Electromagnet Design Help Required

1. Apr 29, 2012

RandomCritter

G’day everyone

I need some direction / advice in the area of electromagnet design.

Application and restrictions:

DC supply

Push down and hold with 100N of force
Pull up with 100N of force and hold with 1,000N of force (or pull up and hold with 1,000N of force)

Stroke length: 10mm – rod needs to travel this distance in less than 1 millisecond

The rod needs to travel the 10mm in one direction in less than 1 millisecond

So, at a frequency of approx. 200 times a second, the following could be assumed:
Push down force of 100N for 1 millisecond
Pull up force of 100N for 1 millisecond
Hold force of 1000N for 3 milliseconds

The air gap at each end of stroke will be 0.5mm

This will operate for weeks at a time so continuous duty is required

Rod weight: 50g

The rod being moved up and down needs to fit inside a 6mm bore, above the bore it can be larger if needed but isn’t preferred.

The choice of rod material is between stainless steel and titanium.

An optional permanent magnet could be fitted to the end of the rod if this would prove beneficial (shown fitted in the below drawing as the tiled section).

The only size restrictions are as per the drawing below of dia. 25mm at base for 30mm. Above this there are no size restrictions.

The temperature of the dia. 25 x 30 section at the base is approx. 80 deg. C, whilst the remaining section will have air passing by and a temperature of approx. 50 deg. C could be assumed. Obviously lower currents are preferred.

What changes would need to be made to the above to make it more suitable to the application?

What size wire would be required?

How many turns and length would be required?

What current would be required?

Should the core of the push electromagnet be made from a thicker material (shown below is approx. 1mm wall thickness)?

Given the stroke length of 10mm, in the below design, would the air gap be considerably less than the 10mm?

Is there a considerable disadvantage to having the two ends of the electromagnets so close together?

Is there any advantage of having a permanent magnet at the end of the rod?

http://www.flickr.com/photos/77831671@N08/7124597799/in/photostream

http://www.flickr.com/photos/77831671@N08/7124597799/in/photostream

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