# electromagnet OPENING a door

S

#### Sammy Taylor

Jan 1, 1970
0
Hi,

I'm building a small safe with an electronic strike (i.e., latch). When a
timer activates,
the strike releases. I want the door to pop open, and using a spring is
awkward. I thought a simple electromagnet might work. Can somebody suggest a
geometry.

Cheap strong electromagnets seem to be of the U-shaped variety. Can I use
one
of these and a permanent magnet to repel each other? (I can't use two
permanent magnets because the pre-load on the strike can be enough to
prevent it from opening.)

Thanks for any help.

sammy

R

#### Rich Grise

Jan 1, 1970
0
Hi,

I'm building a small safe with an electronic strike (i.e., latch). When a
timer activates,
the strike releases. I want the door to pop open, and using a spring is
awkward. I thought a simple electromagnet might work. Can somebody suggest a
geometry.

Cheap strong electromagnets seem to be of the U-shaped variety. Can I use
one
of these and a permanent magnet to repel each other?

I can't imagine why not, as long as you can figure out how to trigger it
and everything. Unless you hit it with enough force to make the lid a
lethal weapon, it shouldn't hurt the permanent magnet, as long as it's
really "permanent".

Cheers!
Rich

J

#### Jasen Betts

Jan 1, 1970
0
Hi,

I'm building a small safe with an electronic strike (i.e., latch). When a
timer activates,
the strike releases. I want the door to pop open, and using a spring is
awkward. I thought a simple electromagnet might work. Can somebody suggest a
geometry.

Cheap strong electromagnets seem to be of the U-shaped variety. Can I use
one
of these and a permanent magnet to repel each other?

yes if you can get a magnet with the correct configuration and of the
correct strength, too weak and the electromagnet will attract it, too strong
and it will stick to the electromagnet

(I can't use two
permanent magnets because the pre-load on the strike can be enough to
prevent it from opening.)

here's some other ideas. use the the electromagnet to hold the door shut
while you trigger the strike, and then release it and let the spring open
the door.

use a push-type solenoid to nudge the door open when you trigger the
strike

replace the strike with one with a stronger solenoid, or replace the
solenoid etc...

Use a central locking actuator to operate the latch or to nudge the door.

hmm, thinking automotive, don't some vehicles have electricly opened fuel
flaps?

Bye.
Jasen

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