Operating a solenoid at a higher voltage

[parmalee]

I know that operating a solenoid at a voltage higher than it's rating will shorten it's life, but by how much?

Here's the scenario: I'm triggering a small 6v 300mA push-pull solenoid via a MOSFET with a roughly 5ms to 15ms pulse (it varies) and I'm getting better results from a roughly 7.5v supply (or 9v dropped through a diode).

I could probably get it to operate as reliably at 5v or 6v, but with a few more parts and I'm aiming for less real estate.

Is that 7.5v really going to alter that solenoid's lifespan all that significantly, or should I just not worry about it? I mean, no one's life is on the line here, or anything like that.

 

[billvon]

Is that 7.5v really going to alter that solenoid's lifespan all that significantly, or should I just not worry about it? I mean, no one's life is on the line here, or anything like that.

Depends on how hot it gets. Heat is what kills solenoids.

For a simple solution, close it with 7.5V and then hold it closed with 5V.

But for those time durations it may not matter; it won't get hot if you are using it 15ms at a time at a low duty cycle.

 

[parmalee]

Depends on how hot it gets. Heat is what kills solenoids.

For a simple solution, close it with 7.5V and then hold it closed with 5V.

But for those time durations it may not matter; it won't get hot if you are using it 15ms at a time at a low duty cycle.

Thanks. Yeah, it's only going to be triggered by very short pulses, and with at least 500ms between triggering. Actually, I've only been testing it with 5v as opposed to 6v, because I've only got L7805s on hand and 78L06s, but no L7806s.

I'm kind of surprised that I can't get it to trigger reliably at 5v though. With most solenoids, it seems that you can drop the voltage almost by half, or at least 2/3, and still get a response at least.