Output Transformer Laminations.

[Cressy Snr]

A question.

If an OPT core is in contact with the fixing bolts, which are earthed, do we have a shorted turn and all the inductance gone?
Both The BLS OPTs from Nick have continuity from lams to end bell via the bolts and I don't like it. Am I worrying unnecessarily?
Short of hanging the OPTs from a sky hook I'm at a bit of a loss as to what to do.

[Paul Barker]

You need insulating bushes (top hats). I used to have loads of them and have supplied them to a few people here. But I haven't yet got back into transformer winding so don't have any stock you have to order 1,000 of each size minimum.

So I would improvise. Use fibre or nylon washers and perhaps paint or varnish the bolts. ( the lams themselves are only isolated from each other by a thin layer of paint) I generally make a cork gasket (which you cut out yourself) between transformer and chassis as electrical isolation and anti-microphony measures.

[Cressy Snr]

Cheers Paul
There are fibre washers at each end of the bolts so the contact must be happening inside the lams.
I am just off for some 4mm threaded rod. This can be cut to size, and insulated with heatshrink tubing.
Thanks for the advice, my mind had gone completely blank.

[Paul Barker]

Yes that will do.

[pre65]

If you want M4 insulated top hat washers these might do.

http://www.ebay.co.uk/itm/Plastic-M4-in ... 232dbad07c

[Cressy Snr]

Cheers Paul/Phil,
Jobs a goodun.
OPTs mounted, laminations isolated.
Thanks.

Tattoo machine parts eh!
Now then Phil, you're a man of many hidden talents.
Can you do "Love" and "Hate" on my knuckles at November's Owston
once you've got your machine fixed.

[pre65]

Now then Phil, you're a man of many hidden talents.
:

Could be.