Replacement power transformers for 1U rack devices

[pvision]

I am replacing transformers on a few bits of American equipment that don't have 110 / 220 voltage switching. Typical examples are dbx 163X, 160X, etc. Usually the transformers bolt to the chassis and have flying leads

I can find transformers with solder connections but they're all  but marginal for use in a 1U rack. Any suggestions for suppliers of transformers with flying leads? Or for transformers that will fit nicely into 1U?

Typical transformers are 15-0-15 up to 24-0-24 VAC and about 6-12 VA. Most bolt to the side panel so length & height are not particularly restricted but width has to be < 42 mm + clearance - say 38-40 mm?

I normally buy at Farnell but they don't seem to have any transformers with flying leads

Toroids would be great in theory but mounting would be a problem

Nick Froome

 

[mjrippe]

Can you fit a torroid in there?  Perhaps mounted to the bottom of the chassis rather than the side.  They tend to have flying leads 

 

[pvision]

Problem with toroids in a 1U box is that it would be a re-engineering task every time. I'd like to avoid that. An example would be a case with a fixed base. To fit a toroid I'd need to disassemble the whole unit, drill the base, dimple it so the mounting bolt wouldn't foul the item racked below it, then reassemble the whole thing.

Much easier to find a transformer in a similar form factor

Nick Froome

 

[Whoops]

I did the same job to my DBX 1u rack machines some years ago.

I used small toroids most of the time. If not I use EI transformers, the flying leads can be just wires you solder to the solder lugs simple as that,

Solder wires to this transformers:

http://uk.farnell.com/pro-power/ctfc12-15/transformer-12va-2-x-15v/dp/1780845

http://uk.farnell.com/pro-power/ctfc12-24/transformer-12va-2-x-24v/dp/1780847

 

[johnheath]

Don-audio from Germany have a wide range of toroids with a number of different primarys and secondarys and they are very fine.

I use them on a regular basis.

https://www.don-audio.com/toroid-toroidal-audio-transformers-power-trafos

Best regards

/John

 

[mjrippe]

If the torroid is small enough (you mention 6-12VA - pretty small) a bit of double sided tape may be all that is required to hold it in place.

 

[zephyrmic]

If the torroid is small enough (you mention 6-12VA - pretty small) a bit of double sided tape may be all that is required to hold it in place.

Or maybe some hot glue would be a good solution - a few dobs around the transformer bottom where it will sit on the case.
Kindest regards,
zephyrmic

 

[Whoops]

Don-audio from Germany have a wide range of toroids with a number of different primarys and secondarys and they are very fine.

I use them on a regular basis.

https://www.don-audio.com/toroid-toroidal-audio-transformers-power-trafos

Best regards

/John

Toroids are easy, Farnel has a vast offer and fast shipping.

 

[Rob Flinn]

Or maybe some hot glue would be a good solution - a few dobs around the transformer bottom where it will sit on the case.
Kindest regards,
zephyrmic

Not sure I'd use hot melt glue to hold a transformer in place, since the transformer is probably likely to heat up a bit & melt the glue.........

 

[pvision]

I love hot glue but not when used to hold a transformer in place. Too risky

There's a tiny ferrite ring in the power supply cable in the Behringer ADA8000. It's held in with hot glue. I've had two where it's come adrift and is rattling round inside

I've used the ProPower trafos from Farnell but the 12 VA one is 45 mm which won't fit in 1U

What's an EI transformer?

I'll look at toroids at Farnell

Nick Froome

 

[radardoug]

Toroids are the way to go. If you have the room, make an Lbracket out of aluminium extrusion which can bolt to the side wall and you can put the bolt through the toroid on the other leg of the L. Simple! Dont let the bolt short through the chassis at top and bottom, thats a nono.

 

[Humner]

If you can place the toroid in a corner then you could drill 2 small holes at the back and side to feed zip ties to hold the toroid at 2 points. That should be secure enough, you can then apply a double sided foam tape to keep it still(the zip ties do most of the holding).

 

[Rob Flinn]

What's an EI transformer?

It's a normal transformer.  The laminations are made out of E & I shaped pieces of metal

 

[pvision]

I had a look for 15 VA toroids for a UREI 7110. They're all too big - about 64 mm diameter and the space is 45 mm max

I have found this but the output pins will require a bit of butchery to fit a 1U case

http://www.mouser.com/ds/2/177/186-187-948805.pdf

Nick Froome

 

[moamps]

I am replacing transformers on a few bits of American equipment that don't have 110 / 220 voltage switching...

I have somewhere used, working transformers (primary switched for 110-220) , one for 160x and one for 166. If you need them, they are  yours. You have to pay only shipping to UK. PM me if you are interested.