Hello everyone i have several dc-ac 2amp ssrs and need to activate 48vdc solenoids, may i proceed and use rectifier bridges with the ssr's to activate the solenoids? Also im not sure how much altern voltage should i apply to obtain 48v approx.
I have no experience with fets whatsoever so wanted to stay with these cheap ac ssr's.
How much current does each solenoid need?
They are rated at 48w so 1 amp I suppose, not considering the inductive surge. Also I observed that when connecting the cables ac produces considerably less electric arc than dc.
not considering the inductive surge.
This is a surge when you turn the inductor off not on.
Inductance slows down the initial rise in current.
Have you got a link to that ssrs you have?
The ssr's model is omron g3mb-202p, 240VAC at 2A
Datasheet:
Where'd you get them? I don't see any availability at Digikey or Mouser. Or Avnet. Or Arrow.
Might regular mechanical relays work here? I have an 8-relay card, 5A/relay, that is controlled via shift registers and daisychainable if you need more than 8.
Ive got several 8 channel ssr boards from sainsmart, available also on ebay.
And well the solenoids may switch at up to 5 times per second so normal relays aren't suitable.
Now im testing them and seem to work just fine, not heating at all. Im just concerned about their reliability, they are made in Japan and working under spec. Maybe the voltage ripple can damage the solenoids? since ive included a full wave rectifier without capacitors, which can slow down the response.
Steinhoff:
Maybe the voltage ripple can damage the solenoids?
No.
What is rather elegant about this arrangement, is that you are completely protected against switch-off surges from the solenoids as firstly, the bridge rectifier immediately before the solenoid is automatically configured to suppress this, and the SSRs switch off at zero current anyway.
The only problem I could see is that if your solenoids are sufficiently responsive to commutate multiple times per second, they may just vibrate with the rectified AC though of course, it is now pulsating at 100/ 120 Hz - double the mains frequency.
Hi Paul, thanks for the feedback, the solenoids perceive a very small vibration but function fast and strongly.
Also we just burnt one resistive fuse, so they also seem a must to keep the ssr safe.