View Full Version : Minit lathe - can you help ID my wiring?!

02-08-2009, 08:29 PM
Wiring no workee

02-08-2009, 08:40 PM
is it the same as this? that i got from ebay.


If so i can take some pictures of the wiring for you?

02-08-2009, 08:59 PM
It looks remarkably similar!

The one I have is an Axminster C2 ....


All info is welcome - so if it's not too much hassle, photos would be great.

Once I know which are the AC mains in connections (there's a veritable plethora of switching going on!) ...and the DC out, then I'm off to a good start, but at the minute I can't trust a thing - wouldn't want to connect AC mains across the outputs!

John S
02-08-2009, 09:07 PM
block 1 has six connections
below each connector has some ID written on the PCB as follows
Connectors 1 & 2 ....."Gang" (possibly a ground connecton?)
Connector 3 ....."L1"
Connector 4 ..... "L2"
Connector 5 ......"A+"
Connector 6 ......"A-" (thesetwo look suspiscously like theycould be the DC outs to the motor)

Ok, now Connector Block 2
Connector 1 ......"K1"
Connector 2 ......"K2"
Connector 3 ...."P1"
Connector 4 ...."P2"
Connector 5 ...."P3" these P1-P3 seem to go to the speed control pot & match up with the wiring diagram, so these ones at least are solved!
Connector 6 ....."P4"
Connector 7 ....."P5"
Connector 8 ....."P8"

There is one little connector block with just two connections at the other end of the board (near the Output thyristors)...one connector is labelled K1 & the other K2.

These machines share common wiring between machines.

L1 and L2 are mains
A+ A- are the motor connections

P1, p2, p3 are the pot

K1, K2 Usually wire to the start switch as an inhibit so that if it trips you have to switch start off then on again to reset.

The one I can't help with for definite is P5 and P8.
on the X3 these have a jumper fitted.


02-08-2009, 09:14 PM
Thanks...that's actually a great start (& I had an inkling that was the case), what threw me is the reference to L1 & L2 on this wiring diagram in the manual (which you'll see has a different number of connections on it to my board anyway!)...L1 & L2 look to be both attributed to the DC Motoros & AC mains!

http://img5.imageshack.us/img5/8084/wiringe.th.jpg (http://img5.imageshack.us/i/wiringe.jpg/)

Any idea what the top two connectors at the other end of the board (in my photos) might be for? (I'm guessing possibly a chuck guard switch?)

John S
02-08-2009, 09:24 PM
K3, K4 are estop guard switches.

PM sent as well.

02-08-2009, 10:23 PM
Thanks to John's comments, I now have enough to be getting on with, so Gary - no need to photograph your wiring.

Also, someone on the zone also pointed me to the wiring diagrams on the little machine shop, where I found the following wiring doagram, which at least outlines what the aformentioned connector codes are for (& this marries nicely with John's info)...


Many thanks.

PS What's with editing Subject headings? I corrected the typo using 'advanced edit' ...but it still shows up as minit lathe?!

07-08-2009, 12:11 AM
Having had fever all week (stuff swine flu - this was much more serious - man flu), it's fortunately waned sufficiently this evening to take a closer look at my dead board.

I think I've found the fault :eek:...about 25% of the components on the PCB's lower surface appear to have been nuked ....

http://img193.imageshack.us/img193/9136/33190882.th.jpg (http://img193.imageshack.us/i/33190882.jpg/)

(surprisingly...there was no inkling of those scorch marks until the board was removed from the recess)

http://img9.imageshack.us/img9/1282/50702126.th.jpg (http://img9.imageshack.us/i/50702126.jpg/)

Not looking like such a good buy now! (but to fair the seller did say it would need a new board - but oh no, did I pay much attention - nah, I'm way too cocksure thinking I could likely fix it! :joker:).

I don't suppose anyone has a less knackered motor speed control board that I can buy/fix? ...this one's beyond the pale!

10-08-2009, 10:08 PM
Out the frying pan & into the fire ...there's nobody holds stock of the pucka replacement (not that I[d pay eighty quid anyway), so John S pointed me to a suitable Danfoss control board.

well, it turned up today & there are a few spade connections that aren't obvious!

http://img6.imageshack.us/img6/4051/boardddd.th.jpg (http://img6.imageshack.us/i/boardddd.jpg/)

There are an awful lot of connections on it & just wondered if anyone here has a clue as to what they refer to...

L1 & L2 I guess are mains

two unmarked Spade connectors (I'm assuming these are the DC out)

SP1, SP2 & SP3 I guess are the speed control pot connectors.

INH presumably means inhibit (though it's not clear whether this is an input or output)

A1 (two spade connectors)

F1 (one spade connector)

A2/F2 (two spade connectors)

10-08-2009, 10:49 PM
That is a Vari-speed drive and the two terminals are for a current sense resistor to set up the drive for various size motors, a bit like resistor settings on stepper drives, pm me your e-mail address and I'll send you a pdf of the manual.



10-08-2009, 11:42 PM
Man I love this site....my Sieg lathe board is nuked, I post here accordingly - John S put sme onto a dirt cheap replacement on Ebay that I'd never have found/considered ...it arrived today with no documentation (& seller not likely to have any) , I ask for help & within an hour or so, I have the full documentation (that not even the manafacturer could furnish me with!) - great stuff.

Thanks guys! :beer:

** Looking at the maual I'd have likely blown it to pieces as it's got some recommendations that I'd gave actively done the opposite - eg ...don't ground the switch or speed pot, etc! (my sieg board switches are grounded)

Lee Roberts
11-08-2009, 12:46 AM
Good im pleased for you :beer:, reciprocal love !

14-08-2009, 03:42 PM
Ok, I'm on the home straight ...I just need a sanity check re the DC motor connections & the 'current sense' resistor.

Firstly, I reckon the DC motor connections are A1 & A2 on this diagram (there are spade connectors marked as such on the PCB)...

http://img9.imageshack.us/img9/2937/wiring1w.th.jpg (http://img9.imageshack.us/i/wiring1w.jpg/)

(John S, confirmed that on the original Sieg board that A1 & A2 are the DC Motor connections & I gather this must be a standard naming convention, but those F1 & F2 connectors are messing with my head!)

Ok, next challenge' ....current sense resistor! This board talks of having an external current sense resistor, but if you look at the chart, it seems ludicrously low...

http://img12.imageshack.us/img12/7127/wiring2z.th.jpg (http://img12.imageshack.us/i/wiring2z.jpg/)

my motor is 250W, which apparently is 1/3rd of a horsepower - therefore looking at that chart it needs a current sense resistor that is 0.027 Ohms - are they having a laugh?

Where on earth will I be able to source a resistor such as that? (Danfoss apparently don't make these driver boards any more ...not sure if Graham do) ...since the resistor is in series with the motor ...it's going to have to be able to handle a fair whack of current...therefore I'm figuring it'll need to be able to disappate a fair bit of power too?

Has anyone experience of such current sense resistors? Is there a 'frig' where I can do away with the darned thing?

Many thanks

14-08-2009, 06:32 PM
No the resistor should only have to dissipate 0.5watt.
so at 4 amps and 0.027 ohms then 4 x4 x 0.027 =0.432 watts.
You may have to parallel some to get near the value. Just did a quick search so far nothing in uk.


just found http://cgi.ebay.co.uk/Vishay-LVR05R0250FR55-0-025-ohm-1-Resistor-lot-of-10_W0QQitemZ390075831204QQcmdZViewItemQQptZLH_Defa ultDomain_0?hash=item5ad254d3a4&_trksid=p3286.m63.l1177

so should be available in UK

14-08-2009, 07:10 PM
Thanks Peter, I couldn't find anything (well nothing less than £10 - for ten resistors...eeek!) , so I paniced, then got creative & 'rolled my own'. I happened to have some 29SWG enamelled copper coil wire lying about ....& I worked out that two strips of 31cm in parallel equals about 0.027 ohms, as apparently it's 0.173 ohm/mtr at 20C), here's a pic of the result....

http://img25.imageshack.us/img25/7835/17341875.th.jpg (http://img25.imageshack.us/i/17341875.jpg/)

& it actually works! My lathe is finally turning again!

Ok, so here's my final 'puzzle'

I've wired in a 'normally open' chuck guard switch provided (working on the theory that being new to lathes, if I don't have one of these I'll definitely end up with a chuck key in my cheek).

For the life of me I can't figure out how it can be 'triggered' (I only received a 'box of parts' from the seller)....there doesn't seem to be any cam/'sticky out bit' (technical term or what?!) on the chuck guard that can activate it the switch lever. Worse still the screws suggest the lever switch goes face down into the plastic recess hown in the photo below - that doesn't compute as there's no way in hell it can be 'activated' then!

If anyone has a mini lathe with a chuck guard switch setup similar to this, I'd really appreciate a photo/explanation of how it all fits together!

http://img19.imageshack.us/img19/5535/switchb.th.jpg (http://img19.imageshack.us/i/switchb.jpg/)

14-08-2009, 07:18 PM

Firstly you only need to use terminals marked F if you have a shunt wound motor, I am assuming that you only have two wires coming out of yours if so you just use the A marked terminals.

The sense resistor is used in some drives as part of a feedback circuit to limit the amount of current the motor can draw, and help prevent your motor from burning out, it can also help out with low speed torque issues, this subject can get quite complex so we'll leave it here!

Anyway this rs part number should help you: 199-6356 it is for a 0.03 ohm 6W resistor which is just about right for you. As peter correctly says your dissipation will only be about 0.3 - 0.4 w.

You posted while I was typing, glad you got it going Rob.


14-08-2009, 07:56 PM
Hi I have some 0.082R 3% 10watt resistors they were pulled from some large redundant PSU’s. If you have the room to parallel them up, you are more than welcome to some for the price of the postage.

14-08-2009, 08:18 PM
Hi Ivan,

Thanks for the kind offer....what I've 'lashed up' seems to be working & there's not a great deal of room in there (I actually had to push my coiled 'resistor'/wire down in order to fit the chassis back on to the lathe body), so I'll just stick with what I've got.

Very good of you though ...many thanks,