Electromagnet to actuate a permanent magnet
Electromagnet to actuate a permanent magnet
(OP)
First, I realize that magnetism does not conform easily to simple, exact, equation-driven answers, but I only need a ball-park.
I have a design for something in my head, somewhat a kin to a human heart. It will need to pump air or liquid. Not much, and a little less pressure than a siphon or bloodpressure cuff. It will be of a similar design of a siphon bulb. My current plan is to mount the bulb, with a permanent magnet attached, then to use an electromagnet to 'squeeze' and then 'release' the bulb. The magnet is 1in by 1in sq, and claims to have a 80lb hold capacity. If flexing turns out to be a problem I can also use an array of smaller magnets along the surface.
My question is this:
What kind of electromagnet is best? How big? and what kind of electricity requirement to make this happen? I can overpower and compensate with distance or voltage, but it cannot be underpowered or sluggish. It only needs to move the mag about 1.5 in., but it must make decisive, quick pumps, and it needs to be able to get near 2 per second.
I have a design for something in my head, somewhat a kin to a human heart. It will need to pump air or liquid. Not much, and a little less pressure than a siphon or bloodpressure cuff. It will be of a similar design of a siphon bulb. My current plan is to mount the bulb, with a permanent magnet attached, then to use an electromagnet to 'squeeze' and then 'release' the bulb. The magnet is 1in by 1in sq, and claims to have a 80lb hold capacity. If flexing turns out to be a problem I can also use an array of smaller magnets along the surface.
My question is this:
What kind of electromagnet is best? How big? and what kind of electricity requirement to make this happen? I can overpower and compensate with distance or voltage, but it cannot be underpowered or sluggish. It only needs to move the mag about 1.5 in., but it must make decisive, quick pumps, and it needs to be able to get near 2 per second.





RE: Electromagnet to actuate a permanent magnet
The electromagnet current, voltage, size and more, are a function of the design, distance, forces, cycle time etc,.
The correct way is to do static and dynamic analysis analytically or/and using FEA. You can do trial and error testings with off the shelf electromagnets but it may be time consuming, expensive and no guaranties.
RE: Electromagnet to actuate a permanent magnet
I looked at using an electromagnet at first but the size is too large. The device I'm working on needs to be around 1lb.
So for what your asking - force at 1.5inches - you're going to need an enormous electromagnet. If you want push and pull action then using a permanent magnet attached to the bulb,
with an electromagnet - from some distance - actuating the permanent magnet, .... then I would look at decreasing the 1.5inch distance. But the idea sounds interesting. Linear motors made like this require little maintenance, but unfortunately have short strokes.
RE: Electromagnet to actuate a permanent magnet
using the bulb, I think, is about half stupid. I can accomplish it better I think, with a diaphram. It will give me more flexibility in my design as I will be able to increase diameter and therefore reduce required throw, and still move the same amount of air.
I am BTW only trying to move air... very little air at that. (At an extremely high estimate:5 cu in)
If you were able to generate a couple lbs at .5 inch, that would probably be enough. When you say 'enormous' electromagnet, just how big we talkin'? I have basically no size, weight limit. (other than smaller than a breadbox) If I can keep it around the size of a spindle of CD's that'd be fine.
Oh, and I need it to be basically silent. did the motor thing, too much noise.
RE: Electromagnet to actuate a permanent magnet