Coil needed

[WheatonDavid]

I'm working on a project that requires a solenoid type coil that runs on 12 volts A/C. I need a coil design that will have a 2" stroke with around 6-8 oz. of force. It will be energized for periods of 10-12 hours. So the duty cycle is 100%

Could anyone give me some ideas what I would need it terms of magnet wire gauge, number of turns, and bobbin size? I need about a 3/8" O.D. plunger. Also I'm guessing that I will need a bridge/diode of some sort to convert the A/C to D/C?

Many thanks!

David

 

[analogkid2digitalman]

Anything avialable off-the-shelf? Much easier than trying to calculate, build, test, and reiterate until success is achieved. Probably safer too, especially running at 100% duty cycle.

Wheels within wheels / In a spiral array
A pattern so grand / And complex
Time after time / We lose sight of the way
Our causes can't see / Their effects.

 

[cbarn24050]

Hi, first you have to decide if you want an ac coil or a dc coil.

 

[OperaHouse]

12V AC seems like an odd voltage. I can understand the urge to use an available voltage and to keep things simple. Still, driving a solenoid with a fixed voltage is a waste of energy. You can get a lot more pull by driving a DC coil hard and then reducing the current after the core pulls in. This can be done with a PWM coil driver or as simple as a capacitor and resistor. DC coils are much easier to find.

 

[WheatonDavid]

In response to questions. I am going to use 12 volts A/C. I want to keep the wiring and circuit simple so I don't think I want to get involved with driving the coil hard then backing off on the current.

Thanks to everyone that has replied so far. Maybe what I want to do is not possible? I have not been able to source a coil off the shelf. Does anyone know where I might look?

David

 

[MikeHalloran]

Two inches is a HUGE stroke for a solenoid.

If you really need 6..8oz when the solenoid is at its weakest, just off the top of my head I'm guessing the force when it's seated will amount to hundreds of pounds, and the power consumption will be in kilowatts.

You really should take a look at the door lock motors used in automobiles.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[ScottyUK]

I agree Mike, 2" is a long stroke for a solenoid. Depending on the physical space requirements, it might be possible to use a solenoid with a shorter stroke coupled to a lever to give the increased stroke. The force requirements are quite small, so this could be a practical solution.



----------------------------------

If we learn from our mistakes,
I'm getting a great education!

 

[nbucska]

if speed is not critical, use motor with leadscrew or rack and pinion etc.


<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032