Powering three-phase skiver motor

[GerryR]

I don't know much about clutch motors but have assumed they run at full speed and that you "feather" the clutch to regulate the output(??).  If that is the case, then running it with a VFD is not a problem.  As stated above, you need to worry about low RPM because of the cooling.  Many "inverter rated" motors are spec'd at 10-90 Hz.  I have run many VFD's on fractional to 100+ Hp motors (factory automation).  I presently have one on an old Boyer-Shultz 3 ph. surface grinder in my shop (running full speed) that has been running for over 20 years, and I have a VFD running as my speed controller on my leather sewing machine; the sewing machine has an inverter-rated gear motor with a 5:1 reducer, so motor low-speed control is not a problem.  The point is you can use some form of reducer to raise the low-end motor RPM to keep it cooler.  I have recommended VFD's as optional speed controllers for sewing machines with clutch motors, lock the clutch on and use the VFD with a TIG welder footpedal to control the speed.  Many Tig welder footpedals have a built-in potentiometer for regulating output power which can be used to control the VFD output frequency.  Just some thoughts that might help if you run into problems.

(By the way, I'm using a unit similar to what you purchased (in my case 220VAC 1ph. in to 220VAC 3ph. out) and it works perfectly!)

[Tigweldor]

That is quite true.

The clutch on a clutch motor is just to feather it at the beginning. If you try to run a clutch motor at low speed for prolonged time - you will be riding the clutch a lot and the clutch lining will not last long.

And what you said about cooling - when running a clutch motor at low speed with a VFD - is equally true.

BUT : these old motors have massive copper windings and can stand the heat - unlike the cheap units from Chinesistan with aluminum windings.

The 550 Watt motor on my Adler 5-8 gets quite warm after prolonged operation - but it has held up for years now, with no consequence what so ever - I usually run it between 28 to 40 Hz - and we use 50Hz here in Germany straight out of the socket.

 

I mounted one of my VFDs (Fuji Frenic) to an aluminum plate so I can use it either on my Adler 5-8 , my Adler 4-4 or my Dürkopp 239-3

It has a 32 Amp socket - with an adapter 32 Amp to 16 Amp plugged into it in the pic.

The silver brake unit on the back of the VFD is not hooked up - have found no need for it on sewing machines.

Edited March 26 by Tigweldor

[GerryR]

That's a great idea, using one "portable" VFD to run multiple machines! 

[Tigweldor]

Here are some pics on what really impedes cooling - found in a sewing machine motor of a Pfaff 463  that came from a tailor (bought and repaired it for a lady friend of mine)

I find such a thing a potential fire hazzard as well - especially around electrical contacts.

Edited March 26 by Tigweldor

[Cumberland Highpower]

On 3/24/2025 at 4:34 AM, Digit said:

Thank you all for the replies.

Belgium is basically the sticks in the electro/mechanical field. Labour is so expensive over here that most small industries have moved away or went out of business decades ago and the associated tools have been sold off or scrapped. I'm also under the impression that over here there is very little interest in tinkering with stuff; that means there's not much of a second-hand market (complete machines or loose components) or scrap yards where you can find parts.
The skiver I've bought was actually a rare find, especially given its age. It was used by a now retired shoemaker and his successor prefers to use a more modern machine and sold this one. I've tested it in the seller's workshop and I was surprised by the reasonable quietness of the motor and the suppleness of the clutch.
The plate on the motor mentions the factory in Leinfelden which, according to the company's website, started in 1960. From 1985 they started making servo motors. Given this info and the motor's build quality I guess it must have been made somewhere in the sixties.

I'm not planning to install 3-phase power just yet. In Belgium there's 3ph arriving in most homes, but historically only one phase was hooked up and the utility companies alternated phases between houses to get them balanced. With the advent of electric cars and solar panels, new houses are more likely to get a proper 3-phase connection. Upgrading an existing single phase connection to three phases costs nearly as much as I paid for this skiver and would additionally require an inspection of the full electrical installation, which isn't free either.
Since there is an abundant supply of three-phase power in Belgium (albeit with a price tag), even to remote areas, and there has been for decades, there is no market for rotary phase converters (new or second hand).

@Cumberland Highpower I know I can run a three-phase motor on single phase using a Steinmetz connection (capacitors), but it's not very efficient and could risk overheating the motor by running it underpowered.

@Dwight I get what you're saying and it would make sense from a business perspective. However I do this as a hobby and for the moment I can still use the skivers at school, so there's no real pressure to get mine working. Also, contrary to most other Belgians, I do like to tinker with stuff and try things out.

@Tigweldor as I understand it, VFDs use an inverter to rectify incoming AC to DC and then produce simulated AC by pulsing DC (PWM) on successive phases; this pulsing can produce an audible whine in the motor, which you can reduce by tuning the carrier frequency. The VFD can produce 380V if it includes a step-up-converter in the DC line.

@Northmount I have no intention to run the motor on a different speed than it was made for, so cooling shouldn't be a problem as long as I vacuum the accumulated dust from the motor's grill. Anyway, the clutch allows me to tune the speed of the skiver using the pedal.

To conclude, I've ordered a single-phase 230V to three-phase 380V Chinese VFD and I'll see where that gets me. I'll keep you guys updated.

 

It would run at 2/3 power with the capacitors.     Probably not as bad as it sounds, my FAV came straight from Grande Italia this way.  I guess FAV didn't find it worthwhile to offer the FAV AV2 with a factory single phase motor at the time.   

[Cumberland Highpower]

1 hour ago, GerryR said:

That's a great idea, using one "portable" VFD to run multiple machines! 

It's kind of novel.  I wonder if you can find a ready made one somewhere like that?  Maybe with an extension cord already built in? a cord of 20' or so would be a plus, must hobby leather shops here in the US don't have 220v outlets as a standard thing so they maybe just wire up one.

If you have lots of 3ph machines, you'd be better off with a rotary phase converter and just wire your shop for 3ph.  That's what I have.   I can run every piece of machinery in there at once.  I have 2 converters, both surplus units from DuPont that cost $200. One is supposed to be a spare, but after 15 years I still don't need it.

Some machines can't work  properly on a single VFD,  for example a machine that has multiple seriously mismatched motor hp ratings or has motors that start and stop independently of each other.

Edited March 26 by Cumberland Highpower

[Tigweldor]

Every so often I work tearing down industrial plants - then usually behind an oxy-acetylene cutting torch.

But : my buds are electricians and so I get my VFDs for a few beer after work - can´t beat the price and I have yet to receive a defect unit from them.

[GerryR]

28 minutes ago, Cumberland Highpower said:

Some machines can't work  properly on a single VFD,  for example a machine that has multiple seriously mismatched motor hp ratings or has motors that start and stop independently of each other.

I have never seen a multi-motor machine running off of a single VFD; one motor per VFD.  Most VFDs require the motor parameters to be entered into it and it is only programmed for one set of motor parameters.  Besides, at the price of these VFDs these days, one per motor is pretty affordable, at least in the 5 hp and less range.

[Tigweldor]

I once bought one of these cheap VFDs from Chinesistan (that was years ago) - but as I mentioned before - they do not come with a built-in thermostat so the cooling fan runs all the time.

The one in mine was almost louder than the sewing machine at full speed - so I sent it back el pronto.

It does remind you to turn off power to the VFD at the end of work though.

Maybe they have fixed that "fault" in the meantime.

Edited March 26 by Tigweldor

[Cumberland Highpower]

On 3/26/2025 at 7:54 AM, GerryR said:

I have never seen a multi-motor machine running off of a single VFD; one motor per VFD.  Most VFDs require the motor parameters to be entered into it and it is only programmed for one set of motor parameters.  Besides, at the price of these VFDs these days, one per motor is pretty affordable, at least in the 5 hp and less range.

Controlling Multiple Motors with One VFD | Rockwell Automation | US

Here's a little primer on the basics

With the really cheap VFD's on Amazon/Alibaba and what not, that are pretty small, you'd probably be handicapped right out of the bubble wrap.  I don't use a VFD for anything, although I am warming up to the idea.  I've got one disc grinder I need to set up that is too far from my 3ph lines. A vfd would be cheaper than wiring/conduit, and it's within 20' of my 220v.

Edited March 27 by Cumberland Highpower