SIP Mini Wood lathe 01492 - Runs Away

[Merlott]

Hi
new the forum, so please be gentle. We have inherited a SIP Mini Wood lathe model 01492. A problem has arose, when the lathe is started, at the lowest speed setting, it suddenly takes it upon its self to increase the speed to medium/fast, without me touching the speed regulator. Obviously I turned the lathe off, waited , restarted, now it starts at a medium speed and turning the selector most of the way goes to fast, so no slow speed available , only medium and fast, no real variation. I presume the speed regulator is on the blink?
Any opinions, advice gratefully accepted

 

[Paul Hannaby]

It could be just dust in the potentiometer (the bit you turn to adjust the speed). Try blowing / vacuuming it out thoroughly and if that doesn't work, get it replaced, they only cost a couple of pounds.

 

[Lightweeder]

It could be just dust in the potentiometer (the bit you turn to adjust the speed). Try blowing / vacuuming it out thoroughly and if that doesn't work, get it replaced, they only cost a couple of pounds.

This made me laugh. I have a spot like that on my Record Power VS and husband always tells me 'it's dust on your potentiometer'. Maybe he's not as dumb as I think he is

 

[Phil Pascoe]

My wife's never said I've dust on my potentiometer when I go too fast.

 

[Melinda_dd]

hi

the lathe you have inherited is the same as the first lathe I ever had .
it was a brilliant little lathe it went forever.

i can't offer anything about the speed thing but i will say that if in the future the motor has problems remember it has brushes. i had to replace mine a couple of times.

Enjoy it i know i did.It was the start of a very expensive hobby

 

[CHJ]

If it is a potentiometer track contact problem and you can get access by removing the potentiometer back cover, (WITH POWER OFF AND DISCONNECTED), a temporary fix may be obtained until you can get a replacement by rubbing the track with a soft (2b) graphite pencil.

 

[Merlott]

Many thanks for the responses so far folks, I'm going to Maplins later today, to see if they have a suitable potentiometer in stock or they can assist. I hope I can keep it going, its a nice lathe, perfect for the job in hand. I`ll keep you up to date.....

Edit = Yes I`ll give it a try with the pencil and potentiometer, if anything I`ll get to know how the inards of lathe works

 

[tekno.mage]

If it's anything like our club's Vicmarc VL100, the potentiometer fitted will be as cheap and horrible as they come - I can accept that on a cheap lathe which has to be built down to a price, but was disappointed on the very expensive Vicmarc lathe which otherwise uses high quality parts.

We had to replace the pot on the Vicmarc (due to very similar symptoms to your lathe) and replaced the cheap and nasty carbon one (not sealed against the ingress of dust and dirt) with a much higher quality sealed type. Cheap pots cost pennies when bought in bulk as lathe manufacturers would buy them and decent ones around a couple of quid. Spoiling the ship for a ha'penny of tar, there Vicmarc :-(

If you are buying a 1 off replacement pot, you'll probably need to pay around a fiver to get a decent quality one in somewhere like Maplins.

 

[Merlott]

Hi, well not good news, went to Maplins with the old one, they went on line and found a suitable replacement, same rating etc. Fitted, no real difference. I'm minded to contact SIP for further advice?

Unfortunately I could not open the old switch as it was a sealed unit....

 

[tekno.mage]

I've just spoken to my partner regarding this fault (he knows more about these things than me). If the motor in the lathe is a three phase one and the inverter (speed regulation box) is single phase in and driving a three phase motor, then your fault does not sound like it is caused by a duff inverter - this would either not drive the lathe at all or would have it spinning at full speed all the time. However without knowing more about your lathe, I don't know if this is the type of set up it uses. If the motor itself is single phase it's plausible that some speeds might work and others not. However, there are some other thing you could try....

1. Did you wire up the potentiometer correctly? (please let me know if I am teaching my grandmother to suck eggs here!) The connectors on the new pot may not be in the same place/order as the old one. You should be able to tell which of the connectors is the wiper (the bit that moves) on both the old and new pot by use of a multimeter and make sure you wire the new one up the same as the old.

2. You may have a wiring/connector problem - the connectors might be slightly corroded, or the wiring damaged - clean any corrosion off and visually inspect the internal wiring.

3. If all else fails you could try contacting SIP.