In amperes measure force of electric current, in watts — electric, thermal and mechanical power. The ampere and watt in electrical equipment are connected among themselves by certain formulas, however as measure different physical quantities in them, it is simple to transfer amperes to kW it will not turn out. But it is possible to express some units through others. Let's understand as current and power in an electrical network of various look correspond.
It is required to you
- - tester;
- - current-measuring pincers;
- - reference book on electrical equipment;
- - calculator.
Instruction
1. Measure by a tester tension of network to which the electric device is connected.
2. Measure current size by means of current-measuring pincers.
3. Tension of network - a postoyannoyeumnozhta current size (amperes) on value of tension of network (volts). The received work — power in watts. For transfer to kilowatts it is necessary to divide this number for 1000.
4. Tension of network — variable to an odnofaznoyeumnozhta value of tension of network at a size of current and a cosine of the angle fi (power factor). The received work - the consumed active power in watts. For transfer of this number to kilowatts divide it into one thousand.
5. The cosine of the angle between full and active capacity is equal in a triangle of capacities to the relation of active power to full. The corner fi differently is called shift of phases between tension and current - the shift arises in the presence in an inductance chain. The cosine fi is equal to unit at purely active loading (electric heaters, glow lamps) and about 0.85 — at the mixed loading. The less reactive component of full capacity, the is less than loss therefore power factor is in every possible way sought to be increased.
6. Tension of network — variable to a trekhfaznoyeperemnozhta the size of tension and current of one of phases. Increase the received value by power factor. Similarly the power of two other phases pays off. Then, all three phase capacities develop. The received sum will also be value of power of the electroinstallation connected to three-phase network. At symmetric loading on all three phases the active power is equal to the work, phase current, phase tension and power factor multiplied by three.