Authored by Stuart Skjerven:
Matched motor mags have been checked for relative strength. A motor will run much more smooth if the north and south mags have the same strength. If one is alot stronger than the other then the motor will lope as the arm spins faster towards the strong mag and slower towards the weak one. There are many different ways to check a magnet's strength. You can buy an expensive Gaussmeter ($400 and up), you can buy a Trixtraxs Mag Matcher ($170), or you can just use a stack of washers and see how many washers each mag will lift. Before I bought the Mag Matcher, my favorite way to match mags was to fill a film canister with beebees and glue a washer on the lid so the mag had something to grab. The most important part of this process was determining what a clean lift was and of coarse keeping track of how many beebees you have in the canister. Getting the mags matched to within a beebee or two is a pretty good match.
I am still learning when it comes to mags as there are several other things to look for in how the magnet field is distributed on the inside face of the mag and then how you position them up or down in the bulkheads to get the best rpm from your arm. Matching mags, a well balanced arm, a true com, and spacing the arm properly in the magnetic field are key to a smooth fast Tyco.
Paul Roman:
It is a little tricky, but you can get them close with a sheet of paper and a compass. Put the compass in the middle of the paper, and draw some concentric circles around it to measure the distance from the center of the paper. Then take your magnets one at a time and begin at the edge of the paper and slowly move them closer to the compass. When the compass moves mark the paper, and the magnet with a number based on the distance away from the center of the paper. Then just pair the magnets with the closest numbers. Presto, matched magnets.
For optimizing an armatures performance the pole should be as straight as possible, the commutator should be true, and the motor magnets should be matched. A gauss meter may be used to match magnets, although this is about $400. Tjet magnets range from 200 - 1000 gauss, magnet cars run between 1100 and 3000 gauss.
BRP Magnet Matcher
Trik Trax Magnet Matcher
Building your own Gauss meter instructions!
Yokomo RC gauss meter
|
