Advancing timing on XMods motors
 

Since people have been asking about it, here it is: All you are doing is twisting the commutator relative to the rest of the armature. When you advance the timing on the motor, you gain top speed (in the forward direction, while losing speed in the reverse direction), at the expense of a little bit of torque. There are limits to how much advance you can get away with before the motor starts running poorly. Stick with what I show in the pictures and you will find the gains to be worthwhile without being too risky.

The first two pictures show the armature with neutral timing. Note how the commutator contact is centered in the gap between the poles of the armature.

http://users.adelphia.net/~neurokine...ral_timing.jpg
http://users.adelphia.net/~neurokine...al_timing2.jpg

The next two show the timing advanced. I try to twist the commutator so that the contact is even with the edge of the pole.

http://users.adelphia.net/~neurokine...g_advanced.jpg
http://users.adelphia.net/~neurokine..._advanced2.jpg

To (gently) twist the commutator, I just grasp it in my fingers, while holding the pinion gear in my other hand. It is possible (and advisable) to do the timing adjustment without removing the armature from the can, as pinion removal tends to force the brass spacer at the front of the armature into the armature windings, causing excessive longitudinal play within the motor. Note that there are small nubs on the end of the commutator that hold it in a neutral position. When you twist the commutator, these nubs will break, allowing it to move. Once you have it where youwant it, you could use a drop of CA glue or the like to hold it in place (towards the windings), though I don't bother, since the rotational force of the motor is primarily on the armature poles, and the commutator is just along for the ride.

Last thing to note is that you create a bit of slack in the windings by doing this, so I tend to try to pull them tight at the contacts, as shown in the bottom picture.

everytime i open and close a motor, it doesnt work anymore, i cant get the brushes set in properly, do u have any tips???

When you remove the endball, leave the caps soldered to the can, and remove the endbell separate from the brushes. After removing the endbell, just gently pivot the brush assembly out of the way. Try not to let the brushes get bent at all. When rotating them back into place, you will need to spread them gently, so that they clear the spacer washers at the bottom of the commutator. Once the brushes are in place, then put the endbell back on. If you do this properly, everything will work when you get it back together.

neurokinetik thanks for the pictures. I was trying to advance the timing with the brushes but caused to many problems.

Which motor were you installing the SpinBrush magnets into. Stock, Stage 1, or the Stage 2 motors?

I've tried them in just about everything, actually. The only thing they didn't work well in is my custom 25 turn motor.

I really like them in the stage 2 drag motor with the timing advance.
With that setup, I dragged against a pretty much identically modded Supra with a stock stage 2 drag, and walked him pretty bad from the start and kept right on pulling until the end...

What do you think the max timing is? I only ask b/c I assume the picture you posted is a fairly conservative setup. Thanks


sherif

btw, HUGE thanks for posting this info up!

According to what I've read, 20-25° is the most advance you would normally want. Too much advance causes overheating due to very high current draw. Putting my protractor on the screen shows that I am getting 15-18° of advance by twisting the commutator. Unfortunately, it is a bit more difficult to do it this way with as much precision as the 540 motors give with their adjustable endbells.

is there anyway to retard the timing?

Yeah, turn the commutator the other direction. (Clockwise)

how are you pulling the tabs that hold the wires in, back?


sherif

do you mind putting up a couple pics showing how to properly take off the endbell? that woudl be really helpful

Great info. Thanks for posting. I just did it on a spare stage 1. I am anxious to see the results. Thanks again.

Not sure what you are asking here... are you talking about the tabs on the commutator that clamp the armature wires down?

thats exactly what I'm asking :D

sherif

Well, I haven't succesfully been able to pry them up, so I don't have the answer... :p I just solder the wire to the top of them instead.