We've tried it ourselves, and these powerful magnets won't even pick up a single paperclip in the OFF position.
http://www.kjmagnetics.com/blog.asp?p=magswitch&utm_source=K%26J+Magnetics+Newsletter&utm_campaign=a0e7a44399-2015_05_May_Newsletter&utm_medium=email&utm_term=0_73e0031e12-a0e7a44399-244051313 (http://www.kjmagnetics.com/blog.asp?p=magswitch&utm_source=K%26J+Magnetics+Newsletter&utm_campaign=a0e7a44399-2015_05_May_Newsletter&utm_medium=email&utm_term=0_73e0031e12-a0e7a44399-244051313)
Video:
https://www.youtube.com/watch?v=DPwoFnQnBPk (https://www.youtube.com/watch?v=DPwoFnQnBPk)
Company URL:
http://magswitch.com.au/ (http://magswitch.com.au/)
An obvious question (at least to me) is, how much force does it require to turn the knob from 'on' to 'off'? I would assume it exceeds the force of the magnets in the 'on' state, when combined with losses used to produce useful output energy e.g. a generator, i.e. it might not be viable as a magnet motor...
However...thinking about how one might use this to produce rotation..you could try using them as stators and the rotor 'heads' would be metal blocks.
Quote from: NTesla on May 05, 2015, 05:05:50 PM
An obvious question (at least to me) is, how much force does it require to turn the knob from 'on' to 'off'? I would assume it exceeds the force of the magnets in the 'on' state, when combined with losses used to produce useful output energy e.g. a generator, i.e. it won't be viable as a magnet motor...
@NTesla,
That's a pretty big assumption on your part Bub! He'd need a hydraulic jack to pry that magnet off without the switch.
Quote from: synchro1 on May 05, 2015, 05:14:59 PM
@NTesla,
That's a pretty big assumption on your part Bub! He'd need a hydraulic jack to pry that magnet off without the switch.
To pry them apart without the outer rings for sure...looking at it further given the size of the knobs (i.e. they are not strong levers) means that the force required is probably quite small! So my assumption may indeed be incorrect. How much force is required is the question...
I have some diametrically magnetized magnets I could try this out with. I don't have access to a lathe to machine the outer rings however perhaps thin sheet steel wrapped around (like transformer laminates) might do the trick - plus you can build up each layer until you reach the desired effect.
Here is a demo video of one of the companies products:
https://www.youtube.com/watch?v=N13HkxyRsZc (https://www.youtube.com/watch?v=N13HkxyRsZc)
...And a review video demonstrating turning of the knobs...
https://www.youtube.com/watch?v=3VLRlKr3G1U (https://www.youtube.com/watch?v=3VLRlKr3G1U)
@NTesla,
The guy looks like he's applying around five pounds of force to levering the switch in that video. That would accelerate an iron rotor with four hundred pounds of force if switched off at TDC. That's an eighty to one gain! I would just buy one of those switches for the hundred bucks from K&J Magnetics to experiment with.
Quote from: synchro1 on May 05, 2015, 06:01:39 PM
@NTesla,
The guy looks like he's applying around five pounds of force to levering the switch in that video. That would accelerate an iron rotor with four hundred pounds of force if switched off at TDC. That's an eighty to one gain! I would just buy one of those switches for the hundred bucks from K&J Magnetics to experiment with.
Hundred bucks!? The link to the manufacturer has just the MagSwitch (60lbs of force) for $17.75US here
https://mag-tools.com/magswitch-magjig-60.html (https://mag-tools.com/magswitch-magjig-60.html)
I think I might buy a couple and do a proof-of-concept design...see if I can get a rotor to rotate using the Mag-switches with either a iron rotor block or perhaps a magnet. Even with the losses from the metallic ring around the switch it may still work...
Quote from: synchro1 on May 05, 2015, 06:01:39 PM
@NTesla,
The guy looks like he's applying around five pounds of force to levering the switch in that video. That would accelerate an iron rotor with four hundred pounds of force if switched off at TDC. That's an eighty to one gain! I would just buy one of those switches for the hundred bucks from K&J Magnetics to experiment with.
This is one of their cheaper items
Magswitch Mag-Utility Hook 25 8100012
$33.60 at CyberWeld
http://store.cyberweld.com/mamahaho30.html (http://store.cyberweld.com/mamahaho30.html)
These are also very goo (and strong)
http://store.cyberweld.com/stwemaadohed.html (http://store.cyberweld.com/stwemaadohed.html)
I use MagSwitches often.
They have been around a long time in one guise or another.
They are used very often in welding.
They are a very common earth clamp nowadays.
Also many other magnetic welding holddowns.
I can't see any FE benefit from these, but they might be fun to play / experiment around with.
It takes a few pounds of force over a half turn to go from on - off and vice-versa.
But the switch does replenish energy in the system.
I am sure I can cause a few thousand pound boulder to roll down a mountainside with a simple lever.
As long as I am not the one putting it there in the first place, and getting it back to the top is the trick.
So definitely not an 80 to 1 gain.
I will get a spring balance from a friend and do a test for you.
I have a Magswitch 300 amp Welding Ground Clamp - (8100315)
You will want to know the pulling force and the radius of the knob correct ?
BTW, the force required to "throw the switch" is not linear.
It goes from very weak at the beginning, increasing to a few pounds near the end of the half turn.
The diameter of the knob is 1.625 inches.
Just a thought :
The linear motion of the other type of clamp
http://store.cyberweld.com/stwemaadohed.html (http://store.cyberweld.com/stwemaadohed.html)
might be easier to incorporate into a test setup as opposed to the rotary motion of a magswitch.
Quote from: PIH123 on May 05, 2015, 07:03:15 PM
I will get a spring balance from a friend and do a test for you.
I have a Magswitch 300 amp Welding Ground Clamp - (8100315)
You will want to know the pulling force and the radius of the knob correct ?
BTW, the force required to "throw the switch" is not linear.
It goes from very weak at the beginning, increasing to a few pounds near the end of the half turn.
The diameter of the knob is 1.625 inches.
Just a thought :
The linear motion of the other type of clamp
http://store.cyberweld.com/stwemaadohed.html (http://store.cyberweld.com/stwemaadohed.html)
might be easier to incorporate into a test setup as opposed to the rotary motion of a magswitch.
@PIH123,
"Strong Hand® MSA46-HD Adjust O Heavy Duty On/Off Welding Magnet
"has patented ON/OFF switch", making positioning easier and safer".
I've played with this model at "Harbor Freight". The switch force is small. The problem is that the one switch operates the two faces.
Here's their Dual Switch model:
Adjust-O™ 90° Dual Switch Magnet Squares
Angle magnet squares with the convenience of On/Off switches.
For professional jobs that demand strong hold down forces. Hold flat and round metal work pieces.
•Two On/Off switches for independent operation.
•Turn the magnets Off when setting up, turn On when you're ready to work. Easy and safe set-up!
•Precision machined flat and V-surfaces are ideal for round and square tubing, angle, and flat stock.
•Choose from 120 - 265 LBS (55 - 120 kg) pull force.
A small servo and trigger switch would deliver 265 pounds of pull force at TDC to the ferrite rotor from one face! This model would spin a very large and heavy iron rotor. Saturation's our enemy, so slow and heavy is best. This model could probably power a large 360º pendulum. Naturally, "High Permeability" rotor material would allow for higher R.P.M. It might be possible to use both 90º magnet switch faces with an "L" shaped rotor.
Think about it; There has to be enough force from hundreds of pounds of pendulum propulsion to trip that tiny switch back and forth. Archimedes!