Wiring a VFD to a foot switch?

[Anonymous]

Dealing with the easy bit first it is possible to control a VFD using a foot switch. The precise details will depend on the footswitch and VFD input configuration. But there is no need to sweat over the details at this stage, as it can be done.

The much bigger problem comes in wanting to run a single phase motor from a VFD. Particularly as a 3 to 1 speed range is required. The short answer is that it isn't possible. However, something can be cobbled together for some specific types of single phase motor. If the motor is shaded pole or permanent split capacitor then it would be possible, albeit with poor performance.

So the next step is to identify if the existing motor is one of the two types listed above. From a practical point the motor is unlikely to be shaded pole as they are usually only available in limited power outputs due to their inefficiency.

Personally I wouldn't start from here as it will result in something that at best won't work properly and most likely won't work at all. Best thing is to beg, borrow or steal an appropriate 3-phase motor.

Andrew

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Well.now were getting to what I understand Andrew. In plain words I can understand not elecy jargon haha.

 

Ok now as.it goes the motor I have shown here is to show my idea will work for whay I need it to do and tat is profile.the tube.

 

So.next is to find a 3ph motor. And a VFD and foot control. Is there a certain type of 3ph motor to get. Is a dual phase motor ok ?

 

Also a foot.control..Will a sewing machine type.work ?

 

Thanks for the help .Andrew

Edited By wayne ollerenshaw on 13/01/2023 20:38:20

[peak4Participant @peak4]

Andrew, How did the engineer in the ATO video do it?
If you view the video on Youtube, they actually provide a link to the ones they sell specifically for the job; albeit in the US not here.

I've not bought one myself, either from ATO, or an AT2 knock-off/clone from China, though like you, I'd not start from there if I had a choice.
I've used an AT1 and other earlier ones with 3 phase motors in my own workshop, along with a ready built Newton Tesla package that came pre-fitted to my Warco 720 when I bought it.

Bill

[John HaineParticipant @johnhaine32865]

For heaven's sake! It only appears to be a 550w single phase induction motor. You could spend £00s on a VFD and YOU WONT BE ABLE TO CONTROL ITS SPEED. Much easier to go and buy an equivalent power servo sewing machine motor with controller and probably a foot switch which would cost about the same. Several threads on here about these.

[Les Jones 1Participant @lesjones1]

Re your post at 15:43 on the 13th. I am not clear if you are using the motor to drive a grinding wheel. If so 500 RPM seems too slow unless the grinding wheel is a very large diameter. A better description of what you are trying to do may give us the option to to suggest a solution to the original problem rather than your proposed solution of using a single phase motor with a VFD.

Les.

[Anonymous]

Posted by peak4 on 13/01/2023 21:36:31:

How did the engineer in the ATO video do it?

The video is rather short on technical detail, but it seems like all capacitors are disconnected and the start winding is used as a second 'phase'. We never actually see a motor running. It may well turn, but who knows what the torque/speed curve looks like. Start windings are generally for intermittent use so may not like being in circuit all the time. Just because something is available to buy doesn't mean that it actually works!

Andrew

[Anonymous]

Posted by wayne ollerenshaw on 13/01/2023 20:34:44:

Is there a certain type of 3ph motor to get. Is a dual phase motor ok ?

I'm not sure what a dual phase motor is? If you mean dual voltage then that will be fine. For the purposes of a test even a motor designed to run only on 415V will be fine. Running a motor intended for 415V on a VFD that outputs 240V will work, but just won't be able to produce full power.

As for a sewing machine foot pedal I don't know, it's all down to the details of the specific foot pedal. If it has switches then it should be possible to make them work.

Andrew

[jaCK HobsonParticipant @jackhobson50760]

Related but not applicable to OP…

I have a footswitch for a TIG welder which I also use on a VFD. Brilliant! I Recommend the bother of building a suitable connection box if you have a TIG footswitch.

[SillyOldDufferModerator @sillyoldduffer]

In simple terms for Wayne:

• There are several types of single-phase motor
• The more common types can't be speed controlled
• Some can be speed controlled, but power output is low and they get hot. Avoid
• A few types can be VFD controlled, but special wiring may be needed
• The type used in fans and electric drills can be speed controlled, but not with a VFD. They use a simple thyristor circuit to chop up the mains, which is OK up to a few hundred watts

The motor pictured doesn't look like the type that can be speed controlled: making the attempt has a high risk of failure, so high I wouldn't bother,

Note there are also at least three different types of electronic speed controller, each suitable for a particular type of motor, and that although all of them can be married to a foot-control, there is more than one type of foot-control. There are a lot of combinations, most of which won't work. To get a particular combination to work the motor, controller, and foot-control all have to compatible, and wired together correctly.

Much easier to by selecting all three major components to work together! Really tricky to get right when one doesn't quite know what's what.

I suggest buying a package, where someone else has done all the hard engineering and tested it. The motor/controller packages sold to power industrial sewing machines are popular. This 750W example is sold by Amazon, £178. Many other motor powers, prices and vendors available.

Dave

[Clive Brown 1Participant @clivebrown1]

There's a caveat here. The OP seems to suggest that he's intending this set-up to drive a grinding wheel. In general, it's not good practice to use variable speed motors as a drive. For obvious reasons, a grinding wheel is subject to strict over-speed limitation. A variable speed drive system won't necessarily comply. Some types of motor are capable of very high speed. Care is needed.

Edited By Clive Brown 1 on 14/01/2023 11:40:36

[noel shelleyParticipant @noelshelley55608]

This is all becoming far to dangerous ! The OP has little or no understanding of electrical terms, centrifugal force or grinding. My advice to the OP is either buy a machine that will do what he needs – or forget the idea ! Noel.

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Thanks Andrew and Old.Duffer..Good help there. I will.research more on the Web and stop meithering you over this.

For those that dont get what I am.doing please.read.my laat.post on page 1.

I have a tube on the motor spindle holding a n inner tube so I can grind/profile then end.

[Ian PParticipant @ianp]

I will stick my neck out first.

Wayne, I have read all your posts in this thread and admit I still do not understand what you are trying to do!

You mention 'grinder'. Is that an angle grinder, bench grinder, surface grinder, die grinder or something else?

Thick wall and tube (two tubes even) mean little without knowing the context.

Lots here who are more than willing to help but its difficult by guesswork.

Ian P

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Posted by Ian P on 14/01/2023 13:27:09:

I will stick my neck out first.

Wayne, I have read all your posts in this thread and admit I still do not understand what you are trying to do!

You mention 'grinder'. Is that an angle grinder, bench grinder, surface grinder, die grinder or something else?

Thick wall and tube (two tubes even) mean little without knowing the context.

Lots here who are more than willing to help but its difficult by guesswork.

Ian P

I usually take pictures but there is no way to do thay from my phone camera.

Ok

Imagine the motor with a tube on the spindle

Now imagine a tube inside the tube which is locked into it.then an angle.grinder is used to radius the end of the inner tube

The inner tube is removed once the end has been radiused.

Then another tube in inserted etc etc and again and again.

Not sure what it has to do with the foot control.and VFD I am.trying to worknon and see if it's possible.

Hope thay helps out folk to help out the foot control and VFD.

[Ian PParticipant @ianp]

Well if you are not sure what foot control and VFD have to do with this thread, I'm not sure anyone else can tell you!

See the first sentence of your original question

Ian P

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Posted by Ian P on 14/01/2023 19:12:22:

Well if you are not sure what foot control and VFD have to do with this thread, I'm not sure anyone else can tell you!

See the first sentence of your original question

Ian P

I Can't see what it matters on the end of the motor spindle to do with having a VFD fitted with foot control.

Folk have gone off topic asking things that they are assuming.

All.i asked in the first place was if I can fit a foot comtroll.with a VFD to run a motor.

[Les Jones 1Participant @lesjones1]

The answer to that question is probably yes. For a definite answer we would need to see the manual on the VFD. When you get a definite answer to that question you would probable then need to ask us how to connect it. The main concern we all have is that the VFD may not work well enough with a single phase motor.

Les.

[duncan webster 1Participant @duncanwebster1]

Trying to use a motor as a sort of a lathe, with the outer tube as a rough sort of a chuck? All sounds a bit iffy to me. Quick way to get to the front of the queue at A&E is to mention angle grinder.

[Harry WilkesParticipant @harrywilkes58467]

Posted by duncan webster on 14/01/2023 20:43:57:

Trying to use a motor as a sort of a lathe, with the outer tube as a rough sort of a chuck? All sounds a bit iffy to me. Quick way to get to the front of the queue at A&E is to mention angle grinder.

H

[wayne ollerenshawParticipant @wayneollerenshaw89933]

Posted by duncan webster on 14/01/2023 20:43:57:

Trying to use a motor as a sort of a lathe, with the outer tube as a rough sort of a chuck? All sounds a bit iffy to me. Quick way to get to the front of the queue at A&E is to mention angle grinder.

I guess your one of them folk. As your unable to do it nobody else can.

[Author]

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