Motors built from our kits usually have maximum efficiency of about 15% (see Experiments section on how we estimated this).ĭon’t be disappointed with 15% maximum efficiency. Even precision made small industrial motors such as one we use as a generator in generator kit have maximum efficiency of 50-60%. If the motor has 100% efficiency all electrical power is converted to mechanical energy. Rpm – rotational speed in revolutions per minute

Where ω – angular speed, measured in radians per second (rad/s) It is easy to calculate angular speed if you know rotational speed of the motor in rpm: Ω – angular speed, measured in radians per second (rad/s). Where P out – output power, measured in watts (W) Output mechanical power of the motor could be calculated by using the following formula: It is motor speed and torque – the turning force of the motor. Motors supposed to do some work and two important values define how powerful the motor is. V – applied voltage, measured in volts (V). Where P in – input power, measured in watts (W) The consumed electrical power of the motor is defined by the following formula: For any given resistance (in the motors it is basically the resistance of the coil) this formula explains that the current can be controlled by applied voltage. You may calculate the resistance of your motor by measuring the consumed current and applied voltage. This formula could be used in many cases. V – applied voltage, measured in volts (V)

Where I – current, measured in amperes (A)

It states that current through the conductor is directly proportional to applied voltage and is expressed as: One of the most important laws of physics is the fundamental Ohm’s Law. This is modern metric system that is officially accepted in electrical engineering in the USA. We will use the International System of Units (SI). It is very important to measure different electrical and mechanical parameters of your motor and calculate unknown values using the following helpful formulas. Good science project does not stop with building a motor.

Ac motor winding formula calculator