Electromagnet with 30mA
Electromagnet with 30mA
(OP)
Hi,
I'm a kind of "crazy inventor", and have now certain kind of "break through" invention on my mind
.
I have surfed hours on the web, finding answer what one can get for electromagnet with 30mA and 50-100 turns coil if you can freely select the core material and the shape of core. I have not found the answer. Because the answer is easy to be given for a prfessional, I hope some of you could give it!
"what one can get" equals, more or less to, how big force can be gotten!
Thanks!
Tapio
I'm a kind of "crazy inventor", and have now certain kind of "break through" invention on my mind
I have surfed hours on the web, finding answer what one can get for electromagnet with 30mA and 50-100 turns coil if you can freely select the core material and the shape of core. I have not found the answer. Because the answer is easy to be given for a prfessional, I hope some of you could give it!
"what one can get" equals, more or less to, how big force can be gotten!
Thanks!
Tapio





RE: Electromagnet with 30mA
RE: Electromagnet with 30mA
RE: Electromagnet with 30mA
thread340-141078
thread340-132216
If you are looking for the equation for force across an airgap:
Force (in Newtons) F = B2*A/(2*?0)
where B is the flux density in the airgap (Tesla)
A = area of pole face (or area of airgap in direction perpendicular to flux) (m2)
?0 = permeability of free space (=4*pi*10-7)
i.e. all in SI units
If you assume a typical flux density in the airgap of 1.0T, you can rewrite this equation as:
force/area = 0.4N/mm²
BUT - to get a flux density of 1.0T for an airgap of 1.0mm, rearranging the equation for reluctance of an airgap (given in one of the above threads) to give ampere-turns:
NI = B*g/?0 where g is the airgap (in meters)
= 800 Ampere-turns
Multiply that by 2 (say) to account for reluctance in the rest of the magnetic circuit (>2 if you have another airgap elsewhere) gives 1600Ampere-turns.
I'm afraid you only have 1.5 to 3 A-t from you initial post, so the force you can expect is going to be tiny,
something like less than 1microNewton per mm².
RE: Electromagnet with 30mA
Let's continue this threat.
How about if I'll use a permanent magnet as an anchor? So the actual force cames from permanent magnet, and the electromagnet is only used as a controller?
Is there any, even hypothetical, way to increase the 1microNewton per mm2 with that kind of construction?
Thanks for your previous answers!!!!!
RE: Electromagnet with 30mA
http://www.beikimco.com/appguides/actuators.php
Perhaps as you require only a very small displacement, you could employ a step-down geared system.
RE: Electromagnet with 30mA
try to describe the problem well enough to help finding
a solution.
Plesae read FAQ240-1032
<nbucska@pc33peripherals.com> omit 33 Use subj: ENG-TIPS