Electric Propulsion Systems – De-mystified cont...
A few of the club members that are new to electrics would like to see how to put a system together, in a real installation. This page will walk through a typical electric installation. The components that will be shown are:
Motor (in this case a brushless outrunner)
Electronic Speed Control (ESC)
Battery (Lithium Polymer or LiPo)
Battery Connectors (Deans' Ultra)
Receiver
Left out will be the control servo installation. These are installed the same in an electric installation as a glow/gas installation, if doing a converstion at least. For smaller electrics, there are some differences in the size of the servos and how they are mounted but the basics are the same.
Let's take a look at the system. The motor is a brushless outrunner style. The one being used is not convertible. What does this mean? It means that this one can only be mounted one way. There are motors that can be converted from front mount to what is commonly referred to as an "X" mount. In the "X" mount situation, there is a mount that screws to the motor and what would be considered the output shaft is pointing inward towards the fuselage. An adapter is mounted to the "new" front of the motor for the prop to connect to. These motors offer a little more versatility in mounting to a particular fuselage or wing. This is not necessary however. If you know how you need/want to mount your motor, just make sure it has the appropriate mounting system for your application. The two methods are also called tractor and pusher. The pusher style will use the aft-mounted "X" mounting system. The tractor style is mounted (typically) through the front of the fuselage or to a motor mount with the screws in front of the motor. This seemed backward to me for a very long time. However, most of the wings will use an "X" mount and are mounting facing aft. They are in essence, pushing the plane forward. The tractor style was the original style for motors mounted up front, pulling (like a tractor) the airplane through the air. Simple no? Didn't think so.
The two motors above show the basic difference in the two styles of motor for the two different mounting options. If you picture both of these motors installed into a fuselage with the same orientation, meaning the prop would be mounted at the right end of the motor, the lower motor is set-up for an "X" mount and the top motor is set-up for a tractor installation. The give-away? The motor connections need to NOT rotate with the motor. The only way for the top motor's wires to be stationary is to have the right end of the motor be secured. The opposite is true for the lower motor. The lower motor is also convertible, at least this particular motor is. An adapter can be mounted to the left-side of the motor for mounting a prop and there are mounting holes in the left end of the motor to secure it. With these (brushless outrunner) motors remember, the entire outer part of the motor spins, rotating the magnets outside (hence outrunner) of the windings. This is where the magnets are mounted and the prop shaft is connected to. This is different than the inrunner motors in which the magnets rotate on the shaft, inside (hence inrunner) of the windings.
The three wires are the power connections for the motor/s. These are three-phase motors and require an ESC for brushless motors. Unlike standard brushed motors, you can connect the three wires up any way you want. If the motor spins in the opposite direction of what you want, simply disconnect any two of the wires and reverse them. This will reverse the direction that the motor rotates.