30 replies to this topic

[robbovius]

Edited by Robb:  One South pole will be the concave face ( with the convex face "north" ), the other will be (south) convex face, (concave face north).  With the motor can in an anglewinder/sidewinder position (LH side gear), place the South convex (North concave, the "North" magnet) face magnet in the rear of the can, the other (South concave/North convex, the "South" magnet ) magnet in the front.  Positive brush will be in the front of the motor. 

 

okay, so if we identify each magnet by the polarity of its concave face, in your example, the "north" magnet is to the rear of the can, and the "south" magnet is towards the front, armature rotation is CCW (viewed from the endbell, motor is assumed to be can-drive), and the positive lead is on the fwd "south" magnet side.  for a can drive motor, facing the endbell, the "north" magnet is to the left, and the "south is to the right, + terminal is on the right.

 

thus, the positive terminal is oriented to the "south" side of the motor, correct?

 

Paul I'm a repeat customer of PCH ;-)  I checked their site, but wound up getting some  shim stock from Grainger (customer of theirs too, for both work and automotive projects) in .004, ,005 and .007 thicknesses

[havlicek]

 

 

Oh I almost forgot...how do you identify the + and - leads when you're reassembling a motor?

 

Easy.  Hook up the motor to a power supply (low voltage), when you hook up the motor, whichever way has the motor turning in the right direction is the way you mark the polarity

 

-john

[Pablo]

The "right" direction being the direction it spins faster, as opposed to the direction it needs to go in a car.  Easy to detect by ear when there is any appreciable amount of timing. With neutral timing it will spin equally well in either direction.

 

I have a different way of explaining magnets that may or may not be easier for you to digest. Although it is functionally no different than what Hermit and H posted.

Cheater Wells taught me a magnet is "branded" by it's concave surface. In other words, with the motor installed in a left (port) side can drive anglewinder or sidewinder, hold the compass to the rear of the motor - if the needle indicates north, the rear magnet is a "South Magnet". Because convex and concave sides of the same magnet are always opposed. So that rear magnet's concave face is south. The only time this magnet placement matters is when you want your lead wires to connect to the same terminals after a motor job. 2 examples, 1) a wing racer who is continually removing and refurbing motors doesn't want to have to guess which wires go where in the heat of the battle. If he or she makes the forwardmost terminal always the positive, so it's always standardized, it's important to get the mags the same way every time. 2) a vintage inline car that has wires routed a certain way needs to use the same terminals on same wires after a rebuild. Although it is easy to switch the wires on an inline.

 

Bottom line is, the arm needs to spin in the direction the comm tabs are advanced. This drives every other factor.

 

Again, I don't think I said anything different than anybody else here.

 

A trivia question for you, if a ship is on course 000 degrees magnetic, and comes left to new magnetic course 263, how many degrees does the compass needle move ?

[Don Weaver]

97?

[Outlander]

0 Degrees

[Pablo]

Bingo, Bob

 

Sorry Don, I tricked you. The compass needle always points to magnetic north. The ship moved 97 degrees

I'll go back to my La Cucaracha cave now