Motor physics

[5614]

how does this motor work? like what repels what? whats magnetically north/south?

 

motor from the outside:

the round disk rotates

 

remove that metal disk to reveal electronics:

 

close up of that:

the copper are making electromagnets, also notice the permament magnet at the end of each electromagnet, its small but there

 

that metal disk:

picture taken of the bottom side of it that rests on the electronics so is normally not seen... its metalic, notice the magnet running around the outside of it

[The Rebel]

Is this a stepper motor or a power motor. Difficult to tell whats going on in this pics, I think its simply that electromagnets are being energised in succestion, causing the rotating part to constantly align itself, and effecting spin.

[5614]

i have never seen the motor in action but i would expect it to be a power motor.

 

it is from inside a floppy disk drive, or should i say it IS the inside of a floppy disk drive.

 

all the electromagnets are linked together by the same peice of enamel wire (the copper stuff you see which makes the electromag.) so it cannot have seperate electromagnets powered at different times, they are either all on or all off as they are all linked.

 

im sorry about the quality of the pics, it was taken by a £20 (UK) digital camera which is *measuring* 5cm x 3.5cm x 1cm, its not to meant to be for quality!

 

anyone know what is repelling what and causing the rotation of the top disk?

[ed84c]

are you sure there is no capacitors causing a time delay?

[5614]

im guessing you have never studied the inside of a floppy drive, its similar to the motherboard in a computer, you cant tell, besides, look in the 3rd image, there's a white film under it so i cant tell.

 

what i can say is that ALL of the electromagnets are connected by a single piece of enamel wire, and therefore they are all on/off together.

 

i think my prob is how a round magnet could be attracted/repelled, when it is a circle and when all the electromags are on at the same time... i might take it to my physics teacher see what he says.

[ed84c]

aaahh sorry i just thought.

 

Suppose one half of the Magnet (verical) is N and other is S

 

Now Suppose that the electromagnets on one side repel that particular side they are facing, the magnet will spin, providing that force or rotation is enough to prevent the magnet being 'captured' by the force the other side, then the magnet would spin.

 

However if this is the case there must be a mechanism (e.g. electromagnets being shut off before rotation ends) to prevent the magnet from resting (after its rotation) next to the opposite Electromagnet Charge.

 

If you get my meaning

[5614]

well, i assume you were splitting the covering silver circle magnet into North and South, but they prob is that i have this bar magnet which is clearly labelled N and S, you know, those kiddy kits! the magnet shown in the 4th (easy to say which pic than descriptions) attracts N all the way around it and attracts S all the way around it.

 

i think what you were looking for is a commutator, but there's no obvious one and it wouldnt work anyway, there's no obvious N/S for the mag in pic4 (circle one)

 

im totaly confused by it!

[ed84c]

So your saying the middle bit is not a magnet then?

[5614]

im telling ya mate, theres loads of different bits to this motor, say which part of which image so i know what you are talking about!

[ed84c]

sorry, i meant the magnet on the outside. PIC 4

 

You said it was attracted by both north and south, if it was a magnet areas would only be atracted to one.

[5614]

 

the silver in the image is a metalic plate because it feels metal, is attracted to magnets but does not atract other metals.

 

the black bit running around the outside is a magnet because it is attracted to other magnets and also attracts metal.

 

there's a hole in the middle of the silver 'plate' for the spindel of the motor.

 

placing a bar magnet on this side (from camera's view) of the magnet it attract both N and S the whole way around it

[ed84c]

Well although i still find it hard to visualise, an analogy springs to mind that if a compass is placed of a magnet it spins. I suggest they are the same forces in action.

[5614]

well all great inventions are discovered by mistake.... its true!

 

so there i was just playing with a bar magnet and the circle mag pic 4 also posted later in post #11

 

anyway, if you brush it around it attracts to all parts of it, this is what i did.... however if you very lightly, quite slowly brush the north side of the bar magnet around you notice that at 8 points it is repelled.

 

this circular mag (pic 4) which is all one whole magnet has a north-south-north-south field running around it, which is weird as ive never seen one side of one magnet have both a north and a south.

 

then the coils (pic 2 +3) as ive said look like they are connected. but are they? each electromag has a few pieces of enamled wire going in a few out, so i assumed it was incase of failure, but what is they were skipping certain electromags and then wrapping around the next, i mean each goes past, you cant tell if it goes and start coiling or just moves onto the next?

 

im still working on it but those two things should help.

 

previous to those two discoveries i'd asked my physics teacher. he wasnt sure but suggested possibly, although a DC input to device a AC input to motor, a similar effect achieved by a 555 ICC... he also suggested that possibly the magnetic field was induced into the metalic 'shell' in image #4... but that was in a few seconds glance as he had a class and was already 15mins late for them due to others staying behind too!

[5614]

just to end the thread, as you may have guessed from the "1 magnet, 2 poles" thread:

http://www.scienceforums.net/forums/showthread.php?t=8530

the circular magnet featured in picture 4 of the orignal post of this thread is a multipole magnet.

 

what happens is that the electromagnets (picture 2) will turn on in patterns and due to the varying polarities of the permament magnet it will be propelled, i can post a diagram of how later.