Crydom Solid State Relay | AEM
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Last seen: 1 month 2 weeks ago
Joined: 02/09/2017 - 17:23
Crydom Solid State Relay


Planning to replace the mechanical relays with Crydom Solid State Relays 

Model D1D40   40 amps, 100 VDC rated.

Looks like a protective diode for inductive loads is needed, as well as a fast blow fuse.


Does anybody have any experience using the Crydom SSRs?

Last seen: 4 weeks 11 hours ago
Joined: 02/16/2016 - 17:53
I have been using Crydom SSR

I have been using Crydom SSR's since the series 1 ECU's. They work great with AEM's specially if youre are using any outputs without Flyback protection since crydoms have them bult in. if you look at the schematic that comes with the D1d40's you will notice that the protective diode is built in. The only time I have used a protective diode is with my big cooling fans that pull close to 30 amps, when they turn on and off I do not want to overheat the built in diode, Other than that I have never used an external diode and never had issues.

If using the Crydom with a constant load I recomend mounting them on aluminum with heat sink compund to dissipate heat and they will last forever.

Kurt's picture
Last seen: 1 week 2 days ago
Joined: 06/04/2014 - 17:17
I'm using a Crydom SSR for my

I'm using a Crydom SSR for my fuel pumps and have wired them in for rad fans.  You can set frequency to 500Hz and you do need a high amp diode accross the inductive load or you'll get high frequency noise over the power lines.  The diodes depicted 2nd diagram do not serve as a flyback diode.