Mill motor change

[Andy SprouleParticipant @andysproule22368]

Hi,has anyone ever changed the motor on this type of mill?Sorry for wonky pic.Thinking of changing this from three phase to single.

[Andy SprouleParticipant @andysproule22368]

[mick70Participant @mick70]

can you not just get inverter?

that's what i did with couple of three phase motors i got from work.

[John RuddParticipant @johnrudd16576]

If there is a flange faced mount, single phase motor available to drop in, replacement ought to be straight forward. You may need to tweak the control switch gear?

If such a motor isnt readily available, you could, if you know the frame size, obtain a single phase in the appropriate size, and swap the rotor/stator assemblies if you are confident and have the desire, just retain the original case and end flange…..

[Andy SprouleParticipant @andysproule22368]

Can't use a Vfd motor not suitable.I didn't know that it was possible to swap rotor/stator assembly.Here is a pic of mounting.

[Martin ConnellyParticipant @martinconnelly55370]

Why is the motor not suitable for a VFD? Have you tried one on it?

Martin

[not done it yetParticipant @notdoneityet]

Not a clue as to what mill or motor it is. 415V three phase? 220V three phase? Is it a dual voltage motor? How many horese power (or kW)? What type of starter?

[Andy SprouleParticipant @andysproule22368]

Mill is a Gate progress RF 45.Motor plate

[John Stevenson 1Participant @johnstevenson1]

Two speed motor so no you can't use an inverter.

What you can do is get a rewind company to just connect it in delta, use one winding and fit the VFD then you can over speed it if needed on the VFD.

Reason I say get a rewind company to do this is they can do this with their eyes shut but if like most motors it has a connection diagram inside the terminal box post that here and someone will be able to help

Fitting a single phase motor will work but you are then limited to single speed, a VFD will give you variable speed and be much smoother for about the same price.

Where in the UK are you ?

[Andy SprouleParticipant @andysproule22368]

Hi John,I was told by a company that supply Vfds because it is a 2 speed and 415 volt only motor that it couldn't be run by a Vfd.Are you positive this can be done?

[John Stevenson 1Participant @johnstevenson1]

Pretty certain, I do a lot of work for the rewind people and I'll ask the question.

Again where in the UK are you ?

[Andy SprouleParticipant @andysproule22368]

I am based in the North of Ireland.John if this can be done it would save me so much hassle.

[John Stevenson 1Participant @johnstevenson1]

Can you take the cover off the terminal box on the motor and see if there is a wiring diagram inside, often etched on the inside cover, or failing that a shot or two of the terminal block.

[Andy SprouleParticipant @andysproule22368]

Pics of inside cover which is lying on its left side and pic of wiring.

[Martin ConnellyParticipant @martinconnelly55370]

Andy, I would suggest talking to a VFD supplier and giving them details of the motor. They may have the solution.

Martin

[Andy SprouleParticipant @andysproule22368]

John a clearer pic of wiring.

[Johnboy25Participant @johnboy25]

I suggest you just treat it as a two pole motor connected in delta (also referred to as mesh) then use a VFD inverter. That will give you a max motor speed of 1420 rpm.

John

Edited By Johnboy25 on 25/09/2016 20:49:08

[Andy SprouleParticipant @andysproule22368]

Johnboy,can you explain how I do that?

[john fletcher 1Participant @johnfletcher1]

Hello Andy I think you should take the motor to a rewind shop and ask for their opinion and help. The motor is not a run of the mill motor. I think it will have a total of 6 connection which must be configured in the correct manner to ensure NO burner out. If you connect in Delta the 415 volt windings will, via an inverter receive 240 volts. Apparently there are modified inverters which do give out 415 volts. There was a discussion on Home workshop some time ago about modifying inverters apparently its a simple connection. Never need to try it out and haven't got a spare inverter to play with. Anyway,how is your Naerok ? John

[John Stevenson 1Participant @johnstevenson1]

Ok Andy already knows this as we spoke by PM but for the others this is the information.

This motors is a modern 2 speed motor in that there is only one winding [ 3 actually, one for each phase ] with tappings that can be configured to give two speed.

The older two speed motors used to have two switchable independent windings.

So these new ones cannot be wired to 220 v for a single phase inverter. and for some reason, not explained they don't like a 440v in 440v out unit either.

[Ian PParticipant @ianp]

If each of the three windings are tapped then why are only six terminal visible? I would have expected to see 3 x 3 so 9 separate connections.

Tappings in a winding are usually there for voltage selection so I dont understand how the motor can be wired for 2 or 4 pole operation. Do you have a link to information on this type of motor.

Ian P

[John RuddParticipant @johnrudd16576]

Andy,

If you prefer going the single phase route, then I think this is your machine and they ought to be able to help….

http://www.gatemachinery.com/product/pr-4md

It also looks very similar to this one from Chester…..

http://www.chesterhobbystore.com/lux-milling-machine-3996-p.asp

So obtaining a 1 ph motor isnt impossible and is probably easier than sorting your current one with an inverter…

Just my 2penneth…..

Edited By John Rudd on 27/09/2016 14:44:00

[Andy SprouleParticipant @andysproule22368]

Thank you all for replies.Different motor needed.

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