bhk
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Post by bhk on Sept 15, 2014 6:57:14 GMT
Big day here in NZ I've finally put money down for a lathe and now awaiting its delivery! Some of you know through emails I've been looking for a while wanting to get a decent machine at the right price. Along came a Colchester Bantam mk1 Condor, ex polytechnic machine which has hardly any work. Full set of change gears, 4 jaw, 3 jaw faceplate. The only thing it is missing is a steady. It's is currently fitted with a 2 speed 3 phase motor, not having 3 phase I will have to do one of the following: change to single phase and lose reverse, replace with a standard 3 phase motor and run through an inverter. Bite the bullet and buy a rotary phase converter. www.scottmachinery.co.nz/used.php?s=480&ss=880&scode=LCNT-1-1600Cheers Sean |
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Post by ejparrott on Sept 15, 2014 8:02:02 GMT
Don't change to single phase, my Colchester was single phase when I got it, luckily it came with the original motor which I refitted. Took forever to get up to top speed, and was really noisy when it was running.
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uuu
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Post by uuu on Sept 15, 2014 8:03:23 GMT
Very nice. You can get some inverters that step up to the higher voltage. Would they run the existing motor?
Wilf
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bhk
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Post by bhk on Sept 15, 2014 8:53:27 GMT
Hi Wilf,
Until I get the machine home I'm not sure, but from reading yes I think a step up inverter is what would be needed for the existing motor.
Cheers
Sean
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Post by Deleted on Sept 15, 2014 10:04:27 GMT
Hi matey !!-------------I'm Great Western Green with envy --Ha-ha !!....... I like those Bantams for the same reasons that Tech. Colleges bought them for in the first place......... 3MT up the main spout and 2MT in the tailstock gives a good range of tool holding.........In days gone by it used to be the thing for the average Model Engineer to change to a single phase motor but I agree with "young" Mr Parrot-------------- Happy machining !! EDIT}---- One thing I do remember as an Apprentice is standing next to my Instructor when he used the foot-brake !!!!----------- I didn't do that again, I can tell you !!
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steam4ian
Elder Statesman
One good turn deserves another
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Post by steam4ian on Sept 15, 2014 10:22:13 GMT
Sean
You should be able to reconnect that 3 phase motor to operate on 240V instead of 415V. It can then be operated by an variable speed inverter fed directly from 240V single phase without a special and expensive step up inverter. I am not sure as a professional EE I have seen a step up inverter in the usual trade catalogues and this is my line of business. A standard 240V single phase to 240V 3 phase inverter will cost about AUD250, try the Baldor range; mine was branded Delta and procured from Royce Cross Agencies.
The reconnection of the motor should be able to be done in the terminal box, you reconnect from star to delta.
If you have any doubt as to what to do get a licensed electrician to do it for you.
Regards
Ian
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Post by ejparrott on Sept 15, 2014 11:38:49 GMT
... I like those Bantams for the same reasons that Tech. Colleges bought them for in the first place......... 3MT up the main spout and 2MT in the tailstock gives a good range of tool holding...... Is that all? I thought Colchesters of that size all had special spindles that needed an adaptor to take a 4MT, and 3MT in the tailstock? |
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isc
Statesman
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Post by isc on Sept 15, 2014 12:27:36 GMT
Sean, Scotts should be able to help with a power supply. isc
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bhk
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Post by bhk on Sept 15, 2014 18:11:01 GMT
... I like those Bantams for the same reasons that Tech. Colleges bought them for in the first place......... 3MT up the main spout and 2MT in the tailstock gives a good range of tool holding...... Is that all? I thought Colchesters of that size all had special spindles that needed an adaptor to take a 4MT, and 3MT in the tailstock? Ed is correct, 4MT and 3MT, one thing which drew me to the Bantam is that they are scaled down industrial machine, I've operated one in the past and was might impressed by it capacity. |
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bhk
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Post by bhk on Sept 15, 2014 18:47:54 GMT
Sean You should be able to reconnect that 3 phase motor to operate on 240V instead of 415V. It can then be operated by an variable speed inverter fed directly from 240V single phase without a special and expensive step up inverter. I am not sure as a professional EE I have seen a step up inverter in the usual trade catalogues and this is my line of business. A standard 240V single phase to 240V 3 phase inverter will cost about AUD250, try the Baldor range; mine was branded Delta and procured from Royce Cross Agencies. The reconnection of the motor should be able to be done in the terminal box, you reconnect from star to delta. If you have any doubt as to what to do get a licensed electrician to do it for you. Regards Ian Hi Ian, Thanks for that, once I get the machine I'll upload more pictures and try figure out what is going on in the terminal box. I do hope that it can be done, as the step up inverters are expensive, hence it would cheaper for a new motor and converter. Luckily I do have a friend that is an electrician so he should be able to sort me out once I get going. Cheers Sean |
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Post by Deleted on Sept 15, 2014 20:41:42 GMT
Beg your pardon chaps, my mistake.---------I've just re-read the Specs. and yes,it's a 3MT in the tailstock >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Specifications
Model Bantum 1600 Mark 1
Swing over bed 286mm
Swing over cross slide 178mm
Distance between centres 508mm
Spindle bore 25mm
Spindle speeds 36 - 1600 rpm 16 steps
Tailstock taper 3MT
Thread cutting Metric and imperial
Main motor 2HP
Power supply 415 volts / 50 hz / 3 phase
Freighting details (L x D x H) 1400mm x 800mm x 1500mm
Weight (approx) 500 kg
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bhk
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Post by bhk on Sept 15, 2014 21:37:38 GMT
I have had Scott's send me some more pictures of the motor and its info plate.   |
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uuu
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Post by uuu on Sept 16, 2014 6:24:32 GMT
So, as suspected, it's not a straight fit of a standard inverter.
You might find a genius who can find and split the star points (I'm supposing more than one on this two speed motor).
Or you're back to some of the options already noted.
Wilf
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Post by fostergp6nhp on Sept 16, 2014 6:33:40 GMT
It might be worth contacting the motor manufacturer to ask their advice if it is feasible to reconfigure the winding connections to allow 220v phase to phase operation, possibly still with the 2 speed potential.
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Post by Roger on Sept 16, 2014 6:52:36 GMT
It all depends on whether the star point is buried deep in the windings, I suspect it is. Still, motors are cheap enough and at least you know exactly what's in there. I'd take that information to your local electrical wholesaler and see what they can offer you. Here's their global contacts page if you want to ask the manufacturer about it. |
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bhk
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Post by bhk on Sept 16, 2014 8:14:28 GMT
Email sent.
See what if anything comes back
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Deeja
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Post by Deeja on Sept 16, 2014 10:59:28 GMT
I have a Bantam - very good lathe. Has 2 speed 3 phase motor. I just got the local electricity supplier to put 3 phase to the house. Easy to do and cost not too much. Looked at 1 phase motor, inverter etc and decided 3-ph was the easiest and simplest. Once 3-ph is connected no other ongoing costs.
Consider getting 3ph instead of all the half baked options.
Deeja
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Post by ejparrott on Sept 16, 2014 11:35:55 GMT
Must be different on your side of the world, mega bucks to have 3-phase installed to a home in the UK!
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dfh
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Post by dfh on Sept 16, 2014 11:51:07 GMT
I have a Bantam - very good lathe. Has 2 speed 3 phase motor. I just got the local electricity supplier to put 3 phase to the house. Easy to do and cost not too much. Looked at 1 phase motor, inverter etc and decided 3-ph was the easiest and simplest. Once 3-ph is connected no other ongoing costs. Consider getting 3ph instead of all the half baked options. Deeja Unless you have a 3ph cable already run close to the house, as in my case it is a single core cable, would mean drive to be dug, road to be dug until some point to connect to 3 phases which is about 75yds away, possibly garage floor as well, so not that easy or cheap, especially as would have to cross a busy road to get to the grass verge down the middle, been there, priced it up and decided to use 1ph equipment. David |
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Post by Roger on Sept 16, 2014 11:56:22 GMT
I have a Bantam - very good lathe. Has 2 speed 3 phase motor. I just got the local electricity supplier to put 3 phase to the house. Easy to do and cost not too much. Looked at 1 phase motor, inverter etc and decided 3-ph was the easiest and simplest. Once 3-ph is connected no other ongoing costs. Consider getting 3ph instead of all the half baked options. Deeja Sorry, but a full variable speed drive option isn't 'half baked' it's the king of options. If you've not used a variable speed drive on a lathe, you don't know what you're missing. |
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