# GE Fuji drive problem



## wendon (Sep 27, 2010)

We recently installed a GE Fuji drive that is connected to a blower pump. It had formerly been installed in a different location and had worked fine. It is being controlled by a separate control (4-20 ma) that maintains a vacuum level. The drive is always left in the "run" mode and the start/stop is evidently controlled by the 4-20 ma. The problem is that when the controller is shut off, the drive continues to run the motor at low speed (28 hz). If you put your hand over the blower pump exhaust and stall out the motor, it stops the motor until the next cycle. I disconnected the 4-20 ma cable at the controller but the motor continued to run. Any ideas? I'm not too familiar with this brand of drive.


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## hardworkingstiff (Jan 22, 2007)

wendon said:


> The problem is that when the controller is shut off, the drive continues to run the motor at low speed (28 hz).


Wendon, the "controller" is what? I'm assuming the controller is not the drive you are talking about since the drive continues to run the motor.

Or, are you turning off power to the controller it still is running the motor?


Sorry for my confusion, and I most likely won't be able to help you with the drive.


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## wendon (Sep 27, 2010)

hardworkingstiff said:


> Wendon, the "controller" is what? I'm assuming the controller is not the drive you are talking about since the drive continues to run the motor.
> 
> Or, are you turning off power to the controller it still is running the motor?
> 
> ...


The controller is a separate unit. It has a vacuum display built into it. It is controlled by a 120 vac input. When the 120 volt input is disconnected, the motor is supposed to stop. The drive comes preconfigured from the company.


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## hardworkingstiff (Jan 22, 2007)

wendon said:


> The controller is a separate unit. It has a vacuum display built into it. It is controlled by a 120 vac input. When the 120 volt input is disconnected, the motor is supposed to stop. The drive comes preconfigured from the company.



Do you understand how the controller is supposed to be telling the drive to turn off?

Since the drive was working somewhere else, could it have lost some programmed settings while in transit?

Just tossing up ideas, I'm sure you are way past my simplistic thoughts.


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## wendon (Sep 27, 2010)

hardworkingstiff said:


> Do you understand how the controller is supposed to be telling the drive to turn off?
> 
> Since the drive was working somewhere else, could it have lost some programmed settings while in transit?
> 
> Just tossing up ideas, I'm sure you are way past my simplistic thoughts.


The only control is a 2 wire cable connected to the 4-20ma input on the drive so I assume they're using that. The drive is always left in the "run" mode.


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## hardworkingstiff (Jan 22, 2007)

wendon said:


> The only control is a 2 wire cable connected to the 4-20ma input on the drive so I assume they're using that. The drive is always left in the "run" mode.


So it must be that the intent is when the controller is shut down, the 4-20ma circuit loses power and the drive sees "0" ma, and is supposed to shut off, right?

Is the power source for the 4-20ma circuit in the drive or in the controller?


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## hardworkingstiff (Jan 22, 2007)

Did you see it work the way you described (drive turning off instead of running the motor slow) or is someone telling you that's how it worked?


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## wendon (Sep 27, 2010)

hardworkingstiff said:


> So it must be that the intent is when the controller is shut down, the 4-20ma circuit loses power and the drive sees "0" ma, and is supposed to shut off, right?
> 
> Is the power source for the 4-20ma circuit in the drive or in the controller?


I think that's correct.


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## wendon (Sep 27, 2010)

hardworkingstiff said:


> Did you see it work the way you described (drive turning off instead of running the motor slow) or is someone telling you that's how it worked?


I didn't see it run in the previous location but it seemed to work normal when we cycled it the first few times. I'm thinking it would be better to incorporate a separate relay to the start/stop inputs on the drive in addition to the other control.


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## wendon (Sep 27, 2010)

wendon said:


> I think that's correct.


I'm not sure which end is powering the circuit.


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## psgama (Oct 26, 2015)

Check your settings for minimum speed on the drive. Seems to me like your minimum speed is not set to 0 rpm / 0 hz. Also there should be a setting for loss of signal action. At least with the drives I've programmed. Break out the manual and/or the software and plug in to the drive. See what's going on.


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## emtnut (Mar 1, 2015)

wendon said:


> We recently installed a GE Fuji drive that is connected to a blower pump. It had formerly been installed in a different location and had worked fine. It is being controlled by a separate control (4-20 ma) that maintains a vacuum level. The drive is always left in the "run" mode and the start/stop is evidently controlled by the 4-20 ma. The problem is that when the controller is shut off, the drive continues to run the motor at low speed (28 hz). If you put your hand over the blower pump exhaust and stall out the motor, it stops the motor until the next cycle. I disconnected the 4-20 ma cable at the controller but the motor continued to run. Any ideas? I'm not too familiar with this brand of drive.


Do you have the Model of drive ? I can take a peek at the manual.
I think these units have a bias frequency that should be set to zero for your application.


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## wendon (Sep 27, 2010)

emtnut said:


> Do you have the Model of drive ? I can take a peek at the manual.
> I think these units have a bias frequency that should be set to zero for your application.


I believe it's an AF 300. Not sure. The company that sells the package calls it a Frenic inverter. I did find a note on one of their manuals that said they've had a problem with these drives staying "latched" for the 4-20 ma signal due to external noise. The fix was to change the start/stop parameter to external and install a set of dry contacts to switch it. I'll probably have to persue that. The only factory set parameter that I could see had been changed was F26. The factory default was 8 khz and it had been changed to 15 khz.


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## hardworkingstiff (Jan 22, 2007)

wendon said:


> The fix was to change the start/stop parameter to external and install a set of dry contacts to switch it.


Gee, where did I hear that before, 

That sure sounds like the most reliable solution. 
But old farts think that way.


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## emtnut (Mar 1, 2015)

wendon said:


> I believe it's an AF 300. Not sure. The company that sells the package calls it a Frenic inverter. I did find a note on one of their manuals that said they've had a problem with these drives staying "latched" for the 4-20 ma signal due to external noise. The fix was to change the start/stop parameter to external and install a set of dry contacts to switch it. I'll probably have to persue that. The only factory set parameter that I could see had been changed was F26. The factory default was 8 khz and it had been changed to 15 khz.


F26 is just the step frequency.
If you haven't already, make sure that the 'drain' wire on your control cable is ONLY connected at the drive, and not connected at the control source.


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## emtnut (Mar 1, 2015)

hardworkingstiff said:


> Gee, where did I hear that before,
> 
> That sure sounds like the most reliable solution.
> But old farts think that way.


I old and fart lots too  
That's the preferred setup if you ask me :thumbsup:


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## JRaef (Mar 23, 2009)

At a 15kHz carrier frequency, you likely have to de-rate the drive and possibly the motor. Also, a high carrier frequency like that will create a lot more RFI (Radio Frequency Interference) around the VFD itself. So if, in the old installation, they used unshielded wire on the 4-20mA loop and it worked fine, increasing the CF may have created this new problem. 

There is usually no real good reason to do that. It appears to make the motor run quieter, but really it just increases the pitch of the whine sound out of the range of human hearing. The down side of increasing it is more switching losses and more RFI. Put it back down to where it was. Most motors are on machinery that makes more noise anyway. If someone really can't stand the whine, make sure your signal wires are done with shielded twisted pairs, and consider adding an EMI/RFI filter to the drive.


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## wendon (Sep 27, 2010)

emtnut said:


> F26 is just the step frequency.
> If you haven't already, make sure that the 'drain' wire on your control cable is ONLY connected at the drive, and not connected at the control source.


They actually had shielded cable and I did try it with the drain connected at the drive end but it still didn't work. Thanks for the advice!:thumbup:


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## wendon (Sep 27, 2010)

JRaef said:


> At a 15kHz carrier frequency, you likely have to de-rate the drive and possibly the motor. Also, a high carrier frequency like that will create a lot more RFI (Radio Frequency Interference) around the VFD itself. So if, in the old installation, they used unshielded wire on the 4-20mA loop and it worked fine, increasing the CF may have created this new problem.
> 
> There is usually no real good reason to do that. It appears to make the motor run quieter, but really it just increases the pitch of the whine sound out of the range of human hearing. The down side of increasing it is more switching losses and more RFI. Put it back down to where it was. Most motors are on machinery that makes more noise anyway. If someone really can't stand the whine, make sure your signal wires are done with shielded twisted pairs, and consider adding an EMI/RFI filter to the drive.


Thanks! I'll probably try that first. It won't be too big of a problem to install a relay and replace the 18-2 with a 18-4.


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## chknkatsu (Aug 3, 2008)

i've never heard of using a 4-20ma for start/stop before. whenever we do VFD's with hardpoints the startstop is usually just a dry contact off a controlled or relay and the speed control is a separate 18/2. but i'm sure there are other ways


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## John Valdes (May 17, 2007)

chknkatsu said:


> i've never heard of using a 4-20ma for start/stop before. whenever we do VFD's with hardpoints the startstop is usually just a dry contact off a controlled or relay and the speed control is a separate 18/2. but i'm sure there are other ways


The 4-20ma input is for speed not for start/stop.
What he says, is the drive is left in the "run" mode and the 4-20ma signal is used to adjust the speed. 
If 4ma equals zero speed and 20ma is max speed then the drive should stop the motor when it sees 4ma.

Start/Stops are digital inputs and can be internal contacts or external contacts. You are correct. You do not give a start command with the ma input. You must already be in the "run" mode or any other operational mode to be able to start and stop the motor with the speed reference (4-20ma).


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## chicken steve (Mar 22, 2011)

Not that i'm any help , but we did have a similar problem with a freq drive being _'sensitive_' , the VFD cable was placed in metallic conduit , and it still didn't work.

My _highly unqualified_ input was to simply start turning things off within the M.E.N. facility in order to pinpoint the culprit


~CS~


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## gesparky221 (Nov 30, 2007)

I would check he 4-20ma circuit. With the drive left in the run mode if there is any noise on the 4-20ma circuit the drive would try and keep the motor running. There is also a parameter in the drive if I remember to select the speed ref input. I seem to remember it had several settings including 0-20 ma, along with 4-20, 0-10, and so on. If you have 0-20ma selected that may explain why it is still moving. I never like to have a motor sitting at zero speed and the run circuit energized. It may cause someone to think it is off when it is only sitting there at zero speed waiting on a reference to speed up.


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## wendon (Sep 27, 2010)

gesparky221 said:


> I would check he 4-20ma circuit. With the drive left in the run mode if there is any noise on the 4-20ma circuit the drive would try and keep the motor running. There is also a parameter in the drive if I remember to select the speed ref input. I seem to remember it had several settings including 0-20 ma, along with 4-20, 0-10, and so on. If you have 0-20ma selected that may explain why it is still moving. I never like to have a motor sitting at zero speed and the run circuit energized. It may cause someone to think it is off when it is only sitting there at zero speed waiting on a reference to speed up.


I tried a number of things; grounding the drain wire, shutting off other circuits etc. to no avail. Owner says it's working properly now. Must have been gremlins. In my opinion, it's still not wired correctly even if the OEM installation manual shows it wired that way.


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## JRaef (Mar 23, 2009)

I don't know why I didn't think of this before, but reading your initial description triggered it this time.

A lot of VFDs now have a "sleep" feature that monitors the load on the drive and if the load goes away for a period of time, it turns off the output, but the drive is technically still in a Run condition. So if, for example, your 4-20ma signal goes to 4mA, the minimum from the controller, that triggers the drive to run at a minimum speed for a period of time and if the signal doesn't go up, or the load on the motor drops even further, the drive frequency goes to zero.



> ... The problem is that when the controller is shut off, the drive continues to run the motor at low speed (28 hz). If you put your hand over the blower pump exhaust and stall out the motor, it stops the motor until the next cycle. I disconnected the 4-20 ma cable at the controller but the motor continued to run. ...


So that actually might be exactly how this is SUPPOSED to act. With no signal from the controller, either because you turned it off or disconnected it, the Sleep function timer is initiated and if left that way long enough, would eventually turn off. But by putting your hand on the outlet of the blower, you are making the LOAD go away (flow = load, no flow = no load), which overrides the timer and shuts down.


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## wendon (Sep 27, 2010)

JRaef said:


> I don't know why I didn't think of this before, but reading your initial description triggered it this time.
> 
> A lot of VFDs now have a "sleep" feature that monitors the load on the drive and if the load goes away for a period of time, it turns off the output, but the drive is technically still in a Run condition. So if, for example, your 4-20ma signal goes to 4mA, the minimum from the controller, that triggers the drive to run at a minimum speed for a period of time and if the signal doesn't go up, or the load on the motor drops even further, the drive frequency goes to zero.
> 
> So that actually might be exactly how this is SUPPOSED to act. With no signal from the controller, either because you turned it off or disconnected it, the Sleep function timer is initiated and if left that way long enough, would eventually turn off. But by putting your hand on the outlet of the blower, you are making the LOAD go away (flow = load, no flow = no load), which overrides the timer and shuts down.


This is a lobe style blower pump so I believe covering the exhaust would raise the load, correct? I tried disconnecting 4-20 ma signal wire from the sensor end but it still continued to run. The OEM manual explained that there were know issues with this system. They explained it that, due to "noise" the drive would "clamp" on to a certain frequency even though the 4-20 ma source was shut off. I also shut off all the other breakers except the ones controlling the drive and the controller. I would have liked to try disconnecting the control wire from the drive but the keypad is built into the cover. The company's solution was to install a dry set of contacts to switch the start/stop function of the drive, which is what they should have done originally.


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## John Valdes (May 17, 2007)

wendon said:


> This is a lobe style blower pump so I believe covering the exhaust would raise the load, correct? I tried disconnecting 4-20 ma signal wire from the sensor end but it still continued to run. The OEM manual explained that there were know issues with this system. They explained it that, due to "noise" the drive would "clamp" on to a certain frequency even though the 4-20 ma source was shut off. I also shut off all the other breakers except the ones controlling the drive and the controller. I would have liked to try disconnecting the control wire from the drive but the keypad is built into the cover. The company's solution was to install a dry set of contacts to switch the start/stop function of the drive, which is what they should have done originally.


I worked in a plant full of these lobe blowers. But we used ours for suction.
To move material to manufacturing lines.
No local PLC control as this was a system. 

Ever had to send one out for repair? Mechanical repair?
I only knew one machinist that would touch them. The lobes that is.


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## wendon (Sep 27, 2010)

John Valdes said:


> I worked in a plant full of these lobe blowers. But we used ours for suction.
> To move material to manufacturing lines.
> No local PLC control as this was a system.
> 
> ...


This one is used for vacuum on a dairy. The pump is variable speed to maintain a set vacuum level. They work very well for this app. The tolerances are extremely critical on these pumps.


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## Cow (Jan 16, 2008)

The dairies I do work for all use Pumpmaster II controllers by Etron for their vacuum pumps. The last ones I worked on, the customers employees hosed both of the Nema 1 Fuji VFD's down so I got the pleasure of replacing them with ABB's. I believe I set them up for one digital input giving a start/run signal and 0-10v for an analog speed reference.

I didn't see where you said which controller you're using but I find it odd you don't have a seperate run signal to the drive in addition to the speed reference. I've worked with quite a few drives and have never used the speed reference as a start/stop command also.


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## John Valdes (May 17, 2007)

Cow said:


> I didn't see where you said which controller you're using but I find it odd you don't have a seperate run signal to the drive in addition to the speed reference. I've worked with quite a few drives and have never used the speed reference as a start/stop command also.


I have seen this on a couple occasions.
Drive in operational mode waiting for a speed reference.
Kinda like a jog scenario.
I guess it just depends on the application. Its amazing all the things we can do.


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