The defining characteristic for any engine and the majority of devices is their power. Often it is specified in technical documentation to the device. If she does not manage to be found, determine this size independently. If power is measured in horsepowers, transfer it to kilowatts and watts.
It is required to you
- Tester, speedometer, radar, stop watch
Instruction
1. To determine the power consumption of any electric device, connect to it in parallel a tester, turn on the device in network with a source of current and measure tension consumed by it in volts. Then switch a tester to measurement of current and connect it in a chain consistently with the device. Measure current in a chain in amperes. Calculate power consumption, having found the work tension on P=U*I current. Receive result in watts.
2. In case it is necessary to measure electric motor power, measure current on each winding separately, then put results. The further sequence of actions remains the same.
3. If the electrical resistance of the device is in advance known, and also rated voltage with which it works then calculate its power, without measuring anything. For this purpose divide a square of rated voltage into P=U device resistance²/R. As a result receive rated power in watts.
4. In the course of work the internal combustion engine of the car reduces the power (wears out). To find it, determine the mass of the car by technical documentation. Fill in in it a number of fuel, in advance having found its weight. Weigh the driver who will carry out test. Find the total mass of the car, fuel and the driver.
5. Disperse the car for the shortest period up to 72 or to 108 km/h (depending on characteristics of a car). Control result or by means of an exact speedometer or the special radar. At the same time measure time for which dispersal was made. Find car power, having increased lump by a speed square, having divided result into 2 and for the period of dispersal of P=m*v² / (2*t). Speed when calculating take 20 m/s for 72 km/h and 30 m/s for 108 km/h.
6. To translate the power given in horsepowers to watts increase this number by 735. To transfer result to kilowatts, divide it for 1000.