bantam 1600 electronic problem

This is the same as mine

That is a two speed motor one so back to square 1

Jason has it - that initial picture of Andrew's has the position for the "L - H " switch for the two speed motor, but somebody has removed the switch. So no two speed pulley drive as per the pictures of the Colt from Lathes.co.uk.

I converted mine to single phase, hated it, converted it back to three phase but with a VSD, making the best of both worlds. I've got mine configured so the original L - H switch is now a digital input to the VSD to tell it to run at 100 Hz to get the higher set of speeds, though I hardly ever use them. The other trick I've found is to set the VSD to run (low speed) at 60 Hz, then the lower speeds through the gearbox are all set up by 20%. I use mostly carbide tooling - the faster speeds are a bonus.

The original L - H switch is a 6 pole 4 position rotary switch, probably still available out of the Kraus and Naimer catalogue. It switched the motor windings to change speed electrically. With a VSD all you need is a simple single pole changeover switch.

There is some stuff about converting a Student HERE and some more HERE and HERE

HTH Simon

I will have to make do then or purchase an original motor.

Andrew

If you purchase an original 2 speed motor you will need 400v 3 phase supply, if not a rotary converter or similar to run at the 400v required.

It would be less cost to get a 230v 3 phase motor and VFD plus it would give a greater stepless speed range.

Emgee

Thanks Emgee starting to wish i never bloody bought it.Can't use hi-lo speed can't use the apron leaver to start the machine plus need to get re-wired and new parts lol story of my life

If i do manage to get a motor will it use twice the electricity?

Will it? Plenty of single phase motors were two speed. Just choose the number of poles.

Anyone know what the original two speeds were that the motor ran at? could be the one you have is somewhere between the two so may give a useful range eg 60-1500rpm

Could i use a two speed pully from the motor or is that defeating the object of purchasing this lathe ?

On my Mk1 1600 motor speeds were 1425 and 2800 changed by the pole changing switch, this gave max 800rpm in low speed and 1600rpm in high.

Emgee

You probably could convert to a pair of pullies but obviously not as simple as a switch to go through the full range of speeds. Another option may be to change the existing pully from the motor to the input shaft to get a mid way spread of speeds and just leave in at that. If the input speed were upped by 50% rather than double you would have something like 50-1200rpm in eight increments just by using the headstock gears

Thanks Emgee, sounds like Andrew will just get the 800rpm with what he currently has.

Andrew, please do not get disheartened, there are several ways to sort it out, when you do you will have a super machine, that is as good as you can get in the size range, I have had mine for 35 years or more, and a delight to use. It has many features that do not appear on hobby machines that make life easy. If it were mine I would bring it back to original specification, as the apron lever is so handy. As you can see from the other posts, plenty of folk have converted theirs to VFD drive, so could well have original parts available. I have the original switchgear on mine, plus the original 3ph 2 speed motor, and run it from a Transwave converter. This means I can use the original suds pump as well, which I find really handy. I did burn the motor out about 15 years ago, and got the original rewound.

Chris Gunn

Thanks everyone for all your help i think i will try to obtain an original motor and VFD drive.And i agree Chris the apron leaver is a handy thing to have.When would this machine of been produced is it the 80s ?

Don't rush into anything yet. Although the single-phase motor and peculiar controls aren't ideal, they may be 'good enough' for whatever it is you intend to use the lathe for. If the motor runs the lathe should cut metal. Possibly the eccentric single-phase conversion is merely irritating rather than a serious problem. I'd use the lathe for a few months before deciding what to do next.

Two reasons for slowing down:

• To assess how much the single-phase set-up matters in practice. Much depends on what the lathe is for. A business wouldn't mess with a lathe like yours: cheaper and quicker to replace it with a machine in Good Working Order. But the lathe may be absolutely fine for home-workshop duty, or for learning on. What type of work do you do?
• Before fixing the electrics, you need to assess the lathe's mechanical condition as well. With the power off, spin the chuck by hand and confirm everything moves as expected: at this stage look for gross issues like jambs. Once reasonably confident, run the motor and cut metal. Turning, facing, drilling, boring and threading reveal problems like nothing else! All being well, the lathe's controls will work as expected, with no smoke, electrical tingles, crunches or wobbles! The machine will cut straight and produce an acceptable finish. In the worst case, cutting metal will reveal serious bed-wear, broken gears, knackered bearings, worn-out lead-screw, done for half-nuts, cracked castings, bodged repairs, a bent-spindle, missing parts, and headstock and tailstock misalignments etc. The cost of fixing a thoroughly decrepit industrial lathe is shocking: a few new spare parts may cost more than the second-hand value of the whole lathe! Best not slide into throwing time and money at a total lemon by accident.

Don't panic! Most lathe problems can be fixed without breaking the bank, or worked around by the operator. It's amazing what's done with less than perfect machine tools. But best to identify all the big nasties, if any, before ordering a spendy new motor and VFD or headstock bearings. The forum is better at answering questions about specific nasties than generalisations.

Dave

Chris if i have all the original parts what motor would you recommend and what transwave converter

I have machined some aluminium bar and drilled holes with no problems.I mainly machine aluminium but i just wish i had full use of the lathe hi-lo speed and the use of the apron leaver to power up the machine.But it all seams abit to complicated for someone with my knowledge of electrics and would probably cost a fortune to put back to 3ph.

If i purchased a transwave rotary converter is it just a case of getting a 2 speed motor and wiring it in

Andrew, I am using the original 420v 2 speed 3ph motor as supplied with the original machine. I am using a 3 KW Transwave capacitor type static converter, which I bought when I got the lathe. I fitted a 3ph plug to the original machine lead and plug it in. I use the same converter to run my Bridgeport. I have blown a capacitor a couple of times, and I took it to Transwave who are not too far away, and they repaired it while I waited. They told me my unit predated their numbering system, so it is an old one, but cannot fault it and the service. EmGee gave the motor details in his post. Good luck.

Chris Gunn

Thanks Chris but they are not cheap from what i have seen but you get what you pay for.