You can find a nice picture of the components for an electric motor in this photo below. If you want to learn more about brushless motors, you can checkout this informative page here on brushless motors.
The C Clip / Cir-Clip
The C Clip is an important part because it keeps the rotor and stator together as one piece. If the C clip breaks and/or isn't there. The rotor and stator can come apart. The C Clip holds everything together. You do not want to damage the C Clip and/or have it running into your electric longboard motor mount as it can damage and/or break your C clip when rotating.
Make sure that the Cir-Clip is able to spin freely without hitting into anything when your motors are spinning. If you need to space it away. You can use M4 washers between the M4 mounting bolts and the motor to add a gap for the c clip to spin freely.
I broke a C Clip! What do I do?
If you ever do break the C clips. You can purchase a C clip with the diameter of your motor and also purchase the c clip pliers.
The Motor Housing usually will have two set screws which hold the motor shaft in place. I prefer to make sure that these bolts are tight as they can cause shifting with the motor mount and housing. Set screws also tend to strip when you put force or torque on it. For this reason, I usually always swap my bolts to cap head versions as they are less likely to strip the head when using force.
I would also suggest getting Blue Medium Thread Lock to help it stay in place. Usually the bolts are either M3 or M4 depending on the size of the motor. This 50mm in the photo was an M3 bolt.
The motor wires are very critical as well and should not be stressed or near the motor as it can grab onto the motor wires and damage the wires.
I do like to heatshrink wrap on top of each motor wire to add a second layer of protection that way the wires don't get cut or snagged when the motors are spinning underneath your electric skateboard.
I then heatshrink all three wires together as one but only half the distance which will also make it much stronger.
The motor pulley is also another very important part and should be done properly the first time around.
This motor pulley is based on the parts we sell here at DIYElectricSkateboard.com. We include a keyway slot which allows more torque to pass through versus using set screws on the hub pulley solely.
They keyway may need to be sanded down to fit properly and/or make clearance. You can also use a dremmel and/or sandpaper to accomplish this task.
The best way to create the flat spots would be the following steps below:
1. Sand the Keyway to Size
Make the keyway fit into the keyway slot by using a dremmel, sanding the keyway down from the sides. The easiest way is using a dremmel.
2. Fit the Keyway into the Motor Shaft Keyway Slot
3. Attach the Motor Pulley
Create a mark with a permanent marker where the set screw will be placed. The flat surface allows the bolt to be stagnate and not move around and/or slide out through vibrations.
4. Change the M3 Set Screws to M3 Cap Head Bolts
There are many benefits to switching over from a M3 set screw to an M3 Cap head bolt. First off the torque power for a Cap head is much higher than a smaller size hex screwdriver.
Don't forget to add threadlocker to your bolts to prevent slip out.
There you have it!
Finalize your motor pulley on your motor shaft by bolting it on. Then go ahead and enjoy!