It could be also converted further to still common gram force centimeters (g-cm) by multiplying the result by 10.2, i.e. m, so the calculated torque is 1.26 mN.
mĪs the result is small usually it is expressed in milliNewton meters (mN.Efficiency may be anywhere between zero and the maximum in our example below 1000 rpm may not be the optimal speed so the for the sake of calculations you may use 10% efficiency (E = 0.1).Įxample: speed is 1000 rpm, voltage is 6 Volts, and current is 220 mA (0.22 A): Our estimated 15% efficiency represents maximum efficiency of the motor which occurs only at a certain speed. Now you can calculate the torque for this load at this speed assuming that you know efficiency of the motor. Why do you need to connect the motor to the load? Well, if there is no load – there is no torque.
#Electrical engineering calculator self made generator
Using the motor from generator kit is the best way to do it. Therefore we suggest calculating it.Įfficiency of the motor is calculated as mechanical output power divided by electrical input power:Īnd the formula for calculating torque will beĬonnect the motor to the load. Measuring the torque of the motor is a challenging task. The motors have enough torque and speed to do all kinds of experiments and calculations. This efficiency is not bad at all – it is actually much better than most of other self made designs on Internet can provide. All our kits are intended for education and not designed for real applications.
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.
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