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Posted by Gunner on March 13, 2006, 5:45 am
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This is a bit embaressing. Sigh..its been a looong time since I needed
to figure this sort of thing out.....Im a board changer/wrench
turner/relay and plc type...
I have an elderly electromagnetic chuck that Ive been sitting on for a
couple years until I found a decent usable 6x8 surface grinder..which
I recently did (Covel), but it has no power supply. Rated 110vts DC.
So I dug out a bridge rectifier, added a power cord, and powered up
the chuck with the output. Chuck does indeed work, but its a smidge
weaker than I think it should be..or would like it to be. Its half
wave DC..so Im only applying a magnetic field half the time, right?
Now if I added a simple capacitor to the output, it should give me a
longer signal time as it fills in the gaps. This should result in a
slightly stronger effective magnetic field. Right?
One that is not forming and collapsing 60 times a second
Assuming Ive not shit in my messkit at this point..what MFD cap should
I use? Cringe.....blush
Current draw is about 1 amp
Clean DC would be nice..but its only a magnetic chuck....
Shrug..
Now the last thing....some electo chucks tend to magnitize over
time..or bleed off the field over a number of seconds.
If I put a maintained On/off/Momentary On toggle switch in...I should
be able to run a momentary bit of 110vAC though the chuck to
demagnitize it, right?
Thanks
Gunner, hanging his head in shame...
"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3
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Posted by Leon on March 13, 2006, 6:00 am
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Gunner wrote:
> This is a bit embaressing. Sigh..its been a looong time since I needed
> to figure this sort of thing out.....Im a board changer/wrench
> turner/relay and plc type...
>
> I have an elderly electromagnetic chuck that Ive been sitting on for a
> couple years until I found a decent usable 6x8 surface grinder..which
> I recently did (Covel), but it has no power supply. Rated 110vts DC.
>
> So I dug out a bridge rectifier, added a power cord, and powered up
> the chuck with the output. Chuck does indeed work, but its a smidge
> weaker than I think it should be..or would like it to be. Its half
> wave DC..so Im only applying a magnetic field half the time, right?
>
> Now if I added a simple capacitor to the output, it should give me a
> longer signal time as it fills in the gaps. This should result in a
> slightly stronger effective magnetic field. Right?
> One that is not forming and collapsing 60 times a second
>
> Assuming Ive not shit in my messkit at this point..what MFD cap should
> I use? Cringe.....blush
>
> Current draw is about 1 amp
>
> Clean DC would be nice..but its only a magnetic chuck....
>
> Shrug..
>
> Now the last thing....some electo chucks tend to magnitize over
> time..or bleed off the field over a number of seconds.
>
> If I put a maintained On/off/Momentary On toggle switch in...I should
> be able to run a momentary bit of 110vAC though the chuck to
> demagnitize it, right?
Yes, you do need a capacitor. Size depends on how much current you are
drawing, it can be calculated (depends on how much ripple you can take)
but something like 5,000 uF per amp is probably about right. Make sure
you get one with the correct voltage rating. 4,700 uF should be fine
with 1 A.
The AC should demagnetise it OK.
Leon
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Posted by Bill Janssen on March 13, 2006, 11:07 am
Please log in for more thread options Gunner wrote:
>This is a bit embaressing. Sigh..its been a looong time since I needed
>to figure this sort of thing out.....Im a board changer/wrench
>turner/relay and plc type...
>
>I have an elderly electromagnetic chuck that Ive been sitting on for a
>couple years until I found a decent usable 6x8 surface grinder..which
>I recently did (Covel), but it has no power supply. Rated 110vts DC.
>
>So I dug out a bridge rectifier, added a power cord, and powered up
>the chuck with the output. Chuck does indeed work, but its a smidge
>weaker than I think it should be..or would like it to be. Its half
>wave DC..so Im only applying a magnetic field half the time, right?
>
>Now if I added a simple capacitor to the output, it should give me a
>longer signal time as it fills in the gaps. This should result in a
>slightly stronger effective magnetic field. Right?
>One that is not forming and collapsing 60 times a second
>
>Assuming Ive not shit in my messkit at this point..what MFD cap should
>I use? Cringe.....blush
>
>Current draw is about 1 amp
>
>Clean DC would be nice..but its only a magnetic chuck....
>
>Shrug..
>
>Now the last thing....some electo chucks tend to magnitize over
>time..or bleed off the field over a number of seconds.
>
>If I put a maintained On/off/Momentary On toggle switch in...I should
>be able to run a momentary bit of 110vAC though the chuck to
>demagnitize it, right?
>
>Thanks
>
>Gunner, hanging his head in shame...
>
>
>"A prudent man foresees the difficulties ahead and prepares for them;
> the simpleton goes blindly on and suffers the consequences."
>- Proverbs 22:3
>
>
The problem with using AC to demagnitize is that when you turn it off
you may turn it off
when the voltage is high and you remagnitize it. You need to slowly
reduce the AC current.
Bill K7NOM
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Posted by Ron Moore on March 13, 2006, 11:10 am
Please log in for more thread options Sounds like a great application for a Solid State Relay. I'll throw one of
those in, too.
Ron
> Gunner wrote:
>>
>>Now the last thing....some electo chucks tend to magnitize over
>>time..or bleed off the field over a number of seconds.
>>
>>If I put a maintained On/off/Momentary On toggle switch in...I should
>>be able to run a momentary bit of 110vAC though the chuck to
>>demagnitize it, right?
>>
>>Thanks
>>
>>Gunner, hanging his head in shame...
>>
>>
>>"A prudent man foresees the difficulties ahead and prepares for them;
>> the simpleton goes blindly on and suffers the consequences." - Proverbs
>> 22:3
>>
> The problem with using AC to demagnitize is that when you turn it off you
> may turn it off
> when the voltage is high and you remagnitize it. You need to slowly reduce
> the AC current.
>
> Bill K7NOM
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Posted by Leo Lichtman on March 13, 2006, 11:23 am
Please log in for more thread options I had a thing like that once that was intended for running portable power
tools. The rectified/boosted power really made portable AC/DC tools run
strong. It was intended to compensate for the drop in a long extension cord.
After you get this thing built, you might try plugging in a couple of power
tools, just for fun. Mine was stolen, and as far as I know they are no
longer made.
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> to figure this sort of thing out.....Im a board changer/wrench
> turner/relay and plc type...
>
> I have an elderly electromagnetic chuck that Ive been sitting on for a
> couple years until I found a decent usable 6x8 surface grinder..which
> I recently did (Covel), but it has no power supply. Rated 110vts DC.
>
> So I dug out a bridge rectifier, added a power cord, and powered up
> the chuck with the output. Chuck does indeed work, but its a smidge
> weaker than I think it should be..or would like it to be. Its half
> wave DC..so Im only applying a magnetic field half the time, right?
>
> Now if I added a simple capacitor to the output, it should give me a
> longer signal time as it fills in the gaps. This should result in a
> slightly stronger effective magnetic field. Right?
> One that is not forming and collapsing 60 times a second
>
> Assuming Ive not shit in my messkit at this point..what MFD cap should
> I use? Cringe.....blush
>
> Current draw is about 1 amp
>
> Clean DC would be nice..but its only a magnetic chuck....
>
> Shrug..
>
> Now the last thing....some electo chucks tend to magnitize over
> time..or bleed off the field over a number of seconds.
>
> If I put a maintained On/off/Momentary On toggle switch in...I should
> be able to run a momentary bit of 110vAC though the chuck to
> demagnitize it, right?