J
John S
- Jan 1, 1970
- 0
No, that wasn't a hack as far as the diodes goes, that is a practical
design in a family of relays, We use large contactors with the dual
coil and diodes in them. You don't see this from the out side world but
they are incased in the encapsulation. Those particular types can have
DC going directly to them. It's just the way they are with obvious
reasons.
The app note is pointing equivalent power dissipation, as you
know relays will pull in at a lower current So I don't see a problem
here.
Why don't you put a few AC types on the bench and test them yourself?
I think you'd be surprised in what you find. Lab testing tells a lot
about what you can do.
The only problem I have found with this practice of using AC on DC is
that some AC units use material that has a high hysteresis and the
AC will help keep this down. They do this in cases where they don't use
the dual coil system. In DC operation, I've seen it over magnetize the
core and cause a little slow release on the contacts. But that may not
be such a big deal in most cases.
Have a good day.
Jamie
I have an Essex contactor which was removed from my old A/C outside
unit. It has a 24VAC 50/60 Hz coil. I can make some measurements on it
if anyone is interested.
John S