torroidal transformer vendor

[richard mullens]

John Larkin wrote:

Hi,

Can anybody recommend a good source for a custom torroidal power
transformer? It will be roughly 50 VA; we need prototypes fast, and
maybe 100 per year after that.

There are about 200 suppliers listed in the EEM for torroids, and I
guess we'll spam lots of them with our spec, but I just wondered if
anybody has a vendor they especially like.

Maybe not what you need, but how about one of those switched mode "transformers" used for powering 12V lamps from the mains.

In our local DIY shop (B&Q) they have 70W and up to 200W from between Ł10 & Ł20.

 

[John Larkin]

On Sat, 12 Feb 2005 03:55:43 GMT, richard mullens
<mullensdeletethis@ntlworld.com> wrote:

John Larkin wrote:
Hi,

Can anybody recommend a good source for a custom torroidal power
transformer? It will be roughly 50 VA; we need prototypes fast, and
maybe 100 per year after that.

There are about 200 suppliers listed in the EEM for torroids, and I
guess we'll spam lots of them with our spec, but I just wondered if
anybody has a vendor they especially like.


Maybe not what you need, but how about one of those switched mode "transformers" used for powering 12V lamps from the mains.

The output of my box is going straight into an NMR probe inside a
megabuck superconductive magnet, where they're looking for some very
small RF signals; they even cool the pickup coils and preamps to 40K
to reduce the noise floor. Switchers aren't allowed anywhere near this
stuff.

Besides, I have a high ratio of peak to average power output, and good
old fashioned iron and electrolytics are more economical here.

John

 

[Ken Smith]

In article <4d3b7a0997tonyw@ledelec.demon.co.uk>,
Tony Williams <tonyw@ledelec.demon.co.uk> wrote:
[...]

However, I think there is a polyswitch type of device
that opens at a set temperature, but which then only
requires a trickle current to keep it open. Removal
of the supply is required to re-set it.

I think the thing you are thinking about is actually ceramic. The
polyswitch devices don't seem to be any good at higher voltages. They
have the advantage of going open slowly enough that there is no inductive
spike to worry about.


--
--
kensmith@rahul.net forging knowledge

 

[Tony Williams]

In article <cuoill$skr$1@blue.rahul.net>,
Ken Smith <kensmith@green.rahul.net> wrote:

[I think there is a polyswitch type of device]

I think the thing you are thinking about is actually ceramic.
The polyswitch devices don't seem to be any good at higher
voltages. They have the advantage of going open slowly enough
that there is no inductive spike to worry about.

Perhaps a PTC type of device, with a sharp response
at the required temperature. The sort of thing that
is used to protect motor windings.

--
Tony Williams.