Solenoid Problem

On 1 Aug 2004 20:50:23 -0700, Greg put forth the notion that...

It's possible that the insulation on the coil windings is breaking down, and shorting out part of the coil. If so, you may have enough magnetism to operate the solenoid, but not enough to get the full amount of force out of it.

I get 91 ohms reading from the coil which is correct from the manufacturer... Are you saying this could change under pwr-up and loaded conditions?

Is the cutting blade as sharp as it should be? Even a slight loss of edge to the blade could make a big difference in cutting thick material near the limit of the machine. Have you tried a new blade or is it possible to hone the old one?

On 2 Aug 2004 10:08:34 -0700, Greg put forth the notion that...

If that's the resistance you're supposed to be getting, than the problem is somewhere else. Is the material you're cutting any different from previous batches? Is the coil getting full voltage?

Unless there is a shorted turn, a solenoid coil should be as good as new if it still works at all.

There ARE other problems: 1) the laminations in the armature of stator of the solenoid may be shorted together; 2) there may be wear in the bearing surfaces which cause binding.

It is the same material and I tried a brand new blade.....I should say that I am just trying to pierce the material when I engage the blade and not actually cutting the material. Yes the coil is getting the correct voltage (23.7V). I am still looking and trying messing with the linkage cause I realize that any extra resistance from the linkage could take away from the downforce. I can help the blade to get thru the material and it will hold there but can not get to that point by itself. Thanks

Tried new blade and no help....still thinking it may be a linkage problem... confused........check out my earlier post

in article 410f4363$1$ snipped-for-privacy@dingus.crosslink.net, John Gilmer at snipped-for-privacy@crosslink.net wrote on 8/3/04 12:16 AM:

I ran into an interesting problem many years ago with a solenoid that had a shorted turn. I report to the best of my memory.

I was modifying a Rudolph polarimeter to measure orientation normal to the line of sight at a considerable distance. A Faraday rotator conisting of a piece of glass inside the solenoid which, IIRC, ran at 60 Hz. This wobbled the polarization enabling an error signal to be generated. Unfortunately, 60 Hz was within the range where atmospheric turbulence was troublesome.

To get around the atmospherics, I tried running the Faraday cell at 400 Hz. While the cell behaved well at 60 Hz, the shorted turn gave much trouble at

Bill

I wonder if the driving circuitry could be the problem. While the solenoid is rated at 24 V continuous duty, could it be that the circuit is designed to blast it with a much higher pulse when it is first energized?

Greg,

It sounds like you did a good job of looking at the mechanical stuff; you might be on the right track thinking that your problem might not be electrical. One thought is that whatever aligns the solenoid's magnetic bits might be worn such that the armature is now rubbing.

I suppose, in an ideal situation, the armature will be sort of suspended such that it does not impact anything as it moves in and out of the magnetic field. If it does rub, the result will be increased heat of friction and less efficient energy transfer between the magnetic field and the moving stuff. This means the input current will increase, the thing might get hotter and, oh yea, it has less energy to transfer to the cutting head now that it is using that energy to do unwanted things.

If this is happening, it could be that a bushing is worn out and may get automatically replaced when you replace the solenoid. Of course, I can't see the thing, so this may not be relevant advice. But you can see it and judge for yourself.

Good luck,

Ken

Have you make change at your local ambient temperature? Any additionnal degree increase resistance of the coil and thus the current is reduced and the force is reduced accordingly. Measure the resistance of the coil when it is hot and cold. Does your puncher works when at cold?

Martin

"Greg" a écrit dans le message de news: snipped-for-privacy@posting.google.com...