Ferrite rings

I know Google or similar should be my friend here, but struggling to find the right item.

I have a Gunson Superstrobe timing light for the car, but the ferrite ring on the HT pickup is cracked, so obviously doesn't work any more.

It's a square U shape and square cross section, as per the attached photos.

There is a sliding cover with a bar ferrite encapsulated to complete the magnetic circuit, and a coil round one leg of the U. I did try using a slice out of a round ferrite ring, but can't get it to work.

Anyone any thoughts for a supplier please?

I did contact Gunson, who put me in touch with their spares supplier, who in turn would only quote for a full replacement lead; Can't remember the exact price, but it was north of £50.

The U shape is dimensioned as follows;

i.e. approx 6mm x section, 16.5mm high, & 25mm wide

Edited By peak4 on 18/03/2016 12:44:03

You might have luck with RS here...

**LINK**

Good luck.

Jon

Not many of us use these now so keep an eye on the usual sites for someone selling a complete one.

Unfortunately, unless I'm missing them, they only list 2 U ferrites, which are far too big, but thanks anyway.

Regards

Bill

Edited By peak4 on 18/03/2016 13:35:00

Thanks Chris, I already did that and have a working one now, but I'm trying to get my old one up and running too.

It's the later model with a dwell meter as well, but I've been keeping an eye out for a cheap one of either style as I assume the ferrites will be the same.

I don't really want to spend a load of dosh on another working one, as I'll still have the current one awaiting repair. Shades of Groundhog day.

Have you tried gluing the broken one together?

I would expect that if the two faces were in good contact (a miniscule glueline) that it would work as well as it originally did.

Ian P

If you go onto Vintage Radio or Golborne Radio, you could put in a request, some one may be able to source one for you or know an equivalent. They are very knowledgeable people. John

Have you checked that the winding has not been damaged. Check with a meter that it is not open circuit. If the original core is stuck togeter with superglue or a THIN film of araldite I think it should work. I did a search on ebay for "ferrite transformer core U" and found this current transformer that may do the job. When I built one many years ago I just used a ferrite ring and it worked.

Les.

As suggested, you should just glue it together again. As long as no significant fragments got lost and you don't make a large gap anywhere, it should work just fine. For production, these are generally glued together with cyanoacrylate or epoxy adhesives, the former often with an activator to make it "go off".

If you don't want to try that but can find a core of the correct physical dimensions, you shouldn't need to worry too much about the magnetic properties. As long as it's ferrite, rather than eg powder core I'm sure it will work fine.

Murray

Many Thanks folks, I'll give it another go.

Much appreciated.

bill

Bill is that a Marlin on your avatar ? In my car trial days they always did well on things like the MCC long distance trials. So much more comfort than a Dellow !

Many computer power supplies have leads wrapped around ferrite rings, they are used for reducing electrical noise

If you can get hold of an old one try pulling it apart You may find a ring that will work

Regards
John

Chris, the Marlin may be comfier, but it's no where near as cute! See my avatar!

Andy

It is indeed, but not a trials car. This one's a Berlinetta, built by the previous owner from a Mk3 Cortina; 2l Pinto with a 5 speed type 9 box.

He did make a decent job of the build,as his day jow was something to do with building limos for Jaguar Daimler.

I just wish he'd discovered rivnuts though. As I work on bits, I'm gradually replacing loose nuts with captive ones.

My other Avatar's a Lightwight Landrover. (V8 auto)

Lightweight Landrover, that's an oxymoron.

Frank

There are lots of Ferrite cored transformers etc with cores about the size you want in modern electronic gear, you'v got to be a right magpie to get a good junk box.

Ian S C

The Lightweight Landrover was an actual model, and not the first contradiction in naming cars.

The preferred name is 'Air Portable', and they are the ones with the corners chamfered.

Cheers, Tim

.

Quite so, Tim ... and a fine early example of MoD Procurement 'manipulation'

**LINK**

MichaelG.

Yup, a friend of mine bought one from an auction of ex-military vehicles, went a bit pale when I asked him if it had been air dropped on the parachute pallet.

No top, no heater and half doors  so he really froze driving it from Leeds to the south coast of the Moray Firth in August

Edited By Dod on 20/03/2016 21:47:31