the average current across the three legs is the same each time I measure even though the delta between legs can be quite different each time.
?
Can a phase error between the phases cause lower current in one leg?
?
?
More thoughts after rereading your post.
You mention original VFD as single phase and new as 3 phase input. This could be important if you are running with single phase input.
At first I thought you were running new VFD with single phase input but you report 3 input currents. Just curious, why are you using a VFD with 3 phase input on a dust collector with a 3 phase motor?
Another thought. I am sure you know this, on a VFD, the single or 3 phase input is used to create a DC power supply. This to me means that there should not be a repeatable phase relationship between input and output currents. A resolution
to your problem can help further our understanding of how these things work.
?
I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
|
Update. Another utility trouble shooter tech came by last night. This one was much more knowledgeable. He did not have a power quality meter or oscilloscope but he escalate to have a power quality tech come to test. More importantly he told me that “I didn’t
tell you this but we’ve had a ton of
Issues with the transformer we installed here”. He also told me that the power line behind my property where my transformers connect is scheduled for replacement and that they would only do that if there was an issue with being able to balance it. Also
learned that if you have more than 40mV of drop across fuses in a panel the fuse is bad and will fail.?
toggle quoted message
Show quoted text
On Jun 4, 2021, at 10:43 AM, Joe Jensen <joe.jensen@...> wrote:
?
I am also going to lower the current limit in the programming to see what happens as it’s a really easy test.? The new VFD is rated for like 19.6A output
and I am only running at 11.8 so probably nothing but an easy test.
?
?
Once you verify the motor is fine without the vfd, and the utility power is balanced going into the vfd, it would seem the vfd is at least part of the problem.? I'm voting that the motor has issues
until you rule that out.? Dave
Some more background.? I brought the idea of variable speed to increase suction on small ports to Robert founder of Oneida at the Vegas show like 10
years ago.? We traded a ton of emails and he swore me to secrecy and the idea became the Oneida Smart collector which won innovation of the year at either Vegas or Atlanta.? In appreciation for the idea Oneida upgraded my collector to a 5HP Smart collector,
single phase input.
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Lately I was having some issues with the 10 year old VFD shutting down and Oneida was very helpful and we found that for some reason some of the parameters
were corrupted in the old single phase VFD.? Through this process I learned a lot about programming VFDs and I realized that the programming of the VFD was set to limit output current (the current limit of the original VFD) to 8.9A. The 5HP Baldor high efficiency
motor is rated at 11.8A.? In running the VFD and watching parameters I realized that the motor was never even getting to 60 HZ due to the current limit.
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So I decided to upgrade the VFD to a 3 phase input. Same series ABB but at least with the ABB ACS310 series they are built as single phase input or
3 phase input.? So I ordered an ACS310 5HP 3 phase input VFD.? Super easy install as the programming just copies over.
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But the new VFD faults.? Last week it would fault after a few minutes.? When measuring the input currents the delta then was about 30%.? Over the weekend
it didn’t fault at all and the current deltas were 20% or so. ?ABB sent a replacement VFD and it did not solve the issue.? Last night would get faults in less than a minute and the current delta was over 40%.
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More background:
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I have 600A of Utility 240V Delta 3 phase power.? Two transformers in my front yard.? New install one year ago with new buried lines from front yard to workshop.
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The workshop has a 5 Ton AC, 1.5HP pool pump, and sometimes an AC and water heater on for the guest house, plus 2,200w of LED lighting.? I doubt I’d ever see more than 100A or load at
one time.
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I have a 3 phase shaper and a 3 phase bandsaw running in the shop with no VFD and the currents are pretty consistent on all lines.
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Voltage at the panel and at the VFD for all three legs is very similar.
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When the utility came out this week to test I started as many loads in the shop as I could and we had 0.2V difference for the two transformer legs measuring 121.3V and 121.1V.? Leg B
being lower
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It seems like the average current across the three legs is the same each time I measure even though the delta between legs can be quite different each time.
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Can a phase error between the phases cause lower current in one leg?
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More thoughts after rereading your post.
You mention original VFD as single phase and new as 3 phase input. This could be important if you are running with single phase input.
At first I thought you were running new VFD with single phase input but you report 3 input currents. Just curious, why are you using a VFD with 3 phase input on a dust collector with a 3 phase motor?
Another thought. I am sure you know this, on a VFD, the single or 3 phase input is used to create a DC power supply. This to me means that there should not be a repeatable phase relationship between input and output currents. A resolution
to your problem can help further our understanding of how these things work.
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I had to replace the VFD on my dust collector. It was an ABB ACS310 single phase input feeding a 3 phase 5 HP motor. This was from Oneida and because of the single phase supply they set the max current at the limit of the drive which is below the amperage
of the motor. Anyway the new drive, an ABB ACS310 5HP 3 phase input VFD, faults with my utility delta 3 phase supply. The fault is due to uneven current on the input. I’ve spent hours measuring and testing and worked with ABB tech support several times. The
key test ABB had me do was to swap two wires to see if the low current moves. It does not so ABB said not the drive. But they did approve a warranty swap. With the replacement I see the same problem. With leg A I get 20A leg B 15A and leg C 19A. Leg C is the
wild leg. The voltages under load for legs A and B are within 0.2V. I also had the utility out and then measured and said all good on their side. They did not put a scope on the lines to see is I have phase shift issues. Could a phase different between the
lines cause a 20-25% current difference when the voltages are the same? ?Also I have notices that the current difference changes. Worst was tonight with 22A, 14A, and 20A.?
also I have two other 3 phase machines that run and the currents measure the same on all three legs for those machines. I also tried running the VFD with a new breaker and also on a different line. ABB agreed to swap the drive because the currents are the same
on all legs with non-VFD machines. ?
the only thing I can think of is the phase angles between the three legs is not 120 degrees. HELP
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On Sat, Jun 5, 2021 at 08:17 AM, Joe Jensen wrote:
Also learned that if you have more than 40mV of drop across fuses in a panel the fuse is bad and will fail.
I can't guess what he meant.? Fuse is "bad" normally means "blown".? ?"is bad and will fail" really doesn't make much sense when talking about fuses. The most fundamental principle of electrical circuits, Ohm's law (V=IxR), says voltage drop across a conductor with a given Resistance (the fuse) varies directly with the current flowing, so measuring voltage drop across a hot fuse can serve as an ammeter.? Some fuse manufacturers publish fuse specs just so one can do this.? These reveal that 40mV voltage drop typically represents about 85% of the rated fuse current. Naturally, fuses come in all sorts of varieties.? Some are rated to blow at 75% of labeled rating, some at 100% (and of course on various time scales).? ?So measuring current at 85% on a fuse that should have blown at 75% would qualify as a fuse "fail" (extremely rare). On the other hand, for a fuse that blows at 100%, measuring it at 85% might quality as "near blowing", and after blowing it would be "bad", but then of course the fuse has worked correctly, so one can't say it "failed".
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Joe Jensen
imran