Ledex makes some good ones. I bought 2 from them. Find a supplier on their homepage, if they don't sell directly (I can't remember). Just pick the one you want based on the best operating voltage and current draw for your project. Make sure you know if you're getting push or pull solenoids. They've got good datasheets for determining strength as a function of it's position.
No, it's either on or off. Apply a voltage to it, and it'll move (fast). Take the voltage away, and it stops. Make sure you have a good power supply, cause it'll drain lots of current. Alkaline batteries usually don't work too well.
Um, you can fry a solenoid easily if you don't drive it properly, and each has different specs, you gotta get enough info on them. If it says continous duty, you just drive them at thier rated voltage, if they give a specific duty, you must adhere to that pulse ratio or you solenoid winding will melt and short. heres a good place for surplus solenoids: http://www.allelectronics.com/cgi-bin/category.cgi?category=575&type=store·Solenoids are rated usually for 6,12 or 24 volt the higher the voltage ussually the higher the force. Your going to have problems operating them in a mobile device they typically require many amps to operate, and even the best batteries will not like that kind of load, with the exception of lead acid (SLA brick) and they are heavy as sin.
Post Edited (Paul Baker) : 1/29/2005 9:49:26 PM GMT
And don't forget to use a diode across the coil windings (in opposite polairty as your circuit) or when you remove the power from the coil windings the reverse high voltage coming back from the magnetic field can fry your transistor or whatever you drive the relay coil with. sometimes 12VDC in can be 1200VDC spike coming back out!
Low amps, but enough to fry a transisitor.
Also, make sure that when the solenoid is actuated that it travels it's full throw. I know that some solenoids will burn out if they are actuated and can only pull in (or push out) for part of the total distance that they would move if not connected to the device.
paysonbadboy is correct, though if you use a hexfet, or a similar switching power transistor (like an IGBT) it will contain a flyback protection diode within the transistor itself, the tech doc for the transistor will show whether that particular transistor has one. If you choose a 25% or less duty solenoid, you maybe able to design a switched capacitor configuration that would be more friendly to standard rechargeable batteries (you'll still need to use NiMH, nicads would work, but you will severely reduce the number of times they can be recharged)
Jim McCorison said...
Also, make sure that when the solenoid is actuated that it travels it's full throw. I know that some solenoids will burn out if they are actuated and can only pull in (or push out) for part of the total distance that they would move if not connected to the device.
Jim
Aint that the truth!
One time·I was working on this one walk in freezer.
Instead of turing off the power to the "pump down selenoid"·I just pulled the coil off of the post it went to and that basically shut off the referigerant valve for me.
Finished fixing wheatever I was doing on the freezer and went to place the coil back on the post of the valve. NOPE! The windings burnt through the plastic of the coil assembly!
It's weird but maybe when the magnetic field is concentrated the amps in the circuit·goes down or somthing. Now that we are thinking about it I'll have to measure amps some day with the coil windings on and off the selenoid post.
...One time I was working on this one walk in freezer.
Instead of turing off the power to the "pump down selenoid" I just pulled the coil off of the post it went to and that basically shut off the referigerant valve for me....
Hope the compressor was off or that might be only the start of your problems!
blink13:
I would not try to drive that particular solenoid with 9V since its stated range is 3-6V. The site does not provide enough information to answer you question since it does not provide pull force or throw distance. And the provided part number does not produce any information in search engines or deltrol's website. The only way of knowing what those values are is to buy one, measure its throw distance and get a spring scale like the ones used in high school physics classes. You would pull the scale on the activated solenoid until it pulled the plunger out of its activated position and that is the pull force.
or just go with achilles03's suggestion and get one from www.ledex.com since they provide specs.
blink13
Posts: 65
Comments
www.ledex.com
Hope that helps...
Dave
Dave
bugg
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So many projects, so little time.
Post Edited (Paul Baker) : 1/29/2005 9:49:26 PM GMT
Low amps, but enough to fry a transisitor.
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http://www.paysonarizona.net/
Jim
One time·I was working on this one walk in freezer.
Instead of turing off the power to the "pump down selenoid"·I just pulled the coil off of the post it went to and that basically shut off the referigerant valve for me.
Finished fixing wheatever I was doing on the freezer and went to place the coil back on the post of the valve. NOPE! The windings burnt through the plastic of the coil assembly!
It's weird but maybe when the magnetic field is concentrated the amps in the circuit·goes down or somthing. Now that we are thinking about it I'll have to measure amps some day with the coil windings on and off the selenoid post.
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http://www.paysonarizona.net/
would this one work on 9VDC and be suitable for my needs??
Instead of turing off the power to the "pump down selenoid" I just pulled the coil off of the post it went to and that basically shut off the referigerant valve for me....
Hope the compressor was off or that might be only the start of your problems!
I would not try to drive that particular solenoid with 9V since its stated range is 3-6V. The site does not provide enough information to answer you question since it does not provide pull force or throw distance. And the provided part number does not produce any information in search engines or deltrol's website. The only way of knowing what those values are is to buy one, measure its throw distance and get a spring scale like the ones used in high school physics classes. You would pull the scale on the activated solenoid until it pulled the plunger out of its activated position and that is the pull force.
or just go with achilles03's suggestion and get one from www.ledex.com since they provide specs.