1984 Easymill spindle motor, 440 volts only or dual voltage?

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ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

1984 Easymill spindle motor, 440 volts only or dual voltage?

Post by ClitheroeKate » Sun 17 Nov , 2013 23:38 pm

Is the spindle motor off my 1984 Easimill suitable for connection in delta and running off 220 volts through a vfd?

As can be seen in the photos, the name plate shows it as being 440 volts 3 phase with no mention of 220 volts. Before I took the motor off the machine there were no brass/copper straps between the U, V and W connections seen when connecting the motor in star and running off 440 volts. Another reason I'm not sure is that there is no mention of star or delta on the name plate either though there are the six terminals, labled as U, V and W as is usual with a dual voltage motor.

I've searched the net and not found anything to tell me what the connections are in a single voltage 3 phase motor, so any help would be appreciated.
Attachments
photo-1-1.jpg
Motor internal connections.
photo-1-1.jpg (893.55 KiB) Viewed 6594 times
photo-2-1.jpg
Motor connections before the motor was disconnected
photo-2-1.jpg (1003.92 KiB) Viewed 6594 times
file.jpeg
Motor name plate showing 440 volts only.
file.jpeg (183.16 KiB) Viewed 6594 times

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Mon 18 Nov , 2013 16:53 pm

All six connections to the windings have been brought out, so it should be possible to wire the motor in star or delta.

Star connection:- power to U1, V1, W1, Link U2,V2,W2.
Delta connection:- Link U1 & V2, V1 & W2, W1 & U2. power to U1, V1, W1.

However it doesn't appear to be a dual voltage motor with each winding split in two, resulting in 9 or 12 connections.

ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by ClitheroeKate » Mon 18 Nov , 2013 17:07 pm

Thanks very much for your reply.
I'll give it a try.

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Mon 18 Nov , 2013 17:20 pm

Looking at the plate, it seems to be a two speed motor where the speed depends on whether the motor is connected in star or delta.

For some reason the straps for delta connection don't appear to be shown.

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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by angel-tech » Mon 18 Nov , 2013 17:49 pm

is there an inverter already on the easymill driving the motor ?

ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by ClitheroeKate » Mon 18 Nov , 2013 22:58 pm

No, there is no inverter. The machine is belt driven, 3 phase 440 volts to the spindle and coolant motors with 24 volts to the cnc box. When I saw the machine running before I bought it it was running from a 3 phase supply.

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Tue 19 Nov , 2013 1:52 am

Looking at the wiring diagram for the Easymill, it uses external star/delta switching for the spindle motor. This enables the high and low speed ranges to be selected. That accounts for there being six wires going to the motor rather than three and no brass straps.

As you say though, no inverter.

ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by ClitheroeKate » Tue 19 Nov , 2013 8:08 am

So am I right with the following?

A) The motor will run 1430 rpm when connected to 440 volts in star.

B) It will run at 710 rpm when connected to 440 volts in delta.

C) It won't run usefully, if at all from 220 volts when connected in either star or delta through a VFD.

If I'm right with C) what can I do? The research I have done tells me the mounting plate is totally non-standard and though the machine still is still produced in Taiwan, my attempts to source a new motor through the UK importers (http://www.chestermachinetools.com/830v ... 3989-p.asp) have been un-successful (not to mention what the cost might be)

I've been quoted silly money to have the motor re-wound so the only another option I can see is to replace the mounting plate on a new dual voltage motor with a specially produced item to allow it to mount to the milling machine.

Or is there some-thing else I can do to?

Edit.
After posting this I've noticed Vandal has replied to a question I asked in this post viewtopic.php?f=34&t=4093&p=17274#p17274 He's going to check his motor and let us know what he finds. The questions above still stand.

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Tue 19 Nov , 2013 12:17 pm

I'm afraid I cannot fully answer your question.

The electrical wiring diagram for the Easymill can be downloaded here:-

viewtopic.php?f=34&t=3420

Looking at sheet 2.

When HIGH speed is selected contactors C1 and C2 are operated connecting the motor in delta.

When LOW speed is selected only contactor C3 is operated. This contacts the phases to U1, V1 and W1, there being no connection to U2, V2 and V3. I cannot see how this will make the motor run unless the motor has internal connections which are not shown. These connections do match those shown on the maker's plate on the motor though. They also appear to match the slip speeds to be expected from 4 and 8 pole motors.

Without knowing the internal connections of the motor I cannot tell you whether is can be powered from a VFD.

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Tue 19 Nov , 2013 12:31 pm

The motor appears to be switchable between 4 and 8 poles, something I've not come across before. Internal and external wiring is probably as shown in this link:-

http://www.elprom-gem.com/en/specials/t ... motors.pdf.

The lower set of diagrams are applicable to 4/8 pole motors.

Looking here, a dual pole/dual pole motor cannot be used with an inverter (VFD).

http://www.powercaps.co.uk/wp-content/u ... -Guide.pdf.

It looks like you'll have to use a rotary or static convertor if you want to retain the two speed function,

To use a VFD you'll need to fit a dual voltage motor, which will enable you to vary the motor speed.

ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by ClitheroeKate » Tue 19 Nov , 2013 12:56 pm

Thanks very much for your help with this, I appreciate your knowledge and input.

It looks like I'm forced down the route you suggest, I'll go through the info you've supplied later when I get home and we'll see what Vandal says when he's had chance to have a look at his motor. I rather suspect that his is dual voltage though.

Is it a sensible thing to do to try connecting it to the VFD in delta? What would happen if it was wrong?

MAX THE MILLER
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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by MAX THE MILLER » Tue 19 Nov , 2013 13:07 pm

By all means try it, but remember that because of the way this motor is wired internally you'll need to connect the phase wires from your VFD to U1, V1 and W1 with no straps.

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Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by Andy B » Tue 19 Nov , 2013 14:00 pm

I don't see why an inverter shouldn't be used with this motor - as long as it has 415V output.
Generally 240V in, 415V out inverters are a lot more expensive than 240/240.
But as you only have a 1hp motor, the one here looks quite reasonable:
http://www.invertersdirect.co.uk/Produc ... MILL-DRILL

If in doubt, send a mail to Drives Direct with your motor photos and ask them.

I have no connections with this company, nor experience of their products.
Andy

ClitheroeKate
Posts: 19
Joined: Sat 23 Mar , 2013 22:11 pm
Hardware/Software: Denford Easymill 3, 1984, i believe it is totaly origonal. The spindle motor is marked as 1 hp, 3 phase with four pulleys for speed changes. 3 phase coolant pump. 1 board in the control is marked as PNC3. There are a few buttons missing on the control box and the tape drive dosen't work. The previous owner ran it off 3 phase and as I haven't got three phase at home I'm looking to convert it to single phase and up-date/up-grade it in the process. I am however a complete newbie.

Re: 1984 Easymill spindle motor, 440 volts only or dual volt

Post by ClitheroeKate » Wed 05 Mar , 2014 9:00 am

Thanks to all for your replies.

I put this project down for a bit as I've been trying to get hold of a small lathe (manual) for my shed and having got one I've been setting it up (Its quicker for me to get the lathe up and running than the Easimill with my knowledge).

I got a 2hp dual voltage 3 phase motor off an Easiturn for a reasonable sum and this runs fine on the bench from the 2hp VFD I had already.

So I drew up a new base plate to convert the Easiturn motor to fit on the Easimill, got a burn out made up and have so far turned it up on the lathe. A video of the turning in progress is at the link below. The two motors are shown towards the end of the video while the drawings are shown just after the start.

https://www.youtube.com/watch?v=tGnrSxekvAA

Andy.

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