LITERATURE REVIEW (FYP 1)

JOURNAL 3


DC MOTOR

A DC motor has a two wire connection. All drive power is supplied over these two wires think of a light bulb. When you turn on a DC motor, it just starts spinning round and round. Most DC motors are pretty fast, about 5000 RPM (revolutions per minute).

With the DC motor, its speed (or more accurately, its power level) is controlled using a technique named pulse width modulation, or simply PWM. This is idea of controlling the motor’s power level by strobing the power on and off. The key concept here is duty cycle the percentage of “on time” versus“off time.” If the power is on only 1/2 of the time, the motor runs with 1/2 the power of its full-on operation.

If you switch the power on and off fast enough, then it just seems like the motor is running weaker there’s no stuttering. This is what PWM means when referring to DC motors. The Handy Board’s DC motor power drive circuits simply switch on and off, and the motor runs more slowly because it’s only receiving power for 25%, 50%, or some other fractional percentage of the time.

Credit to : Prajapati Dipali, K., Raj Roshani, D., Patel Komal, C., & Hilali Marhaba, A. ( 2014). Automatic Gate Opening System For Vehicles With RFID or Password.