Author Topic: Solenoid sensing  (Read 1231 times)

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Offline lemontreeTopic starter

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Solenoid sensing
« on: December 01, 2009, 09:28:32 PM »
One early lesson I learned was that if you remove the core from an AC solenoid for a few minutes it will burn out.  That is because its inductance is lower with the core out and too much current flows through the coil.  I wonder if anyone has done any practical work on using a solenoid as a position sensor?
If you apply a small amount of ac ripple to a dc solenoid you should be able to estimate the position of the core by measuring the ac current.  By the time you had done all the electronics for that I doubt it would work out cheaper than a servo however.

Offline waltr

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Re: Solenoid sensing
« Reply #1 on: December 02, 2009, 08:32:01 AM »
Yes, I've played with this. There are commercial linear position sensors that use this principle and are called LVDTs. Here are some links:
http://www.rdpe.com/displacement/lvdt/lvdt-principles.htm
http://www.macrosensors.com/lvdt_macro_sensors/lvdt_products/index.html



Offline lemontreeTopic starter

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Re: Solenoid sensing
« Reply #2 on: December 03, 2009, 08:56:59 AM »
Thanks for that.  Have any interesting robots been made that exclusively use solenoids to move around?  A project for myself would be to evolve a solenoid robot design. If ifs and ands were pots and pans.

Offline waltr

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Re: Solenoid sensing
« Reply #3 on: December 03, 2009, 12:55:24 PM »
I think I've seen a robot that used solenoids for movement on Utube.
It was lots of laughs but it worked.

 


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