Member postings for Philip Coupland 3

It’s a Jack 563A - available in the UK for around £150.

I don’t know the answer to the question about the adjustability but there are a few videos on YouTube.

Posted by Howard Lewis on 04/03/2022 15:12:00:

With regard to keeping swarf out of the control board, there should be a "rubber" grommet to fit in the slot around the Leadscrew.

Arc Euro list it as C3-256 priced at £3 (plus postage )

If you have not got one, it would be worth fitting one to reduce the risk of expensive failures.

Howard

Hi Howard, I’ve no longer got the control board installed. Although I intend to do a little more work to protect the workings from swarf, the Jack sewing machine motor and ancillaries are all well sealed, much better than the original lathe set up.

Edited By Philip Coupland 3 on 04/03/2022 19:36:47

An epilogue…

It turned out that the motor was damaged too, so I decided to adopt a suggestion made on the forum to fit a sewing machine servo type motor instead. This was cheap and not hard to do and has permitted me to upgrade from the feeble 400W motor to a 750W unit. The speed controller supplied for the sewing machine works well too.

I haven’t finished the installation yet, there being some bodywork and other things to do but testing it today I found it worked very well. In fact, together with the new roller bearings for the headstock spindle the lathe is transformed. For example, parting off, which was usually a horrible experience, was done very nicely.

Hello John and thank you for your comment.

The manufacturers of the board say that: 'It is recommended that both AC line and armature fuses be installed'. I interpreted the latter as meaning a fuse in-line with the positive power wire to the motor - is that incorrect?

Thank you again OldVelo.

I think the manual you mention is one that I've found on the manufacturers site (https://acim.nidec.com/drives/kbelectronics/-/media/kbelectronics/documents/dc-drives/manuals/kbic_manual.ashx?la=en). I expect that I'll have a go, after I've marked the starting positions on the 'trimpots'.

My comment about my electronics education having stalled at the batteries and bulbs stage is the literal truth - I remember struggling and failing to understand the working of resistors in the Ladybird Book of the Radio. However, despite not having a brain that likes maths, I can follow a recipe (although perhaps not if translated from Chinese).

I'll have a look at your photos. I have already fitted one fuse to the + power lead to the motor.

Thanks Les.

Yes, the resistor is identical to the one that was blown.

I was surprised too that everything seemed fine until I put load on the motor.

The bearings aren’t tight in the headstock - they turn easily but I found that when released the locknut in the spindle the speed certainly increased although still not within the normal range.

An update.

The replacement KB Electronics horsepower resistor that I ordered yesterday from the helpful and efficient Axis Controls of Southport arrived this morning and I fitted it this evening.

I’d checked the motor for any more shorts and tested the board first just connected to a voltmeter. When powered up, turning the potentiometer caused the voltage to increase and then when I connected the motor (detached from the lathe) that also speeded up to a high rate in response to the control.

However, we are not quite there yet. When the motor was reinstalled and the drive belt fitted, I found that it would not speed up more than a little. It will certainly be encountering some more resistance than previously because of the new roller bearings fitted and perhaps the new metal high-low gears that I’ve replaced the plastic ones with. But the bearings haven’t been over loaded.

What I’m wondering is whether this is something that can be resolved by an adjustment on the circuit board or does it indicate that there are further electronic components that require replacement?

Once again, thanks to all who’ve contributed to this thread.

The suspected culprit - next to the bearing

I’m very grateful for all the helpful contributions made - thank you gentlemen.

I made further investigations this evening and found a possible cause - a curly piece of swarf, which had got in the back of the motor and was making a contact between one of the brushes and the casing of the motor. Happily the motor seems to be still in working order and spins happily with a 12V DC supply. Once this electrical problem is resolved I’m going to ensure that the motor is properly separated from such nasties. Incidentally, I wonder if there is any benefit from adding a fuse in-line with the positive supply wire to the motor - would that prevent this happening again?

The plan at them moment will be to try out the replacement resistor when it arrives. If that doesn’t work I shall probably have to buy either a replacement board or I may buy a complete control box (Amadeal) as its not a huge amount more and will avoid any problems with wiring in a board that may have different connections to mine.

For future reference, a full range of horsepower resistors is available from Axis Controls in the UK (https://www.axiscontrols.co.uk/). I've ordered one and we'll see if it brings my lathe back to life. Its a plug-in so I won't even need to get the soldering iron out.

Thank you OldVelo. With your information, I've identified the blown part as a 'plug-in horsepower resistor (9838)' from KB Electronics. These are available in the US although the cost of shipping and import tax seems excessive. I'll see if I can find them in the UK.

Hello Ian, well spotted! Despite my efforts to keep the workshop tidy all manner of swarf, splinters, chippings gets everywhere. It's a very small space and bits go everywhere.

Later today, I'm going to thoroughly check the output to the motor for shorts - it would be a relief to find one and know the cause of the problem.

I’m in England.

Thank you for the guidance on posting pics.

Here is the smoking wreckage below - the broken off piece came off the back of the rectangular white component.

One question occurs to me to ask is why is so much electronics necessary to control the speed of an electric motor? For example, an electric drill usually has the facility to control its speed without all this.

To briefly introduce myself, I’m hobbyist whose metal work interests are mainly related to motorcycles. My tiny workshop is crammed with many machine tools, including the lathe that is the cause of this request for help.

I have recently added roller bearings to the headstock and wanted to test the running of the drive belt so plugged it in but on turning the machine on there was a flash and a pop and that was that. On closer inspection inside the control box it was found that a large rectangular component marked 120V had the back blown off. I don’t know what this component is, my knowledge of electronics having stalled at the battery and bulb stage.

I hadn’t touched the electronics at all, merely unscrewed the control box and moved it to one side, leaving everything connected apart from the two earth wires going to the headstock, which I had reconnected.

I’m wondering if I could replace blown component (assuming I can identify it and find one) or is it likely that a whole lot of other stuff is gone. I’m also concerned to find out what’s caused the problem - if I end up spending a fail amount of cash on a new circuit board I don’t want to ruin it as well.

With thanks, Philip C

PS If I can figure out how, I’ll post a pic