In case at attentive inspection of the case of the electric motor it was not succeeded to find value of its power, calculate it independently. For calculation of power consumption measure current on windings of the rotor and by means of a formula find the power consumed by the electric motor. It is possible to determine electric motor power, knowing its design and dimensions. For calculation of useful power of the electric motor find the frequency of rotation of its shaft and moment of force on it.
It is required to you
- current source, the ampermeter, line, the table of dependence of a constant of engine C on number of poles, dynamometer at the stand.
Instruction
1. Determination of engine capacity on a tokupodklyuchita the engine to a source of current and the known tension. After that, turning on the ampermeter in a chain of each of windings, measure working current of the engine in amperes. Find the sum of all measured currents. Increase the received number by value of tension, power consumption electric motor in watts will be result.
2. Determination of power of the electric motor on its gabaritamizmerta the internal diameter of the core of the stator and its length together with air ducts in centimeters. Learn the frequency of the alternating current main in which the engine and also the synchronous frequency of rotation of a shaft is connected. For definition of a constant of polar division increase the work of diameter of the core on the synchronous frequency of a shaft by 3.14 and consistently divide into the frequency of network and number 120 (3.14•D•n/(120 · f)). It will be polar division of the car. Find quantity of poles, having increased by the 60th frequency of current in network and having divided result into the frequency of rotation of a shaft. Increase result by 2. On these to data for determination of dependence of a constant of engine C on number of poles find value of a constant in the table. Increase this constant by a square of diameter of the core, its length and synchronous frequency of rotation, and result increase by 10^(-6) (P = C•D ²\• l· n·10^ (-6)). Receive value of power in kilowatts.
3. Determination of the power given to an elektrodvigatelemnaydita own speed of rotation of a shaft of the engine by the tachometer in revolutions per second. Then define traction effort of the engine by a dynamometer. For obtaining value of output power in watts increase rotation frequency by number 6.28, by value of force and radius of a shaft which measure by a ruler or a caliper.