If the voltage applied to the induction motor contains harmonics, then the harmonic fluxes are developed in the gap due to the magnetics of the motor. These harmonic fluxes induce e.m.f and circulate harmonic currents in the rotor windings.
Crawling and Cogging in Induction Motor Read More »
Ohmmeter is used to directly measure resistance of a device, element, circuit or any portion thereof. This meter is used to determine approximate (not too accurate) resistance of the circuit components. It can be used to measure the resistance of heating element of heater, electric iron, field coil resistance, sorting resistors used in electronics circuits. It can also
What is Ohmmeter? Construction, Circuit Diagram, Types & Working Read More »
Figure 1: Star-Star or (Y-Y) Connection. Fig. 1 shows a star-star connection of primary and secondary windings.
What is Star-Star or (Y-Y) Connection of Three Phase Transformer? Read More »
When a DC generator is loaded, the current flows through the armature winding, commutator and brushes to the external circuit. During this process, whenever a brush spans the two commutator segments, the winding element connected to those commutator segments is short-circuited. The changes in current direction, which take place in the winding part, just before,
Commutation in DC Machine (Generator or Motor) – Process & Remedies Read More »
A DC generator is the most commonly used separately excited generator, used for electroplating and battery charging. A separately excited generator is one in which the magnetic field is excited from an external DC source. The DC source may be a DC generator or a battery or a metal rectifier connected to an AC supply.
What is Separately Excited DC Generator? Circuit diagram, Characteristics & Advantages Read More »
The armature control method works on the principle that the speed of the DC motor could be varied by varying the back emf. Fig. 1: Armature Control Method of DC Motor.
What is Armature Control Method of DC Motor? Working Principle, Diagram & Applications Read More »
A constant voltage transformer (CVT) works on ferro-resonant principle. The variation in the primary flux with an unsaturated iron core does not affect the secondary flux with saturated iron core. Thus, the secondary induced voltage remains relatively independent of the voltage impressed upon the primary winding. Fig. 1: Constant Voltage Transformer (CVT).
What is Constant Voltage Transformer (CVT)? Working Principle, Diagram & Applications Read More »
A smooth variation of speed from zero to above normal with inherent stability of speed at all loads is achieved through an adjustable voltage system of speed control called Ward-Leonard Method of speed control. Fig. 1: Ward Leonard Method of Speed Control.
What is Ward Leonard Method of Speed Control? Working Principle, Diagram & Applications Read More »
Fibre Optic Cable carry light signals instead of the electric signals. They are used for light and infrared transmissions. Fig. 1: Construction of Fibre Optic Cable.
What is Fibre Optic Cable? Theory, Construction, Advantages & Disadvantages Read More »
Hot Wire Anemometer (or Thermal Flow Meter) makes use of temperature coefficient effect i.e. the resistance of conducting material changes with change in temperature. Fig. 1 : Hot wire anemometer.
What is Hot Wire Anemometer? Working, Advantages & Applications Read More »