Drop voltage for solenoid - Need help with obvious

[Tom Jenkins]

Actually the resistor in series might get you in trouble. The solenoid is an inductor, not a resistor, and therefore the current/voltage relationship is different. Like a motor, the solenoid pull is dependent on current, not voltage. And, if you look at the specs, you will see that the operating current requirement is different than the holding current. I'd check this out before I get too far into this.

 

[keithkyll]

Agreed. That's why I said you might need a capacitor across the resistor. The cap will give it a "kick-start".

 

[Matthew12345678]

I would also just use a relay to get the job done until the proper parts come in.. But i would repair it with the correct part as soon as it comes in to me relays are just another point of failure down the road....

 

[g.mccormick]

Everyone who keeps saying use relay, I don't have 12VDC to begin with, so an interposing relay is not going to help any.

 

[Matthew12345678]

I do not think any of us knew that.. Do you have and extra power supply so you can turn the voltage down and connect your commons?

 

[boneless]

If by any chance you have to open multiple solenoids at once, you could put two in series.

 

[JeremyM]

If by any chance you have to open multiple solenoids at once, you could put two in series.

lol

 

[Jeff23spl]

Actually the resistor in series might get you in trouble. The solenoid is an inductor, not a resistor, and therefore the current/voltage relationship is different. Like a motor, the solenoid pull is dependent on current, not voltage. And, if you look at the specs, you will see that the operating current requirement is different than the holding current. I'd check this out before I get too far into this.

Exact. The solenoid will see a lot less than 12v at time of inrush and may not get enough magnetic power to move. It will probably remain in a ''half closed'' state and burns...
Adding the capacitor to by pass the resistor on the pulse would help.
I would choost a 10w resistor instead to keep room.

This would be nice for an electronic class room but for an industrial process, it is not a good solution. Resistors and other small electronic parts aren't really welcome in the field.
First there isn't much support or terminal connection for them, so the final result won't be visually nice.
Second, This isn't usual so if someone else play around it, it will have a hard time to figure it out.
Third If power supply or valve get replaced, it won't come with a new resistor so good chances that it will be discarted and 12v valve connected to 24 directly....

Unless you are the only one playing with it and you plan to live forever, if you do it make sure to comment it on the drawings etc...

 

[boneless]

lol

I seem to remember some of the valves that are delivered by our burner manufacturer are wired in series. Those were 115 VAC, no DC, but it should work as well?

Temporarily at least..