To:     PICLIST@MITVMA.MIT.EDU
        cc:
        Subject:        Re: [EE]:  Speeding up a relay - zero crossing detection

Roman sez:


>The main current should always be through the NO
contacts so the break occurs under spring tension
which is highest when the relay is closed and the
break will be very quick.

I think this is the arrangement I am using. There are some safety reasons
(which are too complex to go through here) that I need the main current in
the NO contact, so this is lucky.


>Have you considered using the NO contacts for the
major current, or maybe using two relays if you
need a changover effect which is how some high
current systems work?
-Roman

I haven't considered two relays yet, nor Triacs in parallel with relay
contacts.  This might be a way to control this current precisely without a
big triac heat sink, turn off the relay contacts whenever then turn off
the triac precisely.  But I will consider these excessively complex
solutions after exploiring simple ones.

A 5.6Kohm resistor in series with the catch diode gave me a response about
like the 33V zener.  I am going to try a 51V zener I just happen to have
laying around and see how that works.

--Lawrence


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