Magnet Tipping

[Rush]

Hi Monty,

Can you help me out on the location of the magnet tips? You had covered this in previous old thread but I'm a little confused with tip placement after thinking about it.

I did place them at the 2 o'clock (positive) position and and 7 o'clock (negative) position and man what a difference. My Son and I had the 2nd and 3rd fastest cars for qualifying times!! I had placed the strong side of the tips to the end-bell side when possible. Some motors I had to place the magnet tips (same position 2 & 7) but opposite of each other. One on the end-bell side and the other on the drive side. I did not take note as to which motor had the tips in there respective position because at the time I thought it didn't matter :confused: Does this matter?

Also which is the preferred way to zap magnets? I read that magnets can be zapped while in the can. Should I remove the armature before doing this?

As always thank you for sharing your knowledge young masterful one. :D

Rush

[[email protected].]

Rush,

People call me many things... young ain't one of them:p

I presume you're talking about where to place the STRONGER of the two tips on a magnet. We talk about the trailing edge or leading edge, defined as the last or first edge a pole encounters in its normal rotation. I beleive in placing the strong tip at the trailing position: this is indeed 2 and 7 on the clock IF YOU ARE LOOKING INTO the open end of the can, i.e., from the endbell end.

I am confused by your reference to endbell and drive end not as a point of view, but as a location. The tip is taken as a whole, I have no methadology to spot hot spots along its length. How are you doing that?

If you zap magnets in the can, its best to remove the armature but leave a plain round slug in its place (steel, of course). Otherwise, as in a sealed motor, zap it twice but advance the arm one cog notch in between hits. Do not zap magnets without anything in the hole, as it can change the shape of the field enough to hurt performance.

[Rush]

I am confused by your reference to end bell and drive end not as a point of view, but as a location. The tip is taken as a whole, I have no methadology to spot hot spots along its length. How are you doing that?

Sorry for the confusion Monty. For me it's hard to describe something in a email when especially I don't have the correct terminology. This occurs because I didn't fully understand what I had read.

I thought about your question all night and it finally sunk in. I think. :confused: I'll try to explain what I did.

I used a Gauss meter (wand) and checked the field strength on the four corners of the magnets edges and not the entire length of the edge. The four corners of the magnets edges (tips) I call them, did give me different strength readings. To achieve a consistent comparable I drew a black line on the wand and place it the same way on all corners (tips) to get a consistent reading by doing it the same all the time. This is the only way I can do it at this time using a wand. I know you don't like using a wand but this is all I have at the present time.

I try to place the wand in the same position of the magnets center to get inside field strength reading and for matching.

So leading and trailing edge of a magnet you are referring to the entire length of the magnets edge and not just the corners of the edge?

For some reason what I did worked...LOL Now I know why it works I think. :(


The end bell side is just that. It contains the brushes ect. The drive side I refer to is the opposite end that holds the pinion that drives the gear.

Peoples terminology is confusing at times when explained in writing. I should of paid more attention in school so I could write better. :D

I hope I'm more clearer on my explanation and my understanding on this subject. :)

Thanks Monty for your help.

Rush

[[email protected].]

Rush,

Yes, I apparently understood exactly what you meant, and you understood me.

My bias against the wand type probes has little to do with accuracy or ease of use, but rather in the difficulty in deriving truly meaningful results. Yes, you can find hot spots all over a magnet, including along the length of the tips. My arguement is that the hot spots don't mean much: stuff happens in your motor at extreme speeds. They rotate at 100k rpm and more... an armature pole reacts, at best, to an average of the field its operating in. It also creates a counter field which is best viewed as an average. Sure, the centerline of each pole is the strongest point magnetically, but this field is reversed twice per rotation. The field at the arm pole tips has to be quite small, since they come down to a virtual knife edge with little mass, yet wider pole faces do make more power. The RJR narrow pole arms of a few years back were all RPM. Power is a product of RPM AND torque. When I made my big blank with wider crowns, it wasn't hard to beat the narrow crown arms of the same diameter on most tracks and power supplies. Is the difference huge? No, but any decent racer can make 1 % stand up to competition.

In my opinion, average models of the goings on in our motors are the only theories that make sense. Its sort of like the models of atomic structure. Atoms are mostly empty space, but the extreme speeds of electrons in their orbital paths make atoms behave like little solids.

Bottom line: consider the strength of the tip, not any spot along the tip. Marking off a length of your probe equal to the magnet length should allow repeatability of the readings.

[Rush]

Sweet!! I feel better known we are thinking and saying the same thing.

I'm crazy over this stuff and I want to learn everything possible in building these little power plants.

Knowledge is power. Thank you so much for sharing your knowledge. Some people don't share there knowledge and to you Sir I commend you for doing so.

Teach me more!!! :D

Rush