The power factor of an AC electric power system is defined as the ratio of the real power flowing to the load to the apparent power,[1][2] and is a number between 0 and 1 (frequently expressed as a percentage, e.g. 0.5 pf = 50% pf). Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power can be greater than the real power.
In an electric power system, a load with low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.
Linear loads with low power factor (such as induction motors) can be corrected with a passive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system. In such cases, active or passive power factor correction may be used to counteract the distortion and raise power factor. The devices for correction of power factor may be at a central substation, or spread out over a distribution system, or built into power-consuming equipment.
The symbol of phase sequence is RYB
Power factor measures the phase difference between voltage and current. If they are in phase the Power Factor is one. If the current and voltage are out of phase the power factor is between zero and one. You can describe the PF by saying the current lags the voltage with a PF = .8 or the voltage leads the current with a .8 PF.
motor is designed to operate in forward and reverse direction for the purpose of elevator. Phase sequence protection is not required.
The power factor depends on the phase angle between the voltage and current on a conductor. The amplitude of the current has no effect on it.
The potential of each line of a three-phase system is displaced from the other two by 120 electrical degrees. The sequence, or order, in which the potential of each line reaches its peak value is termed the 'phase sequence' of the system. The 'normal' phase sequence of an alternator is considered to be the 'positive phase sequence', is arbitrarily assigned colours (e.g. red-yellow-blue, etc.), numbers (e.g. 1-2-3), letters (e.g. A-B-C), or a combination of letters or numbers (e.g. L1-L2-L3). If that alternator should run backwards, or (far more likely) if its terminals were disconnected and then incorrectly reconnected, the the sequence would be A-C-B (etc.), which would be considered to be 'negative phase sequence'. Before connecting two generators (or two complete transmission/distribution systems) together, their phase sequence must be confirmed as being the same. Reconnecting a three-phase motor with the wrong phase sequence would result in it running in the reverse direction and, possibly, damaging its load.
Relation between phase difference and path difference is path difference/wavelength=phase difference/2*pi
No. It depends on the inductive and capacitive reactance of the load.
The order in which the voltage of the coil reaches to the maximum value is called the Phase Sequence.POSITIVE PHASE SEQUENCE: If the coil is rotated in anticlockwise direction, the phase sequence will be Positive Phase Sequence, i.e., R-Y-B or A-B-C.NEGATIVE PHASE SEQUENCE: If the coil is rotated in clockwise direction, the phase sequence is called Negative Phase Sequence, i.e., R-B-Y or A-C-B.NOTE: Phase Sequence is of great importance in parallel operation of three phase transformers and alternators.
The symbol of phase sequence is RYB
How Negative phase sequence relay work
The fields are in time phase and space quadrature.
The phase of the moon depends on it position in relation to the earth and the sun. For instance, when the moon is in between the earth and the sun, this is the new of full moon phase.
Power factor measures the phase difference between voltage and current. If they are in phase the Power Factor is one. If the current and voltage are out of phase the power factor is between zero and one. You can describe the PF by saying the current lags the voltage with a PF = .8 or the voltage leads the current with a .8 PF.
Strategic planning is the first phase of project selection.
Interphase## G1SG2ProphasePrometaphaseMetaphaseAnaphaseTelophaseMitosisCytokinesis
Power factor capacitors can be installed on a three phase motor between the motor contactor and the overload heater block.
Power factor is the cosine of the phase angle between voltage and current. It is also KW/KVA.