EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: gg64 on December 17, 2020, 07:57:42 pm

Title: 1 pole or 2 poles switch for small angle grinder
Post by: gg64 on December 17, 2020, 07:57:42 pm

Hey,

I am trying to fix a small angler grinder.

I tried to get the OEM part for the switch could not find it (4terminals/2poles Normal Closed, way off center switch).

Photos will be provided in the next post.

No ground wire is provided and I am not sure why.

I found a potential workaround that is to used those kind of microswitch.

I found a 10 (3) A 250VAC seller from germany on ebay.

Here is the listing: https://www.ebay.fr/itm/323907219752 (https://www.ebay.fr/itm/323907219752)

I got some with small lever, small lever with "wheel".

I tried two alongside of each other. But it barely working but it would be really handy if I can use only one.

(I can adapt it with plastic PCL since this is an air intake the temperature is most likely not going above 62°C anyway).



It is safe to only use one pole switch on a small angle grinder ?

Or 2 poles switch are meant to avoid giving shock to the user if something goes wrong during grinding ?

Thanks you.

Title: Re: 1 pole or 2 poles switch for small angle grinder
Post by: rvalente on December 17, 2020, 08:59:52 pm

That up to debate but....

Usually angle grinders are double insulated devices, so yes, its safe to switch just one phase to turn it of.

Being double insulated the protection conductor (grouding) may not be required, that may change from standard to standards but here in brazil is not (also here, the neutral is grounded so is always a low impedance path)

If you run on hot + neutral (120ish) try to cut the hot (mains)

Many single insulated 230ish appliances only switch one phase like: hair driers, toasters and microwave ovens

Title: Re: 1 pole or 2 poles switch for small angle grinder
Post by: gg64 on December 17, 2020, 09:27:44 pm

Hey,

here are some photos of the old switch:

Does anyone know where I can find one of those ?

Title: Re: 1 pole or 2 poles switch for small angle grinder
Post by: gg64 on December 18, 2020, 12:02:21 am

Well I used one switch with a small lever with "wheel" + some PCL plastic + some drilling to make way for the lever +  3 mm steel wire to hold everything together but allowing this to be removed.

I think it is turning the right way.

Are you guys interested in this thing photos ?

EDIT: photos

Title: Re: 1 pole or 2 poles switch for small angle grinder
Post by: rvalente on December 18, 2020, 04:34:19 pm

For the price of these machines nowdays I think you went the correct way.

Here in brazil if the field or the armature windings goes bad its not worth fixing. Usually the next thing to fail are the bearings