• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Need Help! Build Electromagnetic Chuck Controller

Status
Not open for further replies.

parametric.ms

New Member
Hi guys,

I'm newbie on this forum, and looks the right place to solve my problem

I have a magnetic table that use on surface grinder machine but I lost the controller. The table specification 100VDC 0.85A.
I've try to build the circuit using variac transformer and diode bridge just to make a variable DC voltage. But I have a major problem when I put some part on the table for long period, my parts become a strong magnetic. its predictable cos my material characteristics (ferromagnetic material).

That I'd like to ask you, how to demagnetizing table and that parts on my controller? I mean to dump residual magnetic field. What kind of circuit should I build?

Thanks for your kind help and attention
(sorry for my bad english)

Regards,
Andre
 

Sceadwian

Banned
You need a deguassing coil, which is nothing more than an electro magnet that is run from AC instead of DC, you slowly pass the object to be gaussed through the coil a few times and it should remove some to most of the static magnetic field from any 'soft' materials. To avoid building up too much of one particular pole on the table/things on the table periodically reverse the polarity of the table.
 

parametric.ms

New Member
How do I remove my parts if they sticky to the table?

I saw many brand of electromagnetic chuck controller, they offer demagnetize capability in one controller. I still curious what kind of circuit inside controller that can demag the parts? How if I put AC line to the coil? Is it works to demag my table?
 

Mr RB

Well-Known Member
The tables are specced at DC, not pulsating DC (which you are using). Pure DC will have less magnetising effect. Have you considered putting a big capacitor after the bridge rectifier to make it close to proper DC?

And with a switch you could even run the coil on AC for a short period after the machining operation to demag the parts?
 

Sceadwian

Banned
I'd be a little wary using AC on a DC rated electro magnet. The core of the coil will behave... drastically different at AC.
 
Last edited:

parametric.ms

New Member
let say, DC to magnetized and AC to demagnetized.
could you give me a simple connection for my controller?

Variac Transformer --> Rectifier Bridge --> Capacitor --> Coil
(maybe need timer to shoot AC line to dump residual EMF and turn of controller )

If I should put AC line to demag my table and parts, the question is, for how long should I put AC line to the coil? how many voltage and current?

Regards
 

Sceadwian

Banned
Just skip the rectifier bridge, and start the variac up slowly, be wary of any over heating that may occur.

Also what MR RB is saying is that the magnetization is from improper filtering, in other words use bigger capacitors and the problem may go away, or at least be less.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top