Deane Williams wrote in
:

I set up a thermostat in my garage that comes on at 80 degrees F. and
sends a 6 VDC battery voltage to control a 120 VAC solid state relay
which powers up the vent fan. The fans always quit within 2 months to
a year with no obvious defects. These are inexpensive 20 inch box fans
with induction motors. I have tried several brands and styles of fans.
The latest was a Home Depot unit that only lasted 2 months.
Does anyone know of a reason why I can't run an induction motor
from a SS relay? What is killing the fans? I have taken two apart
and there is no smoke smell, no visible damage and if there is a
capacitor it tests OK.
Thanks for any ideas. I am going to switch over to a mechanical relay.

Dean


So you blew some fans. But what about the SSR? Is it suited for diving
these motors? Some properties are as important as properties of a
mechanical relay and even with the right specs it may be defective.

Then, what about the signal diving the SSR? If it comes from a mechanical
switch, the contactbounce can damage or destroy the SSR which in turn can
blow the motor(s). SSRs like to be driven by clean signals and tend to be
much more unforgiving them their mechanical couterparts.

petrus bitbyter