By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

Good morning

Intro

All Topics | Latest Posts

Search for:  in Thread Title in  
Tom Walker 112/08/2020 06:23:29
45 forum posts
6 photos

Hallo I have just joined, as I now have more time being semi retired. So now I want to get stuck in to more fettling. (So does my missus!).

I am a vintage car/bike enthusiast, living in Leicestershire UK. I have set up a small machine shop in my workshop, and have been a keen reader of the ME website for many years.

I have just bought a nice Colchester Bantam lathe (square head, not sure which MK) which came with an inverter. I have 3 phase, so re-connected the motor, and it works very nicely.

But I would like to get it running with the 2 speed motor. So I need to find someone who has one, and hopefully the necessary switch gear to make the change.

Also any advice gratefully received.

Thanks, Tom.

Brian H12/08/2020 08:18:27
avatar
1742 forum posts
112 photos

Hello Tom and welcome. Can't help with the lathe I'm afraid but I'm sure someone who can will be along shortly

Brian

Howard Lewis12/08/2020 09:01:25
3536 forum posts
2 photos

Welcome!

When things approach normal, if ever, do join a local Model Engineering Club, to socialise and get face to face help when it is needed.

Lots of experience on here, so lots of advice, should you need it, waiting in the wings.

Howard

Chris Evans 612/08/2020 09:33:09
avatar
1725 forum posts

Welcome along Tom. Does your lathe still have the original two speed motor ? Some Bantams I have seen are fitted with a single speed motor and VFD inverter.

Chris. ( another vintage bike guy)

Thomas Cooksley12/08/2020 12:18:15
32 forum posts

Hi Tom, Welcome to the forum. from another Tom.

Howard Lewis12/08/2020 15:58:35
3536 forum posts
2 photos

Welcome!

A lathe is a most useful tool.

Now can you will able to do all sorts of jobs.

Beware the neighbour "Got a little job for you, shouldn't take long. Can you just..... )!

At least you stand a good chance of repairing something that breaks at 7:00 o'clock on a Saturday night, and is in constant use or need.

Go for it!

Howard

Tom Walker 112/08/2020 18:03:19
45 forum posts
6 photos
Posted by Chris Evans 6 on 12/08/2020 09:33:09:

Welcome along Tom. Does your lathe still have the original two speed motor ? Some Bantams I have seen are fitted with a single speed motor and VFD inverter.

Chris. ( another vintage bike guy)

Thanks for all the welcomes.

Chris, I have taken off the VFD inverter and re-arranged the cables to supply the motor with my 3 phase.

I dont actually know if its a 2 speed motor or not, I need to look at the plate. But the switch would be a give-away surely?

The lathe would be a better machine with a 2 speed motor, and seeing as most people with 2 speed Bantams want to convert to single phase, which means ditching the 2 speed motor, I was hoping someone would have one under their bench.

As you can see, I am an optimist!

Steviegtr12/08/2020 19:34:35
avatar
1370 forum posts
143 photos

Not sure why you would take off the inverter, when that would have given you any speed you wanted. Oh & welcome to the Forum.

Steve.

Jon Lawes12/08/2020 19:43:24
avatar
388 forum posts
Posted by Steviegtr on 12/08/2020 19:34:35:

Not sure why you would take off the inverter, when that would have given you any speed you wanted. Oh & welcome to the Forum.

Steve.

You assume it was a variable inverter.

Steviegtr12/08/2020 22:59:37
avatar
1370 forum posts
143 photos
Posted by Jon Lawes on 12/08/2020 19:43:24:
Posted by Steviegtr on 12/08/2020 19:34:35:

Not sure why you would take off the inverter, when that would have given you any speed you wanted. Oh & welcome to the Forum.

Steve.

You assume it was a variable inverter.

Yes. I know there are some transverters that are not. But most inverters that i have come across are variable. Wait for op to respond maybe.

Steve.

Andrew Johnston13/08/2020 09:53:45
avatar
5635 forum posts
652 photos
Posted by Steviegtr on 12/08/2020 19:34:35:

Not sure why you would take off the inverter, when that would have given you any speed you wanted.

Probably because the OP has 3-phase available and if he wants to run his industrial machine to capacity he'll be better off using the motor as designed rarther than an inverter. Power is more important than infinitely variable speed.

Oh, and welcome to the forum Tom. thumbs up

If the lathe has a 2-speed motor I assume there must be an electrical switch somewhere on the controls for low and high ranges? Both of my machines that have 2-speed motors have these switches, two in the case of the horizontal mill.

Andrew

Emgee13/08/2020 10:06:37
1650 forum posts
224 photos

As Andrew says the Bantam 2 speed motor is controlled by a 2 speed switch/contactor arrangement, 800rpm spindle speed in low range with max 1600 in high range. Full wiring details in the manual.
From memory there are 6 selectable speeds by lever in each of the ranges, lowest being 32rpm in the 800rpm range.

Tom

If you want copy of the manual send me a PM (click on Message Member at bottom of message) with your email address and I can send you a copy.

Emgee

Edited By Emgee on 13/08/2020 10:11:53

Simon Williams 313/08/2020 10:20:06
519 forum posts
80 photos

Good morning Tom, welcome to the madhouse. From the sounds of it you have yourself a very pretty Mk2 Bantam, comes in various guises, the two speed ones are either 1600 RPM version or a 2000 rpm version.

The original motor is wound as a 4 pole or a 2 pole machine, and the connections to it go via a multipole four position switch (high/off/low/off) located under the front of the chip tray, The original motor will have been taken off because the windings need 400 volts and the conversion to run in delta on 230 volts is too complicated.

Unfortunately the 2 speed motor I took off mine got scrapped in the last factory move, but I'd stick with the inverter for sure. High and low speeds - particularly the ability to go below the marked bottom speed on a large diameter item - soft start, dynamic braking and all the other advantages of a VFD. Assuming, as above, that the inverter has these functions. If not I would spend the money on fitting one that does, not resurrecting the original controls.

Power limit with a geared head machine is unlikely to be a deciding factor in a hobby shop, and if it is I suggest a Bantam isn't the right tool for the job.

If you do want to return the electrics to original all the details are in the user manual, copies often on ebay or from Tony at lathes.co.uk. There are circuit diagrams for all the variants.

HTH Simon

Tom Walker 113/08/2020 14:00:08
45 forum posts
6 photos

OK, I can see there are a few things to consider.

My Bantam seems to have a single speed motor, because the switch is only On and OFF. I will see if the plate states otherwise,( though I dont really know what Im looking for).     It came with a variable speed inverter, so initially I ran it off my single phase supply.

I did make some (probably bad) assumptions. ..............

1. It felt a bit "weedy" (probably the soft start).

2. If you have 3 phase, everything should be on it.... you will have more horsepower, which HAS to be a good thing.

3. I didnt think that the fastest speed was fast enough, in either inverted form or with the single speed 3phase motor. When tuning small jobs, I thought I could do with more revs. (I didnt put a rev counter on it in either form though.)

So the easy thing to do was to take off the inverter, and re-jig the connections to give me 3 phase. Then I read about the 2 speed motor, so that has become the Holy Grail. Just how my mind works!

Thanks for the advice so far, please let me know what you think.

Tom.

 

 

Edited By Tom Walker 1 on 13/08/2020 14:02:48

Edited By Tom Walker 1 on 13/08/2020 14:24:29

Tom Walker 113/08/2020 14:13:16
45 forum posts
6 photos

The inverter I took off is an IMO CUB5A-1. Outputs 0.75kW/1HP. 5.0A

Howard Lewis13/08/2020 14:28:33
3536 forum posts
2 photos

My lathe (12 " swing 24" centres ) is not really in the Colchester class, but as part bf the deal, to buy new, the 2 hp single phase motor was replaced by replaced by a 1.5 hp 3 phase with VFD.

So may be yours appears a bit "weedy" because it is underpowered?

What power was the original , presumably three phase, motor?

Having said that, have never found anything too much for the 1.5 motor on mine. maybe i don't work it hard enough!

Howard..

Tom Walker 113/08/2020 14:38:32
45 forum posts
6 photos

OK, so the motor plate says all this. It is an AEI motor.

Type:    BK.2410 CG B56

Volts:    220/250-380/440

Phase:   3      C/S: 50/60

HP : 1       A: 2.82/1.63

RPM:    1425/1725

BS 170: CONT (not very legible, may be wrong)

So, does the dual figure for RPM mean it IS a 2 speed motor?

 

 

Edited By Tom Walker 1 on 13/08/2020 14:38:55

Edited By Tom Walker 1 on 13/08/2020 14:40:24

Tom Walker 113/08/2020 14:52:34
45 forum posts
6 photos

Probably not because that is only a 21% increase.

Andrew Johnston13/08/2020 15:46:14
avatar
5635 forum posts
652 photos

They're the speeds for 50Hz and 60Hz. And the two currents are for 230V delta and 400V star respectively.

Andrew

Tim Stevens13/08/2020 18:00:42
avatar
1259 forum posts

Hello Tom Walker

It is not general in engineering (or the rest of stuff) to evaluate the power of a component by feel. Especially if there is no information about how the feel was detected or measured. And even if there was, weedyness is not a unit (metric or imperial) to be found in any of the various text books, etc. But stick with it Tom and welcome to the Forum. I changed my (smaller) lathe from a single speed motor to a variable inverter system and I would not go back - there are so many advantages.

Regards, Tim (mid wales borders)

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
cowells
ChesterUK
EngineDIY
Warco
emcomachinetools
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest