I have a new solenoid rated 110vac that gets too hot. I have tried it on a variac and can get magnet working at 55 volts or so and it stays cooler. Can I use a resistor and capacitor voltage divider on ac to get near 55 vac to this ?

 

Instead of a resistor, I would experiment with an appropriate incandescent light bulb in series with the solenoid. The solenoid will receive a higher initial turn on voltage and then the current will fall as the bulb heats up.

 

...Or source a solenoid with a higher voltage rating. Series solutions usually don't work that well. i.e. resistor, bulb, etc.

 

...Or source a solenoid with a higher voltage rating. Series solutions usually don't work that well. i.e. resistor, bulb, etc.

Ideally I could get a 220vac since this one is 110 and works best at half that, it's worth a try since I got it cheap online and it's easily returned.

 

Ideally I could get a 220vac since this one is 110 and works best at half that, it's worth a try since I got it cheap online and it's easily returned.

That doesn’t make sense. The solenoid was designed to work at the specific operating voltage.

 

That doesn’t make sense. The solenoid was designed to work at the specific operating voltage.

But, by the sound of it, not at a 100% duty cycle.

 

But, by the sound of it, not at a 100% duty cycle.

Certainly there are quite a few solenoids sold that are intended only for short on times/intermittent duty operation. They work well to operate an unlatch function, but they burn up when serving to hold a latch locked.

 

What is the function of the solenoid ?
If the armature is not shifting completely over, it is liable to overheat!, on an AC version.

 

I have a new solenoid rated 110vac that gets too hot. I have tried it on a variac and can get magnet working at 55 volts or so and it stays cooler. Can I use a resistor and capacitor voltage divider on ac to get near 55 vac to this ?

If you are operating the AC solenoid within its rated voltage/frequency , it shouldn't get hot.
Can you post the part number?

 

You could reduce the average voltage with a TRIAC type AC motor speed controller, with the possible problem of that causing a buzzing noise from the inductor.

 

Do you have a link to the solenoid? As mentioned some are designed for continuous duty and some intermittent duty. The idea being to use the correct solenoid for your application. Trying to reduce the voltage on a 110 or 120 VAC solenoid is not a good idea. What mains frequency is the solenoid designed for and what mains frequency are you applying as in 50 / 60 Hz?

Ron

 

There is the fact that after a solenoid moves, every bit of the applied power is converted to heat. That means that even a solenoid working within it's design intent will certainly get quite hot eventually. VxI/ mS=rise in temperature because Q=mS(Tf-Ti)

 

There is the fact that after a solenoid moves, every bit of the applied power is converted to heat. That means that even a solenoid working within it's design intent will certainly get quite hot eventually. VxI/ mS=rise in temperature because Q=mS(Tf-Ti)

Yes, and when it heats up enough the solenoid coil takes on a newlook.



Note this was a perfectly good 24 VAC solenoid right till it was used to replace a 24 VDC solenoid.

Not really thread related but amusing just the same. Always choose the right solenoid for the application.

Ron

 

All the projects I was involved in I always made a point of using DC magnetic devices.
Much less trouble. !
If they don't shift over, at least they don't burn out !

 

I once had to upgrade the power supplies for a project that utilized 24 volt DC solenoid valves because the first 15 of the 48 valves were on hand. So there were quite a few 48 volt 15 amp supplies required. And because most of the valves were active most of the time that was quite a bit of heat. It would have been vastly cheaper to have used 120 volt AC valves. BUT nobody asked me until it was built.

 

Hi everyone,
here is the solenoid,I chose this one because it said continuous duty. The use of it is to hold open lp gas and stop it if fan loses power. I could use a 12v dc since my system uses dc also.

 

What is the function of the solenoid ?
If the armature is not shifting completely over, it is liable to overheat!, on an AC version.

The solenoid is meant to hold open gas line while a forced air forge is operating and stop gas if fan blows fuse or power goes out,I want to add this to my system for safety

 

I could use a 12v dc since my system uses dc also.

With a DC relay you can use a hit and hold circuit which momentarily applies full voltage to pull in the solenoid and then goes to a lower voltage just sufficient to hold it open.
This can be efficiently done by varying the duty-cycle of a PWM signal to the solenoid coil.

 

Ideally I could get a 220vac since this one is 110 and works best at half that, it's worth a try since I got it cheap online and it's easily returned.

And, perhaps, herein lies the problem.

 

OK, and the power consumption is claimed to be "5.5 VA" which tells me that after the valve opens all of that is producing heat, about 5.5 watts worth. Certainly that will lead to a temperature rise. Certainly a valid safety concern. If a 220 volt AC valve would open reliably with 120 volts, that would be a really simple alternative.
Is that the actual valve that overheats?? I do not see any brand name, and that is a cause for concern that the producers choose to be unknown. It might be that there is simply not enough copper in the solenoid coil. And possibly not enough iron in the magnetic path.
The very simple scheme to reduce the holding power use would be to put a 120 volt incandescent light bulb i series with the coil, which will drop the current after the initial turn-on surge, and serve as an indicator that the gas is "ON".