Colchester Bantum, keep 3 phase or go single?

[James 1433]

Hi everyone. New to this forum. Im a Cnc turner by trade but have just brought a Colchester Bantum for home use (mainly for making motorcycle parts on). Its a Mk1 with the 2 speed 3 phase motor. Im wondering how best to run it, either with an inverter or switching to a single phase motor. Thanks.
Here's some pic's, got it for £250 bargian i think.

[Al_The_Man]

Probabally not alot of difference in cost going VFD, you will also be able to vary the rpm if need be.
Al.

[mactec54]

Hi James 1433

Go with the VFD it is better than going to single phase, its a shame people don't care for these machines better, but it will clean up & look like new again, I rebuilt a Chipmaster 15 years ago, it was worse than your one, & it has traveled around the world with me, it's in use almost every day & you can still hold .0001 on it, I never repainted mine just cut & polished it I will post a photo of it

[BillTodd]

Keep the dual speed motor and use a VFD.

You'll probably find the motor is 440v only (it'll have six wires for a single voltage dual speed), so you will need a step-up transformer to run it from 230vac (you use a 415/440v 3ph input VFD but with a 1ph input)

A 1KVA step-up transformer from Airlink will set you back about £60. The plus side however, is that 1 or 2hp 440v VFDs can be found on ebay fairly cheaply (I picked up a couple for £25 each).

There are diagrams of my slightly complicated HLV-H conversion here
http://www.mycncuk.com/forums/showth...=2628#post2628

[James 1433]

Thanks for the replys everyone. Im not to good with electronics but iv got a sparkie mate who will understand all this better. I found a Vfd on ebay, is it what i need? http://cgi.ebay.co.uk/ABB-3phase-mot...d=p3286.c0.m14
Also the terminals on my motor are Low speed A3 C3 B3
High speed A2 B2 C2 and on the plate it says 380/ 420 volts.

Thanks Again. James.

[Al_The_Man]

You should ask the lister and/or consult the manual if possible as to whether it will accept 1 phase input, if so, is there is any de-rating for 1 phase.
Al.

[mactec54]

Hi James 1433

That drive is only for 1HP??? I think your machine has more than 1HP, your drive needs to be bigger or as big as the motor on your machine this depends on how it is set up your power supply Etc

[BillTodd]

Originally Posted by Al_The_Man You should ask the lister and/or consult the manual if possible as to whether it will accept 1 phase input, if so, is there is any de-rating for 1 phase. Al.

Yes, good point Al. The Siemens MM150s that I used were good on both counts, but it's worth checking with the manufacturer.

[BillTodd]

Originally Posted by James 1433 Thanks for the replys everyone. Im not to good with electronics but iv got a sparkie mate who will understand all this better. I found a Vfd on ebay, is it what i need? http://cgi.ebay.co.uk/ABB-3phase-mot...d=p3286.c0.m14 Also the terminals on my motor are Low speed A3 C3 B3 High speed A2 B2 C2 and on the plate it says 380/ 420 volts. Thanks Again. James.

That's the sort of thing James but £80 for a 1hp drive isn't the cheapest I've seen. If you can, get a 2hp (1.5kw) for a 1hp motor, so it can run under-rated as per the above post.


[edit]
http://cgi.ebay.co.uk/Imo-Jaguar-Inv...d=p3286.c0.m14

http://cgi.ebay.co.uk/Siemens-Microm...d=p3286.c0.m14
This is actually a 1.5kw drive (basically, the same model I used)