Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: First post here and my first doubt (safety concern)  (Read 5591 times)

energy-librarian

  • Newbie
  • *
  • Posts: 3
First post here and my first doubt (safety concern)
« on: October 26, 2010, 10:48:23 PM »
Hi, I am Alejandro, 43 years, from Uruguay, South America. ;)
My question is: are permanent magnet motors out of control devices? I mean, how is the start/stop procedure?  ???
Of course I am not referring to motors that use electromagnetic shielding.

gyulasun

  • Hero Member
  • *****
  • Posts: 4117
Re: First post here and my first doubt (safety concern)
« Reply #1 on: October 26, 2010, 11:58:50 PM »
Hi Alejandro,

If I could design such permanent magnet motor, then I would build some of the magnets to be detachable on the stator parts or maybe would use iron plates of suitable sizes to insert into the possible air gap between rotor stator to block the interacting flux.

rgds,  Gyula

spinn_MP

  • Full Member
  • ***
  • Posts: 224
Re: First post here and my first doubt (safety concern)
« Reply #2 on: October 27, 2010, 12:07:38 AM »
Hi, I am Alejandro, 43 years, from Uruguay, South America. ;)
My question is: are permanent magnet motors out of control devices? I mean, how is the start/stop procedure?  ???
Of course I am not referring to motors that use electromagnetic shielding.
Good point, safety comes first!

Yep, it seems that PMM's are quite dangerous devices - starting is not a problem, but stopping...?
Believe me, you wouldn't want to try to stop one of those beasts, after the start up....

It seems that almost all the successful inventors from the past vanished (have been vaporised?) while trying to stop their "permanent magnet motors"....
 ;D



Just kidding, don't worry.. You'll be safe.

Maybe... But watch out the MiB's....


(Kidding again, of course...)

Welcome!

TinselKoala

  • Hero Member
  • *****
  • Posts: 13958
Re: First post here and my first doubt (safety concern)
« Reply #3 on: October 27, 2010, 01:26:37 AM »
There actually are some real safety concerns.

First, the material that NdBFe magnets are made from, is FLAMMABLE and TOXIC. If you try to grind or cut this material you are risking a FIRE that will emit very TOXIC fumes.

Second, the magnets themselves are a PINCH HAZARD. You can be severely injured if you let your fingers or other flesh come between two NdBFe magnets that are loose and flying around.

Third, rapidly rotating assemblies that contain NdBFe magnets should rely on MECHANICAL RESTRAINTS and MOUNTS for the magnets, NOT GLUE. Any adhesive can fail, and will usually do so at the worst possible time: when the device is spinning fast.

Fourth, NdBFe magnets are BRITTLE and will break or SPALL OFF tiny bits if they are allowed to snap together uncontrolled. These little bits will be RED-HOT, flying FAST, and can do serious damage. WEAR EYE PROTECTION.

Fifth, if you have small children or animals, BE SURE that they CANNOT SWALLOW any of your magnets. It can kill them, by causing intestinal adhesions or blockages.



One thing you will NOT have to worry about is "how to stop a runaway magnet motor".

Jehoiakim

  • Newbie
  • *
  • Posts: 1
Re: First post here and my first doubt (safety concern)
« Reply #4 on: October 27, 2010, 08:55:46 PM »
If you wanted to "cap" the speed of rotation, you may want to investigate the the theory of operation of centrifugal governors - as the rotational speed increases, you could have the centrifugal force of the spinning governor increase friction on either the drive shaft or a flywheel (if so equipped) shaft to keep RPMs at a reasonable speed.

As for stopping it, perhaps a friction brake on the drive shaft or the flywheel shaft.

Or, dunk the entire PMM into water - I'm sure the 1500% increase in the operating environment's viscosity will have the desired effect.  :P   

Low-Q

  • Hero Member
  • *****
  • Posts: 2847
Re: First post here and my first doubt (safety concern)
« Reply #5 on: October 28, 2010, 10:51:32 PM »
Hi, I am Alejandro, 43 years, from Uruguay, South America. ;)
My question is: are permanent magnet motors out of control devices? I mean, how is the start/stop procedure?  ???
Of course I am not referring to motors that use electromagnetic shielding.
Yes they are out of control motors - no one has ever got one working. No control, no clue.
Unfortunatly true in most cases. All "working" magnet motors this far has been frauds. I look very much forward to the day we finally know how to do it right.
Many theoretical motors that "works", but they always works differently in practice...

Generally speaking: A magnet motor will account for all forces and counterforces for each revolution of the rotor. Basically this means the rotor find its very same potential for each time the rotor passes tits initial base. So therefor, and for that simple explanation, a magnet motor will not work - unless some genious find a way to make magnetism extracting energy from somewhere else. But then that "somewhere else" will loose its potential energy level as we use it...

Kinetic energy is all about balancing two different potential levels. In the period this balancing are finding place, it can do work. Ofcourse, MAKING this inbalance in the first place, will also require energy input by balancing energy levels from somewhere else. So a magnet motor will work as long someones hand are forcing the rotor to turn around - as seen thousands of times on youtube...

IF a magnet motor worked, it will probably NOT go out of control. The torque are limited to the force provided by the magnets, and the maximum energy output of such a device relies on these forces per meter, times revolutions per second - or something.
Vidar