magnetic chuck control

wrote:


It's probably more elaborate than that. Electro-matic makes these chuck controllers. http://www.em-chicago.com/chuck_controls.htm
In the dim past, they made the "Neutrofier" electromechanical chuck controllers, which were crazy electromechanical clockwork affairs. I've helped a customer repair the Neutrofier on their Blanchard grinder a couple times. I wish I had taken a photo of it; I can't find one online.
--
Ned Simmons

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wrote:

See patent numbers:
2229104 3401313
--
Ned Simmons

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i have a neutrofier control and if any one is interested, I can take a lot of pictures.
i
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On Sat, 13 Mar 2010 10:42:50 -0600, Ignoramus4212

If the price is right and it happens to match my customer's chuck, they might be interested. My recollection is that the magnet is 240VDC at around 3A. It's on a 30" or 36" Blanchard grinder. Is it a mechanical unit or one of the more modern replacements?
--
Ned Simmons

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Ned, you can email me at ichudov AT algebra DOT com if you have any questions.
Igor
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Ned Simmons wrote:

I have a Netrofier control on one of my bigger surface grinders. You can adjust the dc voltage to the magnet to regulate the amount of holding power to the piece. When you are ready to take the piece off you release it with the control applying ac voltage to the chuck in diminishing pulses of about one second duration. The process takes about 10 seconds. I think I have the manual on the unit in my files. Blanchard grinders use them a lot.
Walker also makes magnetic holding equipment. They are nice units. I have replaced several of the old tube type controls with them and they work flawlessly.
http://walkermagnet.com/products-and-services/products-and-services.html
I think the last one I did was for a 8x 24 inch magnet and the price was about 450.00. They are just a two wire and ground hookup to the magnet and plug into 110 volt outlet. To order you supply the model or size of the magnet and they will supply the right control.
John
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wrote:

The mechanical Neutrofier I worked on has a big rotary switch that sequences a number of polarity reversals and voltage reductions of the DC magnet supply. As far as I know the magnet never sees AC.

Thanks, I'll try to remember that if the Neutrofier becomes uneconomical to repair. The last time they called me the problem was in the commutator under the chuck, not the controller.
--
Ned Simmons

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wrote:

That makes sense and explains the electromechanical stuff. Polarity reversals are by definition AC. This is a (very retro) way to achieve AC excitation that diminishes in magnitude over a period of time.
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On Sat, 13 Mar 2010 23:30:59 -0600, Don Foreman

Is it likely that the simulated low frequency AC is necessary to get that big magnet to change polarity, and that regular 60Hz is fine for a smaller chuck? This chuck is 30 or 36 inches in diameter and probably weighs 1000 to 1500 lbs. I had a chance to ponder its weight when I crawled under it to check the continuity thru the slip rings and windings.
--
Ned Simmons

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nah... there are magnets the size of a bus that work on 60Hz.
LLoyd
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Yep - used a monster monster for semiconductor maga hits.
Semi had iron in it - a big NO NO for most fabs - a bad contaminant.
It had a massive metal core that 'focused in cone shape pole. The pole face was an 300mm wafer diameter.
The real problem- where to use it - without ripping walls down.. :-)
Loading dock. It was put there by a massive Hyster forklift that could tilt its wheels in order to make tighter turns.
Moved the loading dock people to another dock. :-)
Martin
Lloyd E. Sponenburgh wrote:

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wrote:

Yes, if AC excitation voltage is limited to 115VAC. A large inductance may not accept enough current to demagnetize at 115VAC, 60 Hz.
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Very, very dangerous these things.....losing hold power on a magnetic chuck when in use can be very exciting indeed. I am afraid that if I really needed to use one of these things, the circuit would be anything but simple. I would absolutely make certain there would be enough hold time to get the wheel off the work in an emergency. Steve

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