Re: Transformer Soft Start

I have used a large bare transformer to run a hot wire cutter and I
never get a thud on start up.

I have another PSU with large output caps and I do. These do have a
large inrush current. Surely the whole thing about inductors is that
they resist current surges due to inductance.

Anyway on my CNC PSU which is 26v amd 15amps I use a softstart
circuit that charges the output caps through a resister and once thay
are charged that triggers a relay to short circuit the resister. It
is not ideal as it will not start with a load but it does not thud or
cause any other problems.

a friend did the same thing and when testing without the soft start
it really cracked on start up.

MHO

Graham