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So, I got around to checking on the brushes on my BD36. If you've been following my build thread, you know that I've been running it at 72V, which is a 100% overvolt. Here's how I went about it:
First, take out the screws. If you look really close, you can see that I've cut slots into the heads of several of the screws. They are made of some weird size, and are prone to getting stripped. The slots allow me to use a flathead screwdriver, which is much easier to deal with. ↓
After you take off the screws on both sides, tap the axle on the ground to remove one of the side plates. Note that the side that the wire exits on HAS to come off second. If you try to take it off first, you'll be banging the brush assembly into the commutator plate. ↓
Make sure you take this sleeve off the wires. You might cut into them if you don't remove it and try to take off the other side plate. A little work with a screwdriver will loosen it up, and a little more tapping on the ground should make it come off. ↓
Pic of the rear of the commutator plate. Looks good here. ↓
Pic of the back of the brush assembly. Like new. :wink: ↓
Now, here comes the tricky part: Separating the rotor and stator. This is the safest way I've come up with to do this, and, believe me, you want to be safe when messing with these magnets. They can easily crush your finger. There's probably like 100lbs of force holding this thing together. Stick the axle in a vice (wire side down; as shown) and then push up HARD on the outer housing. Careful to keep your fingers out of harm's way. ↓
Pic of the stator and brushes. One is a little oxidized on one side, otherwise they seem to be holding up well. ↓
The commutator plate, however, isn't looking so hot. There's some fairly bad pitting on the leading edge of a number of contacts, and you see those smooth gouges eminating from the space between the individual contacts? Those aren't supposed to be there. There's also some slot-like HOLES being burned into the side of the plastic. :lol: ↓
Getting the thing back together is pretty much just doing this in reverse. But remember to do this when you put the rotor and the stator back together. Push the brushes into their housings as far as they will go and then use some alligator clips or clothespins or something to clamp down on the wires they attach to on the other side. This will keep them in place when you put the motor back together. If they aren't held there, they could come out of their housings and either not be in place or broken when you try to rejoin the main two pieces of the motor. ↓
Other than the pitted/gouged commutator plate, the motor seems to hold up to 72V well enough if the amperage is held to a reasonable level (I use a 30A controller). I'll keep riding it, in any case. :wink:
First, take out the screws. If you look really close, you can see that I've cut slots into the heads of several of the screws. They are made of some weird size, and are prone to getting stripped. The slots allow me to use a flathead screwdriver, which is much easier to deal with. ↓

After you take off the screws on both sides, tap the axle on the ground to remove one of the side plates. Note that the side that the wire exits on HAS to come off second. If you try to take it off first, you'll be banging the brush assembly into the commutator plate. ↓

Make sure you take this sleeve off the wires. You might cut into them if you don't remove it and try to take off the other side plate. A little work with a screwdriver will loosen it up, and a little more tapping on the ground should make it come off. ↓

Pic of the rear of the commutator plate. Looks good here. ↓

Pic of the back of the brush assembly. Like new. :wink: ↓

Now, here comes the tricky part: Separating the rotor and stator. This is the safest way I've come up with to do this, and, believe me, you want to be safe when messing with these magnets. They can easily crush your finger. There's probably like 100lbs of force holding this thing together. Stick the axle in a vice (wire side down; as shown) and then push up HARD on the outer housing. Careful to keep your fingers out of harm's way. ↓

Pic of the stator and brushes. One is a little oxidized on one side, otherwise they seem to be holding up well. ↓

The commutator plate, however, isn't looking so hot. There's some fairly bad pitting on the leading edge of a number of contacts, and you see those smooth gouges eminating from the space between the individual contacts? Those aren't supposed to be there. There's also some slot-like HOLES being burned into the side of the plastic. :lol: ↓


Getting the thing back together is pretty much just doing this in reverse. But remember to do this when you put the rotor and the stator back together. Push the brushes into their housings as far as they will go and then use some alligator clips or clothespins or something to clamp down on the wires they attach to on the other side. This will keep them in place when you put the motor back together. If they aren't held there, they could come out of their housings and either not be in place or broken when you try to rejoin the main two pieces of the motor. ↓

Other than the pitted/gouged commutator plate, the motor seems to hold up to 72V well enough if the amperage is held to a reasonable level (I use a 30A controller). I'll keep riding it, in any case. :wink: