Hi Clive, I installed WEG motors on my Mill and Lathe back in the mid nineties in Australia and passed them onto my Brother who uses them daily without issues. TEFC, totally enclosed fan cooled so no dust or water ingress. The open frame motor is subject to the above. I use the same budget VFD's on my lathes, mill, drill press and compressor and no issues so far, hope to get 4 to 5 years out of them before the electrolytic capacitors dry out and expire. My Dean Smith & Grace had a Crompton Parkinson open frame motor and still going strong since 1954!!
I wondered if the open frame had allowed a build up of dust to affect cooling. I like the enclosed design, and the feel of the WEG motor is good. So far, I agree, that it seems like a good replacement. I will be keeping the budget VFD as back up for my other machines. Thanks for your feedback.
Nicely produced vid, I'm sure a lot of Colchester motors have reached the end of their working life and benefit from a up grade. I petricolid liked the custom finger thumb design for your wooden protector when bashing on the pully. .
Thank you! Yes I think you could be right about other similar vintage lathes needing an upgrade - though I think my motor may have had a harder time than most.
Excellent conversion, I'm sure your student will be very happy now. I have the same cheap vfd as you had in my mk 1 student, also with a 2.2kw motor. Performs very well so far. I mounted the vfd inside the switch box under the headstock. The only visible difference to the switch box is the addition of speed potentiometer and toggle switch for reverse ( my student was not reverse equipped), so it's set to factory spindle speed and left alone. I've heard these old motors were not designed to cope with the vfd setup, and the variable frequency can contribute to insulation breakdown. Humidity is a problem this time of year, we had a cold period, then it warmed again. One has to keep an eye on surface plates etc. I've been using a dehumidifier for many years now, couldn't really be without one.
I thought about mounting the VFD in the cabinet which would have made for a neat installation. The reason I didn't is because I was concerned about cooling and I wanted easy access to the front of the VFD for control. I suspect that once it is set up it probably will not be necessary to make adjustments. As for humidity; that might get better the subject of a future video with rust being the main problem! Thanks for your helpful comments, Constantine!
I did the same on my Student. New 2.2kw motor. New pulley (I don't have a spare lathe to re-bore the old one). And a new Bosch Rexroth VFD. I configured mine to use the original Colchester start/brake and reverse switch. I had read that it's potentially dangerous to use the VFD to control the spindle speed. At low motor RPM's the gears won't throw the gearbox oil up and into the bearing oilers. Bye bye expensive Gamet bearings😢 Regards, Preso
Thanks, Pres, for your helpful comments. I have kept the old reversing switch so I could set mine up in the same way. I did this on my pillar drill. As for the spindle speed I agree that caution is required. When I renovated this lathe I observed the oil splash with the cover off (carefully using the speed control!). I could see that the bearings rely on oil being thrown onto the underside of the cover and that much comes off the primary drive shaft. So, I agree that caution is required. The degree to which oil is thrown around is indicated by the oil level. I will be careful! Clive.
The type of failure you had on your motor is quit common on open frame electrical motors. Insulation degrades over time and extreme temperatures and humidity accelerate this process. However running these motors from a (cheap) vfd adds additional stress induced (no pun intended) by the harmonics present in the generated 3phase supply. Using the vfd to regulate speed is not advised, unless the motor has been designed and sized for this operation. Some nuance to the above: a home shop is not running continuously. I enjoy your channel a lot.
Thanks for your comments! I am learning something from all the feedback. I am wondering why open frame motors should be more susceptible to this kind of failure?
@@Workshopfriend Main reason: chemistry. Ingress of dirt and humidity deteriorate the insulation faster than in a sealed motor. In a sealed motor the atmosphere is not/less subject to change. Only thermal effects are dominant.
Another important consideration when using older motors with a VFD is its insulation class. Class "F" should be the minimum for a motor to be used with a VFD, your original motor may not be this high, and so could well be the reason for its insulation to fail, and exhibit the type of faults that you have observed. Your new motor will most likely be at least class "F".
I had heard that inverter power supplies can negatively impact older motor windings. After reading your comment I went to look up the insulation class of my new motor but haven't yet found it. I am hopeful it is rated for this application. I have one remaining older motor on a VFD drive (shaper) and was wondering if the frequency of the supply has an impact on damage ie 50Hz vs less?
From your meter readings it looks like there is a motor fault, but as you probably know it really needs a megger to test the insulation resistance properly. Be aware though that the vfd has a capacitor filter array which dumps any mains spikes to earth and these are notorious for tripping RCD’s! Phil
Thanks, Phil. Yes, as I was trying to take the measurements I realised that the inconsistent readings were an indication that my multimeter wasn't up to the task. Yes, one of my old VFD's would do that. I will be keeping the one I replaced as a backup/spares.
Hello Clive. Well done on achieving an excellent outcome. I really must look at replacing the motor on my Myford Super 7 with a three phase VFD upgrade. 👏👏👍😀
Good idea to go for a new motor. Even if you could fix the old one, it would still be an old motor and will start having problems again in a few years.
Hello Kit. I started machining from the age of 13 when my father bought me a little Drummond Round bed lathe. Later I did a Technician and Undergraduate apprenticeship with Rolls-Royce in Derby and worked for a while as a designer. Happy Christmas!
Hi Clive, I installed WEG motors on my Mill and Lathe back in the mid nineties in Australia and passed them onto my Brother who uses them daily without issues.
TEFC, totally enclosed fan cooled so no dust or water ingress.
The open frame motor is subject to the above.
I use the same budget VFD's on my lathes, mill, drill press and compressor and no issues so far, hope to get 4 to 5 years out of them before the electrolytic capacitors dry out and expire.
My Dean Smith & Grace had a Crompton Parkinson open frame motor and still going strong since 1954!!
I wondered if the open frame had allowed a build up of dust to affect cooling. I like the enclosed design, and the feel of the WEG motor is good. So far, I agree, that it seems like a good replacement.
I will be keeping the budget VFD as back up for my other machines. Thanks for your feedback.
Nicely produced vid, I'm sure a lot of Colchester motors have reached the end of their working life and benefit from a up grade.
I petricolid liked the custom finger thumb design for your wooden protector when bashing on the pully. .
Thank you! Yes I think you could be right about other similar vintage lathes needing an upgrade - though I think my motor may have had a harder time than most.
Nice work mister. He he. My motor /VFD on my lathe just packed up.
Thank you. Sorry to hear you have the same problem. Hope it doesn't cost too much to fix.
Excellent conversion, I'm sure your student will be very happy now. I have the same cheap vfd as you had in my mk 1 student, also with a 2.2kw motor. Performs very well so far. I mounted the vfd inside the switch box under the headstock. The only visible difference to the switch box is the addition of speed potentiometer and toggle switch for reverse ( my student was not reverse equipped), so it's set to factory spindle speed and left alone. I've heard these old motors were not designed to cope with the vfd setup, and the variable frequency can contribute to insulation breakdown.
Humidity is a problem this time of year, we had a cold period, then it warmed again. One has to keep an eye on surface plates etc. I've been using a dehumidifier for many years now, couldn't really be without one.
I thought about mounting the VFD in the cabinet which would have made for a neat installation. The reason I didn't is because I was concerned about cooling and I wanted easy access to the front of the VFD for control. I suspect that once it is set up it probably will not be necessary to make adjustments.
As for humidity; that might get better the subject of a future video with rust being the main problem!
Thanks for your helpful comments, Constantine!
I did the same on my Student. New 2.2kw motor. New pulley (I don't have a spare lathe to re-bore the old one). And a new Bosch Rexroth VFD. I configured mine to use the original Colchester start/brake and reverse switch. I had read that it's potentially dangerous to use the VFD to control the spindle speed. At low motor RPM's the gears won't throw the gearbox oil up and into the bearing oilers. Bye bye expensive Gamet bearings😢
Regards, Preso
Thanks, Pres, for your helpful comments. I have kept the old reversing switch so I could set mine up in the same way. I did this on my pillar drill.
As for the spindle speed I agree that caution is required. When I renovated this lathe I observed the oil splash with the cover off (carefully using the speed control!). I could see that the bearings rely on oil being thrown onto the underside of the cover and that much comes off the primary drive shaft. So, I agree that caution is required. The degree to which oil is thrown around is indicated by the oil level. I will be careful! Clive.
Another advantage of a modern motor is that the insulation is better able to handle the voltage from the inverter.
Thanks for your comment! Yes, that is my hope after the unexpected additional expense.
The type of failure you had on your motor is quit common on open frame electrical motors.
Insulation degrades over time and extreme temperatures and humidity accelerate this process.
However running these motors from a (cheap) vfd adds additional stress induced (no pun intended) by the harmonics present in the generated 3phase supply.
Using the vfd to regulate speed is not advised, unless the motor has been designed and sized for this operation.
Some nuance to the above: a home shop is not running continuously.
I enjoy your channel a lot.
Thanks for your comments! I am learning something from all the feedback. I am wondering why open frame motors should be more susceptible to this kind of failure?
@@Workshopfriend Main reason: chemistry.
Ingress of dirt and humidity deteriorate the insulation faster than in a sealed motor.
In a sealed motor the atmosphere is not/less subject to change.
Only thermal effects are dominant.
Well thank you for the explanation. I have learned something.
Another important consideration when using older motors with a VFD is its insulation class. Class "F" should be the minimum for a motor to be used with a VFD, your original motor may not be this high, and so could well be the reason for its insulation to fail, and exhibit the type of faults that you have observed. Your new motor will most likely be at least class "F".
I had heard that inverter power supplies can negatively impact older motor windings. After reading your comment I went to look up the insulation class of my new motor but haven't yet found it. I am hopeful it is rated for this application.
I have one remaining older motor on a VFD drive (shaper) and was wondering if the frequency of the supply has an impact on damage ie 50Hz vs less?
From your meter readings it looks like there is a motor fault, but as you probably know it really needs a megger to test the insulation resistance properly. Be aware though that the vfd has a capacitor filter array which dumps any mains spikes
to earth and these are notorious for tripping RCD’s!
Phil
Thanks, Phil. Yes, as I was trying to take the measurements I realised that the inconsistent readings were an indication that my multimeter wasn't up to the task. Yes, one of my old VFD's would do that. I will be keeping the one I replaced as a backup/spares.
Hello Clive. Well done on achieving an excellent outcome. I really must look at replacing the motor on my Myford Super 7 with a three phase VFD upgrade. 👏👏👍😀
Thank you, Andrew. Yes, I found the 3-phase inverter drive is a great asset in a home workshop. Perhaps a project for the New Year!
@@Workshopfriend Definitely high on the list.
Good idea to go for a new motor. Even if you could fix the old one, it would still be an old motor and will start having problems again in a few years.
Yes, I have to admit that was a factor in my thinking. Plenty of other things to do!
Clive how did you start in machining a apprenticeship and were did work in your early years !
Kit from down under
Hello Kit. I started machining from the age of 13 when my father bought me a little Drummond Round bed lathe. Later I did a Technician and Undergraduate apprenticeship with Rolls-Royce in Derby and worked for a while as a designer.
Happy Christmas!
If you load the motor with 2.2kW, your supply will send a SOS signal very fast.
I hope not, but please enlighten me. Thanks!