Hi Chris,
Yes, maybe try a homemade filter. I would try something like in the
attachment...
Build yourselfe a current transformer and measure RF common mode
currents in the supply line of the power supply. This can be done with a
clamp ferrite which has a secondary winding and a 1 Ohm resistor. You
can then measure the current with the scope, of course it is decoupled
then. The common mode chokes may already help to lower such currents.
Maybe even simple clamp ferrites on the supply cable can help if these
is no other ground connection.
Of course the ripple voltage of the DC voltage should be as small as
possible. A few 1000 uF near the load may help too...
73, Stefan
Am 07.06.2017 21:12, schrieb Lawrence Galea:
Hi Chris,
Did you Try capacitors across the supply lines right at the output
connectors and also from both + and - to earth?
Did you try the same at the mains input with suitable voltage rating?
Regards
Lawrence
On 6/6/17, Chris Wilson<[email protected]> wrote:
Hello LF'ers,
I have had a few issues with my lovely old Farnell H60/50 linear
bench power supply. It'll do 60V @ 50A but I suspect it's last couple
of uncontrolled output voltage failures may have been caused by RF
getting into it, maybe up the output leads, maybe elsewhere. The
manual makes mention of using caps of "a suitable value" across the
output, or each output pin to ground, when used to power "transient
loads" ; it's far from clear what's meant. The -ve floats relative to
chassis ground. What do people recommend as a means of stopping RF
getting in via the + and - output leads please?
It has SCR control on the transformers primary to keep the voltage
drop across the huge pass transistor tunnel down to around 8V, this
seems to go haywire at random times when powering my TX, and the
2N3055's don't like 103V into them. Worst case scenario should be
73V, but I am pretty sure SCR control fails and the secondary rises
to its full potential. Thanks.
--
Best regards,
Chris mailto:[email protected]
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