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Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
radiotech wrote ...
If you are using AC, i.e. an AC relay coil, it will just buzz on contact with steel unless it has a shading pole piece on the end. This appears as a heavy copper slug on one part of the of the pole.
If you try DC on a 'slugged' relay, it will delay the release time.
That is how dial telephones knew how to let the number pulses through, and set themselves up for the next digit, when the dial was released.
You said 0.05- 0.1 Amps. The magnetic force wil depend on amp-turns of the coil. For a fixed voltage, this makes the distance between the electromagnet and the workpiece to be attracted, dependent on the conductivity of the coil winding.
I do see a piece of copper on the AC coil, but im not going to use an electromagnet. Instead ill use a micro servo, i can then control the degrees holding and letting go, without reluctance and remanance and what ever else would complicate things.
Registered Member #1667
Joined: Sat Aug 30 2008, 09:57PM
Location:
Posts: 374
Forty wrote ...
you could even use a permanent magnet, moved towards or away from a non-magntic spacer by a small motor or solenoid. kinda like how the hand lifters for sheet metal work.
I like the rotary version, just get an iron yoke, a NdFeB magnet and a small hobby servo.
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need a simple electromagnet 100mA to pick up small things.
