Whats going on with this drill?

So I bought a corded drill of ebay attracted by its low RPM but now I look at it I realise something is off.

Thats the entire drill, notice the 3 pin plug.

Thre is the information on it, notice the 110V.

Did I just buy a dud 99p drill? Seller said it probably works but it was his granddads and he doesn't have a transformer to test it. If it has been run off 240V what are tha chances the insides are baked?

Hi Rainbows,

A lot of American tooling is 110 volt and will need a transformer in order to be used on UK supplies.

What is worrying is the presence of a 13amp plug being fitted, giving suspicion that it has been used on a 240v system.

It would be prudent to have it tested properly before use as it is obviously getting on in years.

I was going to open it up to check if it needed new bearings, brushes and grease and such anyway.

Assuming it isn't already burnt out would one of those yellow transformers you get for construction sites be suitable? I know the voltage is right but I don't know if the frequency is right too.

just had the same problem myself with a bench grinder, plugged it in worked fine then I noticed the label. no damage done put on correct plug and its working ok on 110v. the original owner may have been running it off his own bodged up 110v circuit. what you need is a yellow site transformer. if it has been burnt out it will smell. i buy lots of these old drills and they are very tuff.

As said smell it. A transformer will cost a lot more than 99p, so donate it to local junk seller. I could suggest a bodge to test but that will have H&S howling.

The guys are right about the smell, if it has been cooked it will leave you in no doubt. There is actually a reasonable chance that it might survive being plugged into 240V for a short time. I have a 110V fine feed unit on my mill drill that was given to me because it had been plugged into the 240V mains and gone pop. The only thing that had actually blown was an interference suppression capacitor, so it was an easy fix.

The frequency does not matter too much for this type of motor. The speed is not determined by the frequency.

If you do get it going with a step down transformer, make sure that the transformer is a double wound type, not an autotransformer. The difference is that with a double wound type, the secondary is isolated from the primary, which gives you an extra degree of protection with an old unit like this. With the autotransformer type, depending which way around the primary ends up connected, you can end up with 240 V between one end of the motor and the earthed case, which is not ideal on a machine only intended for 110V.

John

It is a good thing I kept that 110v tranformer from that auction lot I got a while back. No idea if that is double or auto though. Its the yellow box type.

Looks as if it's from The Ark. Whether or not it's been damaged by being used on 230V, I'd suggest you run it from an isolation transformer or an RCD at the very least, given that it seems to have had a tough life. I've no idea what the internal insulation requirements were back in those days.

When you dismantle it, make sure it has a solid ground / earth connection to the case, at least as heavy as the L and N connections, all the way back to the (120V) plug.

The yellow transformer will be a site transformer so will have all the safety features. My mate tried a 110V saw on the 240 mains 'cos it would not work on 110V, ,found that his mains was only about 180V instead of 240, no harm done.

That would be perfect. Frequency can't change through one and the difference between UK 50Hz and US 60 HZ won't matter. Some, if not all, of the yellow boxes are CTE or centre tapped for extra safety too.

I wouldn't put my hands round it and turn it on..It is probably well made, but I have better things to waste my time on than something that might electrocute me.

If a 110V transformer is correctly wired (and the sealed units should be) the earth will be wired to the centre tap of the 110V. this means that no live part of the drill will be more than 55V from earth.

Though the Americans need thicker conductors than us (for higher current) their system is a fair bit safer than ours!

Neil

We used to use 55 Vac to line power cable TV amplifiers on the basis that 55 Vac was the highest safe voltage.

I thought that the domestic electricity supply in the US was two phase with 110 V at most outlets having one side earthed and 220 V for things like cookers with centre tap earthed. So it is still potentially lethal.

Russell.

I can never trust a electrical system that uses such feeble and fragile plugs.

with things like that i put a cable tie around the switch then turn the thing on at the wall.

Hi, a 110v yellow site transformer will be OK as they are just as Neil has pointed out centre tapped, so that your are only ever likely to be exposed to 55v, which is deemed to be a safe level in industrial and outdoor situations. The majority if not all of them will have a built in thermal overload so that if you start drawing more power than the unit is designed for, for any length of time, the output will be cut off until the unit cools down enough to be reset. This drill you have is an old style one which would not be allowed to be used in an industrial environment because it is not double insulated and an earth wire must be used with it even though it is only 110v. All yellow site transformers have a three pin socket outlet with the thickest pin hole connected to earth, but of course the power lead going to the transformer must be earthed in the first place, because the site transformers are themselves double insulated.

Regards Nick.

P.S. the one at the top of this list would be suitable http://www.machinemart.co.uk/shop/range/guid/C1C63496-8E8F-4533-A0D9-BF9A15436A24?da=1&TC=SRC-110v%20transformer

Edited By Nicholas Farr on 04/05/2015 16:24:15

Rainbows.

What with this post and the home made arc furnace post can you supply a post code where you live please ?

Reason is I want to check I'm at least 3 counties away from you.

I haven't even tried my electrical arc ignition system for a waste oil furnace though!

Also out of curiosity is it possible to make it double insulated? I'm wondering is there is some sort of insulating spray that could be applied to the inside of the drill casing.

all you need to do with it is check the wires from the switch to the windings are ok by covering them with heat shrink sleeving, i fix these things up all the time. just do not use it in the rain in bare feet.

Know a friendly PAT tester?