Small toroid mechanical fixturing

[matthuszagh]

I'm building a PCB circuit that requires a custom-wound toroid for use as a 3-winding transformer. The toroid will be pretty small: OD=9.5mm, ID=4.75mm (https://www.mouser.com/ProductDetail/Fair-Rite/5961000201?qs=Ca1fAiqt1aqSBOA35FqYWg%3D%3D&countryCode=US&currencyCode=USD). I'd prefer that the toroid not be mechanically supported by the transformer windings. Suggestions for how to support this mechanically? An enclosing case, especially one that does not allow water and IPA to enter, would be nice but not necessary. If using the windings for support is the typical solution, that would be useful to hear, along with any suggestions for how to make that robust (e.g., keeping the leads short).

[fourfathom]

A [machine screw / insulating washers / nut] through a hole in the PCB?  Zip-ties through holes in the PCB?  Glue?

[TimFox]

One thing to avoid is a conductive path that goes around the toroid (from the bottom, through the hole, around the top, and back to the bottom).
That forms a "shorted turn" that will degrade the transformer.
A screw through the hole, with no "roof" around the toroid, is OK.

[Benta]

A toroid that small would typically be mounted with a blob of thermal glue.

[T3sl4co1l]

Agreed, glue, hot-melt, E6000, silicone, etc. would all be fine, to varying degrees of permanentness.

Tim

[TERRA Operative]

I've seen them in HP/Tek gear fixed in place with two cableties wrapped around each side of the toroid and through 4 holes (two per cabletie, one inside the toroid and one outside)
I've also seen the toroid epoxied (or potted in a small box) to a small carrier PCB with pins attached, then soldered to the main PCB.
You can buy pins that clip onto the side of a PCB then solder them into place, so the legs extend down to be mounted to the main PCB.

The Advantest R6142 and R6144 stand their toroid on its side and use one cabletie through two holes on the PCB, so there are a few options.