TOROIDAL TRANSFORMER fixing - Page 1
Forum section: electronics / general

author: akis
author_rank: Frequent Contributor
timestamp: February 12, 2015, 09:02:52 am
content: I have some older toroidals I would like to use and I have lost the fixings they came with. Typically a round metal plate of appropriate dimensions with an indentation in the centre to allow a hefty bolt to thread through and connect to another such plate at the other end of the toroidal, sort of sandwiching it in between. Would you know where I can buy these from?PS: I can easily make my own brackets, made of aluminium sheet, they would be square rather than round, but I would not be able to press in the intentation which allows the bolt to be fitted in flush with the bracket.

author: Whales
author_rank: Super Contributor
timestamp: February 12, 2015, 10:54:12 am
content: Possible alternative: roughly cut a circle of flexible plastic sheeting if you can find some lying about.

author: rdl
author_rank: Super Contributor
timestamp: February 12, 2015, 03:03:11 pm
content: Your idea would work. You should use a layer of insulating rubber/plastic for the top and bottom, as Whales has said.One place I found on eBay. Price is pretty high though. May be others out there, I didn't look that hard.www.ebay.com/itm/Toroidal-transformer-mounting-set-accessory-material-fixing-/311211740783You might also try wandering around in your local big box hardware store or talking to the people at the auto parts place for ideas.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 12, 2015, 03:17:49 pm
content: Or use a few big-ass cable ties.

author: langwadt
author_rank: Super Contributor
timestamp: February 12, 2015, 03:20:48 pm
content: Quote from: mikeselectricstuff on February 12, 2015, 03:17:49 pmand remember not to use metal cable ties

author: akis
author_rank: Frequent Contributor
timestamp: February 12, 2015, 03:38:17 pm
content: As far as I know, a bolt or screw inside the toroidal also sits inside the magnetic field and if you attach the bolt to the chassis which is earhed you will be creating a shorted winding which will probably blow up something. Am I right?

author: Refrigerator
author_rank: Super Contributor
timestamp: February 12, 2015, 04:01:27 pm
content: Quote from: akis on February 12, 2015, 03:38:17 pmWrong, there won't be a loop thus no current will flow, it will form something more like a "T" than "O".

author: akis
author_rank: Frequent Contributor
timestamp: February 12, 2015, 04:14:50 pm
content: I meant to say " a bolt though the toroidal bolted on the chassis on both ends "

author: SeanB
author_rank: Super Contributor
timestamp: February 12, 2015, 06:50:28 pm
content: Bolt through with both ends attached to chassis is a shorted turn, but a bolt through with a big fender washer and a compliant washer made from either neoprene or synthetic high temperature rubber is fine. Do not overtighten it either, it just has to hold it from moving with vibration, tightening it to the point where it crushes the outer insulation will cause shorted windings.Another option is a big blob of acetoxy free silicone in the centre with a bolt inside it.

author: akis
author_rank: Frequent Contributor
timestamp: February 12, 2015, 07:42:41 pm
content: In the end I re-purposed some smaller fixings from smaller toroidals and we are all good. The ones on ebay are particularly expensive and they come with only one plate for some reason so you'd have to buy two. Might as well buy a new toroidal!

author: Refrigerator
author_rank: Super Contributor
timestamp: February 12, 2015, 09:59:48 pm
content: Hmm, i just checked ebay and it does seem like those mountings go for quite the penny.If you have a bench vice i'd suggest you could cut out some 1mm thick sheet metal, then place a large steel ball in the middle of the plate, put a block of wood behind the plate and press, but not too much so you don't tear the metal, this will give you that indentation that you are looking for, at least i found this method to be quite useful in some situations.