Power Factor Correction Equipment The electrical energy is almost exclusively generated, transmitted and distributed in the form of alternating current. Therefore, the question of power factor immediately comes into picture. Most of the loads (e.g. induction motors, arc lamps) are inductive in nature and hence have low lagging power factor. The low power factor is […]
Electrical Insulation Resistance Test This test can be carried out on a complete installation, a group of circuits or on a single circuit, whichever is most suitable for the installation being tested. This test is carried out to find out if there is likely to be any leakage of current through insulated parts of the
Power in AC Circuit The instantaneous power of an AC waveform is given by p(t) = v(t) · i(t) Power in a Resistance The current and voltage are in phase on the resistor (Fig. 1). For a sinusoidal voltage, the instantaneous power is Here V and I are the RMS values of the voltage and
The term “power factor” (PF) is an expression of the relationship between the peak voltage and the peak current. Stated differently, the power factor is an expression of how far out of phase the voltage and current are to each other. What is power factor? Figure 1 shows both voltage and current peaks occurring at
Methods of Electrical Wiring Testing All new completed electrical installation should be tested before connection to the supply, to ensure that the installation is technically sound and free from any possible short circuits, etc. the main reasons, to test a new electrical installation or house wiring before it is switched on to the mains are
In this system, a delta/star-connected transformer is used. Three wires are taken from the phases and the fourth wire (i.e. neutral wire) is taken from the star point. If the voltage of each phase conductor to neutral is V then line to line voltage between the phases will be √3V. The 3 phase 4 wire
All electrical appliances and industrial equipment consume power at a lagging power factor. The power factor of industrial and commercial installations tends to be low, usually ranging between 0.60 – 0.75 only. The overall power factor of any installation is likely to be below 0.7 unless corrective measures are adopted to improve it. Due to
In ac circuits, power is measured with the help of wattmeter. A wattmeter is an instrument, which consists of two coils called the potential coil (PC) and the current coil (CC). The potential coil having high resistance is connected across the load and carries the current proportional to the potential difference across the load. The current coil
In this method of interconnection, the dissimilar ends of three phase windings are joined together i.e. finishing end of one phase is connected to the starting end of the other phase and so on to obtain a closed circuit. The three line conductors are taken from the three junctions of mesh and are denoted by R,
If the three armature coils of a 3-phase alternator are not interconnected but are kept separate, as shown in Figure below, then each phase or circuit would need two conductors, the total number of conductors, in that case, being six. It means that each transmission cable would contain six conductors which will make the whole