Power is a physical quantity which is equal to the relation of the work performed for some period to this period. It is measured in watts; joules divided into second; horsepowers. Power happens four types: instant, active, reactive and full. Have a capacity: powerful electric motor, powerful explosion. Upon purchase of any device it is necessary to know its power. For example, copper power for heating calculation.
It is required to you
- Wattmeter, phasemeter, ampermeter, voltmeter, calculator.
Instruction
1. Instant power. That to find it, multiply instant values of tension and current on any site of an electrical circuit. If the site of a chain contains the resistor with an electrical resistance, then instant power is equal to the work of instant value of current on this site of a chain in a square on the electrical resistance of this resistor or private instant value of tension in a square to resistance.
2. Active power is an average for the period value of instant power. That to find it, increase the operating values of tension and current by a cosine of the angle of shift of phases between them.
3. Reactive power is a size which characterizes the loadings created in electrotechnical devices by fluctuations of energy of the electromagnetic field in a chain of sinusoidal alternating current. That to find it, increase the operating values of tension and current by a sine of the angle of shift of phases between them.
4. Full capacity. That to find it, multiply the operating values of periodic electric current in chains and tension on its clips. For this purpose determine current by the ampermeter, and tension by means of the voltmeter.
5. Also to determine the power of electric current or electromagnetic signal, use such measuring device as a wattmeter. And such electric device as the phasemeter will help you to define the angle of shift of phases between two changing periodically electric fluctuations, for example, in the three-phase power supply system. And then you cannot find power.
6. Remember! When determining power be extremely careful with all electric devices which are in a chain, connect a chain correctly.