Electric motors

This topic has 9 replies, 7 voices, and was last updated 7 April 2021 at 07:22 by Stephen Middleton.

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6 April 2021 at 10:27 #538315
Stephen Middleton
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@stephenmiddleton53822
Hello, I have recently acquired a wolf jahn jig borer and a chronos wheel cutting engine, unfortunately neither has a electric motor. I would be obliged if anyone has any idea which type and brand of motor would be suitable keeping in mind that I would prefer a simple on/off switch rather than a foot switch.

Thanks, Steve.
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6 April 2021 at 10:27 #14217
Stephen Middleton
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@stephenmiddleton53822
6 April 2021 at 10:42 #538318
Hollowpoint
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@hollowpoint
Your choice of motors is almost endless. You probably just want something reasonably small say 100 to 300w AC

Brand wise I don't really think it matters. Parvalux make good small motors. But I think even a Chinese machine mart special would be fine.
6 April 2021 at 11:17 #538325
John Haine
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@johnhaine32865
Nice machines. My recommendation would be small 3-phase induction motors with variable frequency drive; or single-phase but they would be fixed speed.

An excellent UK motor supplier is Parvalux – I have one of these on my Quorn (single phase) and a 3 phase on a Unimat:

Photo shows motor and drive. The drive is available from Newton Tesla who give excellent support. This would be the right sort of motor for both your applications. Not the cheapest but very nice for some nice machines.
6 April 2021 at 11:20 #538327
Emgee
Participant
@emgee
Stephen

You may need a 2800 rpm motor on the jig borer to get speeds suitable for small cutters, .37kW output minimum.

For the wheel cutting engine perhaps a 1450 rpm motor will suffice, as suggested 300W output.

Emgee
6 April 2021 at 13:03 #538343
John Haine
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@johnhaine32865
The motor shown is 2800 rpm, it has between 1:2 and 2:1 on the pulleys and will happily run on the inverter up to 100 Hz so if I want I can run the spindle stupidly fast!
6 April 2021 at 13:29 #538349
Clive Steer
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@clivesteer55943
Stephen

Check out the recent thread regarding Brushless DC motor for mini lathe in the General section as this suggests the use of a Sewing machine motor and speed controller the comes as a complete plug&play package at a very reasonable price.

Clive
6 April 2021 at 13:44 #538350
Ian P
Participant
@ianp
By far the best method is as John Haine suggests (although I would hide the VFD and have pot and switch in convenient location).

If the spindle drive is via a belt anyway then using a 'too powerful' motor does not matter. The cutter will only take what power it needs as the drive system incorporates the 'fuse'/ slipping clutch.

As may others have said before, you wont regret going three phase and VFD!

For watch/clock making machines relatively low power is needed, traditionally universal motors were the norm and still nothing wrong with them. They are probably quieter and have much less vibration than a single phase induction motor but a three phase motor would be my choice.

If your machines are staying in their own places on the bench then one motor could (via belts/countershafts) drive both of them, less convenient if you need to move them around or store them after use.

Ian P
6 April 2021 at 18:51 #538400
Robert Atkinson 2
Participant
@robertatkinson2
Posted by John Haine on 06/04/2021 11:17:01:

Nice machines. My recommendation would be small 3-phase induction motors with variable frequency drive; or single-phase but they would be fixed speed.

An excellent UK motor supplier is Parvalux – I have one of these on my Quorn (single phase) and a 3 phase on a Unimat:

Photo shows motor and drive. The drive is available from Newton Tesla who give excellent support. This would be the right sort of motor for both your applications. Not the cheapest but very nice for some nice machines.

Hi John,
Nice lathe, but unfortunatly the inverter installation is very poor and potentlly dangerous.
1/ No strain relif on the power leads.
2/ One lead has its ground lead unter tension. If the lead is pulled this could come off. If the motor earth comes off with it it could possibly touch the live terminal next to it and making the motor case live even if not running.
3/ Mounting is wrong. The front panel and thus channels through the heatsink, should be vertical for proper convection cooling.
4/ You appear to be using the front panel controls for normal operation. They are only intended for initial set-up and maintenence.
5/ The drive should be in an enclosure.

1/ & 2/ are the most important and should be addressed. The heatsink is probably common to higher rated models and is probably OK at the power and duty cycle you are running.
As a minimum you should really have an external emergency stop rather than relying on the front panel controls.

If it is a personal item with no one else able to access it then the condition is purely your concern. But you have posted pictures that others may copy so I feel obliged to point out the issues so they do not take it as an acceptable example of VFD installation. Nothing personal.

Robert G8RPI.

Edited By Robert Atkinson 2 on 06/04/2021 18:53:33
7 April 2021 at 07:22 #538468
Stephen Middleton
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@stephenmiddleton53822
Hello, thanks everyone for your ideas and quick response. I now have enough information as to which way to go. Unfortunately space is at a premium and I will have to make the set up portable. As always plenty of knowledge amongst forum members.

Regards, Steve.
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