VFD - Where lies the problem

I have an Invertec Optidrive E3 vfd, and it has been driving my mill for just over 2 years now.The motor shaft on the mill driving the pulley suffered serious damage recently. The drive was through a grub screw(I know not good) & I had ignored the occasional noises coming from the vicinity of the motor. I had to remove the armature to clean up the shaft, & fabricate a better drive to the pulley. The motor is now back on the mill & connected to the vfd. I have gone through the parameter settings, & there are three mometry switches controlling Fwd,Reverse & stop & a 10k 10 turn potentiometer. The problem I am now experiencing is that on the default frequency of 50Hz & the pot on max, the vfd shows 1.6Hz and the motor revs are low, somewhere about 20 to 30 revs. If I change the po1 setting to 500Hz which is the max setting,the vfd shows 16.6Hz the motor turns faster but is not a usable speed. The pot does reduce the speed, which suggests to me it is ok. So what do people think is the motor on its way out, or does the fault lie with the vfd, though no fault code has ever been displayed. I would appreciate your thoughts. Regards Lynne

If it was working OK previously, first question is what has changed? Could any of the wiring have been connected differently to how it was previously connected - either to motor or to controls? Any loose wires?

Could the VFD be in 'jog' mode?

Is motor free to rotate by hand without undue friction?

You may have been unlucky and a VFD fault occurred whist motor was removed, but I'd first check for anything that might have been changed unintentionally whilst working on the motor.

Has the unit lost it's parameters and needs re setting ? 16.6 Hz is one third of 50Hz ! Lost 2 phases ? Noel.

Oh Dear - 2 phases down it is not going to even move

Loss of a phase won't affect the frequency.

Sounds like a configuration issue. If a record was kept of the settings required it is best to do a full factory reset and re-enter them all.
Just re-entering or checking may not help because it could be a different setting or even one which is un-documanted.

Robert.

Re setting, as Robert advises will be a good start, and I checked The Inverter Drive Supermarket and there is one of their "quick start guides" for this model which tells you how to reset the inverter. The original manufacturers manual is also there and both can be printed out. As for the pulley on the motor, my fix was two grub screws fitting into the milled down key. A reinforcing sleeve was pressed onto the pulley to allow longer threads for the grubscrews.

**LINK**

Edited By old mart on 21/04/2023 20:57:58

My thanks to all who have responded to my post. When I installed the vfd I did use the Inverter Drives set up parameters & as i said in post it has been working fine for two & a half years. After the pulley trauma I did check the vfd parameter settings, & they were all over the place, but at this point repair of the shaft was my priority. The wiring to the motor was only removed at the vfd & I don't think that the phases are connected to the vfd in any particular order, only to reverse two phases if the direction is not correct. The switches are wired correctly as they work fine. I did reset the defaults to the factory settings & then followed the Inverter Drives parameter set up chart. I do have access to mains 3 phase but it means removing the motor & transporting it elswhere, but at least that will prove out the motor. OLD MART. Thanks for posting the pictures & link. I am still using the one grub which locates onto an area of flat on the shaft, & I will up this to two. I like the key, but I do not have a big dia of shaft to play with. No one has suggested that the vfd is faulty, & , if it is faultyI am reluctant to shell out on a new vfd two and a half years is poor. I still have the original motor, & I did'nt ditch the belt system. Regards, Lynne

If you have a multimeter, you could check out the motor wiring for continuity, equal resistance between phases and for any short to earth.

Personally, I doubt that the VFD has gone bang - unless you shorted its output while it was still switched on. It sounds to me that when going through the settings, you accidentally changed a parameter somewhere. For example; output frequency range?

Or disturbed the motor brushes or reassembled the motor incorrectly maybe? Does the shaft spin freely by hand?

Old Mart. Thanks or the suggestion to check out the motor phases using a meter. Why did'nt I think of that, it just shows that I am not switched on electrically.

john Doe2 I did put the vfd back to the factory settings,so I think anything along the lines you suggested should have been resolved. No motor brushes, & the motor spins freely. I will double check the default settings that I have entered using the the Inverter Drives guide sheet. Regards, Lynne

A picture of the motor plate would be helpful. The original post mentions an armature, which implies a DC motor. But a later post says no brushes. Is the motor brushless DC or induction?

Andrew

Andrew,

Perhaps Lynne has misnamed the rotor, using a VFD seems like a 3 phase AC induction motor.

Emgee

That would be a sensible assumption. But I learnt long ago that the key to solving problems is not to make assumptions but is to verify facts. Hence the question about the motor type.

Andrew

Sorry, I clearly do not know the difference between rotor & armature. There is a picture of the motor name plate in my albums under the heading RDM 350. I have tried inserting this into this post but have failed.I got as far as looking for 'insert', but where is it?. I guess there are explict instructions somwhere. Lynne

Thank you, that confirms that the motor is 3-phase induction. Although a pain it would be worthwhile connecting the motor to a proper 3-phase supply to eliminate any issues with the motor. The motor will need to be connected in star for connection to the 3-phase supply, and then back to delta for connection to the VFD.

Andrew

The photo is of a 3 phase induction motor.

The described fault is not a motor issue and is unlikely to be a gross fault in the VFD.
Can you measure tha voltage across the 10 turn pot (CW and CCW terminals) It should be10V DC. I think it is most likely that the pot or it'a wiring is at fault. If the voltage across the pot is corrrect measure between the CCW and wiper terminals with the pot set to 50% and 100%.
Check again at the VFD terminals (7 is 0V / CCW, 6 is input / wiper, 5 is +10V CW). Be VERY CAREFUL measuring on the VFD terminals. Some may have hundreds of volts on them,. This may be present for several minutes after you turn it off.

Alternatively set the speed from the control panel rather than using the potentiometer (analog) input and see what it does.
If you tell us the full model / part number of the VFD I'll check the manual, but it looks like you have to change P12 to 2 to enable the control panel.

To go back to the pot Set P12 to 0 and P15 to zero.

Also check:
P16 = U0-10
P35 = 100%
P39 = 0

Robert.

Edited By Robert Atkinson 2 on 25/04/2023 17:18:48

Edited By Robert Atkinson 2 on 25/04/2023 17:24:05

Since nobody else has, how to post photos is here.

Rob

Links to https://www.model-engineer.co.uk/forums/postings.asp?th=103028&p=1

Thanks to you all for the replys.

Robert Atkinson. The vfd description is:- Invertec Optidrive E3 IP20 -0.75kW 230v 1ph to 3ph AC Inverter drive.

pt no. ODE-3-120043-IF12 Thanks also for the detailed test routine to check out the pot. Very useful for me.

Not able to check it out today, but will get back with results SAP. Regards, Lynne

Hi Robert, voltage across the pot terminals cw-ccw is 10v. The voltage between ccw & wiper terminals is 50% 5v & 100%10v. Have checked P16, 35 &39, & they are ok. Lynne.

Hi,

So the Pot is OK

Have you tried setting P12 to 2 and entering a percentage speed from the front panel?

P01 needs to go bck to 50Hz.

Robert.