Latest Permanent Magnet Motors Auctions

Hey, check out these auctions:

Gettys Permanent Magnet Field Servo-Motor

US $475.00 End Date: Saturday Sep-04-2010 12:41:56 PDT Buy It Now for only: US $475.00 Buy it now | Add to watch list

Pittman 23186 Permanent Magnet DC Motor with encoder

US $44.10 End Date: Saturday Sep-04-2010 17:09:51 PDT Buy It Now for only: US $44.10 Buy it now | Add to watch list

Technorati Tags: Auctions, latest, Magnet, Motors, Permanent

PHYSICISTS! I Can you make a motor using permanent magnets? Doesn’t it break the law of conservation energy?

I saw this on you tube. Where is the energy coming from??????? And if this is real why can’t we use this for cars???? I think that they have some guy with an electric motor hooked up to it.. http://www.youtube.com/watch?v=YvHb41KP7To

I watched all the videos.

In the first video, the demonstrator spins the device and claims that it will spin forever. It’s not very credible.

In the second video, you can’t see entire machine, but in a different video with the same machine, the demonstrator spins the device and it goes for a while and then he spins it some more to keep it going. No energy being generated there.

In the final two videos, the demonstrator gets the wheel to spin by pushing and pulling a magnet near the wheel. When he stops moving the magnet, the wheel slows down and eventually stops. Sorry, no motor here either.

The moral of the story is this: you can’t make a motor out of permanent magnets.

Can I run a 12V DC motor on 24V?

I have a 12V DC motor (permanent magnet) that has a current draw of 60 amps. Can I run it safely on 24V or will I fry it?

You can run it safely for a couple of minutes. Then it will be fried.

Seriously… you will need a switching down converter to run that motor. A 60-100A PWM controller will probably do. Just make sure that it never goes above 50% duty cycle.

what type of magnets are used in ……..permanent or temporary?

we use permanent magnets in d.c. motors,but what kind of magnets do we use in eye treatment,electric bell and relays.permanent or temporary?

In big electric DC motors, "temporary" magnets are used, only in small ones are permanent magnets used.

Electric bells and relays use different forms of electromagnets (temporary).

I’ve never heard of any magnet used in eye treatment.

Does the magnet affect the power of a motor?

In any electric motor that uses permanent magnet poles, does the strength of the magnets affect the power output of the motor?

Let say I have two different motors that are almost exactly the same, but one uses more powerful pole magnets, if I pass the same current through each one, which one will run faster?

Yes, maybe not faster, but more torque.

how many blades are best for a wind turbine?

how many blades does a wind turbine need? some have three others have four. What is best? Mine has four and is 3ft and homemade it runs from a permanent magnet dc motor is it best to have three blades or four for best output?

My husband works on the commercial wind turbines. THE most efficient wind turbine ever developed has only ONE blade!!

Generally speaking, three blades are best, or any ODD number. It is easiest to balance anything with blades, when they have an odd number of blades.

This goes for ceiling fans, wind turbines, prop airplanes, ect. It’s much, much easier to keep everything nicely in balance, and not wear bearings out, with an odd number of blades.

~Garnet
Permaculture homesteading/farming over 20 years

what is the function of the permanent magnet in an electric motor?

It provides the magnetic field which (in combination with rotation) is the basis for generating voltage in the motor. By the way motors do not have to have permanent magnets, indeed most and especially larger ones, use electromagnets to generate the field.

EDIT: to gintable: No Bramble did not speak just about a generator. In fact he didn’t speak at all and what he wrote was about motors! Generators and motors in their various types are not at all opposite but rather extraordinarly similar. A motor generates an emf exactly as a generator does. The salient difference between the two is purely mechanical – the motor drives; the generator is driven. You’ve maybe had too much gin on the table!

Will running a homemade wind turbine without a load hurt it?

I’m in the process of building my first wind turbine and was curious if running it without a load (ie. battery bank) would be harmful to the generators? I’m using a 260VDC 5A permanent magnet treadmill motor as the generator. I’m about ready to put up my tower and wasn’t sure if I can go ahead and get it all assembled and put up and then add the battery bank as soon as I can get the batteries. This way I could also see how well it’s going to perform on the tower. It’s a 60′ lattice tower and will be hinged at the bottom but still will be a bit of a pain to lower and raise a lot. I’m really excited about getting this up and running but don’t want to damage anything before I even get started.

Also I’ve heard of people using old electric baseboard heaters as a load dump when the bank gets fully charged. I’m having some trouble locating any of these around here and was wondering if anyone would have any other suggestions on something I could use as a dump? Thanks for all your time.

You will wear the bearings a bit, but there
will be no damage to the generator from
turning without load.

How do you intend to prevent overspeed in
a high wind though?

As to the load bank, if its only 5A., the nichrome
wire units from an old toaster or two would do it.
(Leave em on the mica in free air.)

Will this set up with permanent magnets create heat through induction?

Suppose I have two permanent magnets at opposite sides of an imaginary circle, and in the middle of the circle, between the magnets, is a piece of iron attached to a stick attached to a motor. When the motor starts spinning the iron, will it heat up at all like in a typical induction heater with alternating current? Will I get any heat at all? Would it be more likely to work with 4 magnets around the perimeter instead of 2?

Yes it will heat up because of hysteresis losses. Actually steel will heat up a lot more than pure iron, because it has a wider B-H curve i.e. more hysteresis loss. More magnets around the perimeter will increase the effect, but it is ultimately limited by power from the motor.

What would a motor made with only permanent magnets be potentially worth?

A motor made only with permanent magnets only would lead to a re-write of the laws of thermodynamics, as it would be a perpetual motion machine. It would solve all the world’s energy problems, and the person who invented it would become the richest and most famous inventor ever.
Many have tried to create such a motor, some have claimed to succeed, but as far as I am aware none have withstood scrutiny without being exposed as frauds.