hankster
02-01-2005, 12:24 AM
You've followed the directions for aligning your brush hoods exactly like it says in the Black Book of Motors. And the commutator is still wearing the brushes on one side. How come?"
Here are a few advanced tips and how you can be fooled when aligning your brush hoods.
1. You must use the same size "test" brush as the ones you are going to finally put in the motor. This is a common mistake. If your test brush is bigger than your race brush, it won't shift as much in the hoods. This will cause the comm to wear on the leading side of your race brush. If the test brush is smaller than your race brush, it will shift too much and the comm will wear on the trailing side of your race brush.
2. Don't just spin the armature by hand to check the wear mark. You have to make the wear mark on the brush by running the motor under power. Otherwise, it may not shift the same way and throw your alignment off.
3. You can use the same pair of test brushes many times. Look up a welding supply place in the phone book. Go there and get a BRASS bristle brush called a "toothbrush" because it's a small wire brush similar in shape. It's less than $3 and is soft enough to "wipe out" the wear mark on your test brush without distorting it. This way, you can use the same pair over again. Eventually, all the different wear patterns from all the comms will change the curvature of the brush and make it shift differently in the hoods so replace them once-in-awhile.
4. Visualize how the brush is shifting in the hoods. If you do this, you can determine what needs to be done to the brush hood to counter-correct the shifting. Don't just move the brush hood up or down while still being pushed against the endbell (or heatsink). You'll change the timing. Usually, the leading side of the brush hood has to be kicked out or away from the bushing tower while the trailing side stays tight against the bushing tower.
5.Use the alignment tool! Don't use your fingers or pliers. Get the tool. Racer's Edge sells one and so does Niftech (the Niftech one is lots more expensive and does the same thing). Only with the tool can you keep enough "pulling down" pressure on the hood to tighten the screws and keep it there. The tool also keeps the hood sized properly (not too small anyway) as you pull and push to align.
6.Enlarge only the spring post hole. Most motors don't need the endbell mounting holes enlarged to properly align the brush hoods. There's enough play in the holes to twist the hood/heatsink assembly with the tool to correct the misalignment. The Yokomo MVP is an exception. Just elongate (make the hole oval shaped) toward the endbell slightly. Don't do anything to the Phillips screw hole. It's large enough already. If you enlarge both screw and spring post holes, you won't have a reference point when you put the endbell back together and you probably will never get them aligned right.
7. Move the brush hoods and heatsink as one assembly. Don't try to move just the hood on top of the heatsink to align. On Epic motors, the "dimples" will prevent that anyway. Move everything together.
Here are a few advanced tips and how you can be fooled when aligning your brush hoods.
1. You must use the same size "test" brush as the ones you are going to finally put in the motor. This is a common mistake. If your test brush is bigger than your race brush, it won't shift as much in the hoods. This will cause the comm to wear on the leading side of your race brush. If the test brush is smaller than your race brush, it will shift too much and the comm will wear on the trailing side of your race brush.
2. Don't just spin the armature by hand to check the wear mark. You have to make the wear mark on the brush by running the motor under power. Otherwise, it may not shift the same way and throw your alignment off.
3. You can use the same pair of test brushes many times. Look up a welding supply place in the phone book. Go there and get a BRASS bristle brush called a "toothbrush" because it's a small wire brush similar in shape. It's less than $3 and is soft enough to "wipe out" the wear mark on your test brush without distorting it. This way, you can use the same pair over again. Eventually, all the different wear patterns from all the comms will change the curvature of the brush and make it shift differently in the hoods so replace them once-in-awhile.
4. Visualize how the brush is shifting in the hoods. If you do this, you can determine what needs to be done to the brush hood to counter-correct the shifting. Don't just move the brush hood up or down while still being pushed against the endbell (or heatsink). You'll change the timing. Usually, the leading side of the brush hood has to be kicked out or away from the bushing tower while the trailing side stays tight against the bushing tower.
5.Use the alignment tool! Don't use your fingers or pliers. Get the tool. Racer's Edge sells one and so does Niftech (the Niftech one is lots more expensive and does the same thing). Only with the tool can you keep enough "pulling down" pressure on the hood to tighten the screws and keep it there. The tool also keeps the hood sized properly (not too small anyway) as you pull and push to align.
6.Enlarge only the spring post hole. Most motors don't need the endbell mounting holes enlarged to properly align the brush hoods. There's enough play in the holes to twist the hood/heatsink assembly with the tool to correct the misalignment. The Yokomo MVP is an exception. Just elongate (make the hole oval shaped) toward the endbell slightly. Don't do anything to the Phillips screw hole. It's large enough already. If you enlarge both screw and spring post holes, you won't have a reference point when you put the endbell back together and you probably will never get them aligned right.
7. Move the brush hoods and heatsink as one assembly. Don't try to move just the hood on top of the heatsink to align. On Epic motors, the "dimples" will prevent that anyway. Move everything together.