driving solenoids with a solid state relay
driving solenoids with a solid state relay
(OP)
I need to pulse a pair of 12vDC solenoids at about 500 strokes per minute. I can use a 555 timer to drive a solid state relay but am concerned that voltage spikes coming back from the solenoids will damage the SSR. The solenoids draw 4amps and my SSR is rated for 10A. Are simple diodes enough the protect the SSR? Any advice greatly appreciated.
Thanks
linacman
Thanks
linacman





RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
Ensure yours is of a transistor type.
RE: driving solenoids with a solid state relay
Maximum voltage across diode is 12 volt.
Current and voltage are under ideal conditions and generous safety factors should be used when selecting diode.
Diode will increase release time of solenoid. To decrease release time, you can
Add resistor in series with diode.-Increases voltage across solenoid and SSR.
Use zener or transient suppression diode instead of diode.-Increases voltage across solenoid and SSR.
The diode is operating at 500 hertz. This should not be a problem for the diode, but should be checked.
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
To xxyz:
My SSR is one which runs on DC voltages. There are not many available but I found one.
To CarlPugh:
I'm not sure why the diode will change the release time of the solenoid. It will drop the switching voltage by a half a volt. The intent is to block reverse voltages from the inductors. Also, the switching speed I mentioned was 500 time per minute (~8 Hz. rather than 500 Hz.)
To OperaHouse:
I've only got 12 vDC available. I ran the solenoids with a conventional relay for a while (really toasted the contacts) switching at 500 per minute. So really my only concern is the protection of the SSR.
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
Note to OperaHouse: Thanks for your suggestion. I checked the SSR specs and it is described as a "MOSFET Output" device, so I don't think I'll need to change (unless I blow them up and am forced to buy something else.
regards
linacman
RE: driving solenoids with a solid state relay
Eaton hydraulics has many notes on protecting electronics hooked to coils, if you can maneuver around their web site.
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
RE: driving solenoids with a solid state relay
I have a system working now, although I think I'll need to add two more solenoids to provide enough power to pull what I need to move. It ran for a good long test without damage to anything.
Note to buzzp:
As ou mention in your first post, I found navigating the Eaton site difficult and gave up after a while. Thanks
linacman
RE: driving solenoids with a solid state relay