I have a pcb transformer i wish to mount on a flat steel panel without using a pcb. There are four 3 mm hokes. Ideally id like to use nylon bolts but they would need to be 40 mm long, not sure they are avaikable.

Not sure but steel bolts make be ok but will they short out the laminations? probably not and even if they did, it shoudont impair operation as there is a bead of weld each side to hold them together. (Need to remind myself about transformer design). This would be best as it keepssoace required to a minimum.

So far im thinking of bolting al sheet then use cable ties through the holes, unless there are other suggestions.

Photo below.

Nylon sleeves and washers then slightly thinner steel bolts through the middle?

The 'standard' method is to cut a square hole in the sheet for the plastic insulator and contacts to drop through, then 4 steel screws.

The laminates make up the 'core' it not part of the circuit so no worries about shorting.


trans in amp

Not electrical shorting but magnetic. This is going back many years but from memory to reduce losses from eddy cuurents, the core is made from slices of iron insulated from each other, im guessing the 'shorting' depends on the contact area.... this is the bit i need to research.

Btw ive found two ebay sellers doing 40 or 42 mm m3 screws so problem is possibly solved, depends on how sturdy they are, steel would be preferred choice. I guess i could try it and see how hot it gets

Brass screws?

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Originally posted by Dingz
Brass screws?

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You won't get any magnetic 'shorting' by mounting this on a steel panel with steel bolts/spacers and nuts. This only occurs when you form a shorted turn which passes though the magnetic circuit, e.g. through the center of a toroidal transformer. This is quite difficult to achieve accidently on a transformer with E/I type laminations.

FWIW this is exactly how many valve amps mount the transformers on a chassis.