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It's amazing to see how far electric motor technology has come over the years. From closed end bell 540-size Johnson or Mabuchi motors to open end bell hand-wound modified motors, and now brushless motors, it's amazing to see just how far motor technology has come. With all the different types of motors and technologies in use, things can get quite confusing. We're here to help demystify motor tech and provide the answers you'll need in understanding your electric motor system. In addition, we've also put together a comprehensive list of terms below to help you better understand the different technologies out there, how they work and what this all means to you.
Armature—The central component in a brushed motor. The commutator, stack and windings are all mounted to the armature.
Brushed Motor—An electric motor that utilizes brushes rubbing against a commutator to transfer electrical current to create rotation. Brushed motors are inexpensive to produce, but require frequent maintenance to ensure the motor will continue to perform at a high level.
Can—The main "body" of an electric motor. The can houses the magnets in a brushed motor and the stator in a brushless motor.
Closed End Bell Motor—A brushed motor that is not designed to be readily serviced. Closed end bell motors tend to have shorter life spans compared to open end bell motors due to the fact that the commutators and brushes cannot be easily cleaned or replaced.
Commutator (A.K.A. Comm)—A rotary electrical switch in brushed motors. The commutator is copper in color, mounted to the top of the armature and features three segments. The brushes ride against the commutator and transfer current to generate rotation.
End Bell—The top-most portion of a motor. On a brushed motor, the end bell houses the brushes, brush springs, a bearing or bushing and, often, some sort of capacitor.
Kv—A rating of performance for brushless motors. While Kv ratings are occasionally applied to sensored motors, sensorless brushless motors are almost always rated by Kv. The higher the Kv rating of a motor the faster it will be. Kv refers to the number of RPM a motor will produce for each volt of power input to it For example a 1,000Kv motor would produce roughly 7,400 RPM at 7.4 volts.
Open End Bell Motor—A brushed motor that has been designed in a way to allow you to service and clean the commutator, replace the brushes and the springs. Some open end bell motors, known as rebuildable, also allow you to completely remove the end bell, making it possible to completely remove armature from the can for easier maintenance or replacement.
Sensored Brushless Motor—A type of brushless motor that utilizes special sensors, called Hall Effect Sensor, to connect the motor to the Electronic Speed Controller. The purpose of this sensor wire is to allow the Electronic Speed Controller (ESC) to better monitor the position of the rotor in relation to the stator to provide smooth and consistent throttle response. Sensored motors are used for sanctioned racing and are rated in turns.
Sensorless Brushless Motors—A type of brushless motor that does not use any sort of Hall Effect Sensors to connect the motor to the Electronic Speed Controller (ESC). Due to the simpler construction and design, sensorless brushless motors are less expensive. Sensorless motors are generally rated in Kv. The higher the Kv rating, the faster the motor will be.
Stator—The "can" of a brushless motor. The stator is the part of a brushless motor that houses the windings.
Turn (A.K.A. Wind)—The number of times a length of wire is wrapped around a stack in a brushed motor or the stator in a brushless motor. The more turns a motor has, the more wire was used in its construction. Having more wire not only increases the rotating mass of a brushed motor's armature, but also increases the resistance, reduces efficiency and slows the motor down. The lower the turn of the motor (generally speaking) the faster it will be.
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