Rich said:
>My guess is that a $1 MOV would have prevented this glitch.<
Maybe. What I read was that during ground testing, the supply was unregulated,
and went up to around 70 volts, causing the thermostat to arc because the
voltage it was trying to switch was too much - in terms of DV (Direct Voltage -
you really can't have a 'Direct Current Voltage', now, can you?). The MOV
would probably have just burnt out. What is clear (and I think Rich is saying
this, too) that underating switches, thermostats, relay contacts and solid
state switches etc. is a poor idea.
20 odd years ago, VMOS devices were touted as ideal for relay drivers and the
like, but it turned out that they needed VERY fast diode protection compared
with bipolars....
73
Peter G3RZP (I've been away all week, and haven't read all the items, so
there's something I should have responded to, let me know)
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|