Powering three-phase skiver motor

[GerryR]

I was told it could be done, just have never seen it done.  From the article linked, it is very involved; unless you are running some large motors with very expensive VFDs (for which Rockwell Automation is noted for) I think it would be cheaper and safer to use one VFD per motor.  But, thanks for the link; never to old to learn something new!

[Tigweldor]

I myself can only use one sewing machine at the time - so I see it as a very minor problem  to unplug one socket and plug in another when switching to a different machine.

After all - I´m a hobbyist and don´t have to run a commercial set up with multiple machines being run simultaneously.

But yes, it is nicer to have a VFD for every machine - on the other hand, I have additional hobbies as well - coin sunk into one hobby will directly affect how much I can spend on my other projects.

That is the way I look at it - some times you have to improvise and be frugal. Latter does not mean being cheap - it does however mean to consider/plan how available coin is spread most cost effective.

And the chance of industrial tear downs with a booty of one or two "free" VFDs does not come along every day - my crystal ball is kind of cloudy right now as to when it will happen again. So I´m back to Craigs list in the meanwhile.

 

Greetings

Hans

Edited March 27 by Tigweldor

[Digit]

The VFD I ordered has arrived and I hooked it up last weekend. I've left the original switch in the 3-phase circuit because on inspection it contained an overload protection circuit. I guess that when the motor does overload, the VFD would switch off earlier than the elements in the old switch have time to warm up, but having a backup protection doesn't hurt.

It took some looking though the manual to find the few things I needed to configure among a gazillion possible settings, but now that I have it configured it's simply a matter of turning the motor on with the green button on the VFD and turning the motor off with the red button. Added bonus is the configurable wind-down time: I've set it to three seconds so that the motor is actively stopped instead of it taking over a minute of free spin when it was powered directly from the mains.

I'll probably be adding easier-to-operate external start and stop buttons in the future and hide the VFD under the bench.

Added bonus: the motor has some mid-winding leads (so an auto-transformer actually) going to the junction box to offer 12V AC to power an auxiliary incandescent light, which still works.

@Tigweldor The VFD fan can be set to automatic, which means that it only runs when necessary, which apparently means from half a second after the motor is started to half a minute after the motor has been turned off. It doesn't bother me too much though; it makes about the same amount of noise as the motor itself and it will only be running for short amounts of time. I never have huge amounts of leather to skive.

[Tigweldor]

If you get a small  bridge rectifier, you can run a 12 Volt LED strip/lamp of your 12V AC motor output.

The 10 Amp model is more than enough.

They do not cost much - here just an example :

https://www.ebay.de/itm/196165851973

Greetings

Hans

 

Edited April 6 by AlZilla
Removed tracking

[Tigweldor]

@AlZilla ---- thanks for shortening the over long Ebay link  --- I usually do not like to post such links as the seller may delete the product and then the link is useless.

Same are my thoughts on uploading pics from a third party photo storage site - I have been on many a forum on other sites that only show a 404 when you click on a link/pic because the poster has deleted membership or his pics from that third party site.

 

Greetings

Hans

Edited April 6 by Tigweldor

[dikman]

If you simply rectify 12v ac to dc you will end up with something like 16v dc, just be sure your LED can run off more than 12v dc.

[Digit]

On 4/6/2025 at 5:08 AM, Tigweldor said:

If you get a small  bridge rectifier, you can run a 12 Volt LED strip/lamp of your 12V AC motor output.

I've got several of those lying around. One of them is currently powering a workplace heater (a Chinese Webasto clone) off a tranfsormer.

As long as the incandescent bulb keeps working I'll use that one. I'm not a fan of flickering LED lights (even with a cap on the rectifier they still flicker).