[Amps] Crouzet SSR - FAQs

TexasRF at aol.com TexasRF at aol.com
Tue Feb 11 10:44:53 EST 2014

Paul, many thanks for sharing that valuable resource!
After reading the information I can see why there is much more to be  
considered than one would think. The SSR needs to be sized to handle a worst  
case load and that case is not well defined at all.
The heat sinking requirements are far greater than any I have supplied with 
 past projects. In fact, I never considered the need for heat sink compound 
when  mounting a SSR on a .125" thick back panel. Too little thermal mass 
in the panel  and poor thermal coupling to the SSR pretty much tells the 
The other thought brought up by others of a big inductive kick when the  
power supply is turned off was not considered either. When a big KAPOW event  
happens you can be sure that maximum current is flowing through the SSR when 
the  fault trip shuts it off. Then a huge voltage transient causes the SSR 
to fail in  a shorted condition, defeating the whole purpose of a trip 
detector  circuit.
I guess this is what happens when an amateur does the design work; amateur  
Thanks to all for a very enlightening discussion!
Gerald K5GW
In a message dated 2/10/2014 5:47:13 P.M. Pacific Standard Time,  
elespe at lisco.com writes:

There is  a wealth of information here worthy of reading which may further  
understanding of solid state relays, the application, what they can and  
can't do and the myth of zero turn on related to inductive  loads


Paul K0UYA  

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