220 volt BLDC motor

[Mjolinor]

I have a couple of milling machines that are ex military. When the military in the UK attach the word "EX" it basically means cut as many wires as you can to stop other people using it.

I have spent some time rewiring and am sure that the controller is not working so need to find another that will do the job. There are several options for this but I do have some VFDs for normal 3 phase motors and if possible it would make sense to use one of those.

The motor says 1100 watts 220 volts so will that be 220v phase ground or 220v phase phase. Obviously if it is phase phase then a mains operated VFD will blow it up. I cannot find any reference to the motor or the controller that I have on t'interweb anywhere.

[H.O]

The voltage rating of the motor would be between phases and unlike most induction motors you generally can't rewire the motor, (as in wye/delta configuration). Also, an ordinary VFD can't usually run permanent magnet (BLDC, PMAC) motors. There are high-end ones that can but I think you'd know if you had one of those - then again, perhaps you do.

[Mjolinor]

Not likely to be high end.

I actually mended one of the controllers. A blown w005 bridge rectifying mains!!!!!!

It is one very similar to this: https://www.amadeal.co.uk/acatalog/Amadeal-VM32LV-Milling-Machine.html

Mine has Weiss written on it.

I didn't think I would be able to repair the controllers as they are seriously potted but some heat, some poking, scraping, Dremel etc etc ( I am sure you have all been there) and I managed to get the stuff off. Having done one I just removed the potting on the area of the bridge on the second one and sure enough, same fault on the second one.

Problem solved.

[H.O]

Ha, how strange is that, I just took delivery of a lathe from Amadeal and my first reaction during inspection was how freakin' small the spindle motor is considering it's rated 1.5kW (I have a hard time believing that rating...) - and indeed the controller is potted.

Would you care to share an image or two of your controller and where you dug into it?

[Mjolinor]

http://rollingpast.com/john/mill/1.jpg
http://rollingpast.com/john/mill/2.jpg

Unfortunately the second one has more faults. The small bridge rectifier drives a VIPer22A PWM voltage regulator do dad that makes 12 volts ish from the rectified mains. That in turn drives into a 7805. The 7805 was blown so some more digging and stuck a  new one in and now it is not getting hot like it was but still isn't giving me the BLDC out. It does now have the 5 volt needed for the hall inputs and other stuff so making progress. Hoping it is not the driver transistors, they are seriously potted top and bottom and middle so it will be serious hard work to get them out successfully.

[Mjolinor]

It is looking terminal now.

The 7805 drives directly into an STM8S micro so given that the 7805 went short from 12 volt input to 5 volt output the STM8S will be toast and there is nothing I can do to fix that short of removing it from the other controller, reading it (probably locked so not likely) and programming a new one.

Still, buying one is better than buying two.

[H.O]

Yeah, and perhaps get one that lasts - or replace the motor AND drive. Thanks for the photos!

[Zero999]

If you're thinking about replacing the motor anyway, then why not try a standard induction motor drive? If the original inverter just used used rectified mains, no buck converter or anything and the motor is rated 220V phase-to-phase, which should be the case if it only has three wires, it should be fine.

[james_s]

Ha, how strange is that, I just took delivery of a lathe from Amadeal and my first reaction during inspection was how freakin' small the spindle motor is considering it's rated 1.5kW (I have a hard time believing that rating...) - and indeed the controller is potted.

Would you care to share an image or two of your controller and where you dug into it?

BLDC motors can be enormously powerful for their size. I have electric model airplanes with 500W motors that are physically about half the size of a D battery. I know guys who have larger planes with multi-kW motors that would fit in the palm of my hand. I haven't seen your lathe motor but it's entirely possible that the rating is legitimate.

[Mjolinor]

Size is the problem. The BLDC lathe motor is about 90mm diameter and 110mm tall, rated at 1100 watts, the 750 watt mill motor is not much smaller than that. If I stuck a normal AC motor on there of comparable power the mill would look ridiculous and fall over all the time like I do when I drink.

There are lots of choices form China at £100 a pop but we all know the risks invovled with that path.

[james_s]

At that size I can easily believe the power ratings. You can get 3+ kW BLDC motors that are about that size.

[H.O]

But I bet those airplane motors that can deliver a kW or more won't be able to do so for very long without the airflow automatically created.

I took another look at the motor on my lathe and it's aproximately 90mm square/round(ish) and 125mm long so a slightly larger than the 1100W version mentioned. I'll give it the benefit of a doubt but if/when it fails I'll replace it with something like a 130ST-M10025 from AliExpress.

[Mjolinor]

I don't think the motor will ever be a problem but finding a replacement controller is proving tedious. Lots to choose from and nothign to say which is better than the rest.

[james_s]

But I bet those airplane motors that can deliver a kW or more won't be able to do so for very long without the airflow automatically created.

True, they need good cooling, but that is not impossible to build into a compact motor. I have not seen this specific motor so I can't say whether the rating is realistic. My point is only that it is possible to make a motor that powerful in that physical size.

[NiHaoMike]

I don't think the motor will ever be a problem but finding a replacement controller is proving tedious. Lots to choose from and nothign to say which is better than the rest.

Have you considered an Openinverter board driving an integrated power stage?
https://openinverter.org/docs/index.html

[H.O]

I haven't seen Openinverter project before but it looks to  me as if it's designed for induction motors - ie it's a variable frequency drive with V/f control like any normal VFD and so is not suitable for permanent magnet motors.

[Zero999]

But I bet those airplane motors that can deliver a kW or more won't be able to do so for very long without the airflow automatically created.

I took another look at the motor on my lathe and it's aproximately 90mm square/round(ish) and 125mm long so a slightly larger than the 1100W version mentioned. I'll give it the benefit of a doubt but if/when it fails I'll replace it with something like a 130ST-M10025 from AliExpress.

They also run at an extra low voltage, so will need big, chunky cables and there might not be room for them.

[NiHaoMike]

I haven't seen Openinverter project before but it looks to  me as if it's designed for induction motors - ie it's a variable frequency drive with V/f control like any normal VFD and so is not suitable for permanent magnet motors.

It can also work with permanent magnet motors like the ones salvaged from EVs.

[Mjolinor]

That open inverter thing looked interesting until I looked at the price. :eek:

Too many features that I don't need I think.

I am sitting here wondering if these 36 volt 500 watt controllers that I have lying about could be driven into a transformer and then into the 220 volt BLDC motor. Timing would be a bit strange but the Hall feedback should compensate.

I ordered this one:
https://www.aliexpress.com/item/33006976568.html?spm=a2g0s.9042311.0.0.350c4c4dSHZV4T

[NiHaoMike]

That open inverter thing looked interesting until I looked at the price. :eek:

It's open source, build your own!