Speed Control of Induction Motor To operate efficiently an induction motor must run with a small slip. It follows that any efficient method of speed control must be based on varying the synchronous speed of the field, rather than the slip. The two factors that determine the speed of the field, are the supply frequency […]
Generating and Braking of Induction Motor Having explored the torque–speed curve for the normal motoring region, where the speed lies between zero and just below synchronous, we must ask what happens if the speed is above the synchronous speed, or is negative. A typical torque–speed curve for a cage motor covering the full range of
Influence of Rotor Parameters on Torque Speed Curves We know that the rotor resistance and reactance influence the shape of the torque–speed curve. The designer can vary both of these parameters, and we will explore the pros and cons of the various alternatives. To limit the mathematics the discussion will be mainly qualitative, but it
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Stable Operating Regions of Induction Motor In addition to having sufficient torque to start the load it is obviously necessary for the motor to bring the load up to full speed. To predict how the speed will rise after switching on we need the torque–speed curves of the motor and the load, and the total
Variable Frequency Drive Working A variable frequency drive (VFDs) uses solid state electronic circuits to provide a signal to a motor to control its acceleration, deceleration, direction of rotation, torque, and horsepower. Drives do this by converting a fixed frequency (either 50 or 60 Hz) AC power source, to a variable frequency power supply to
Overheating is a major cause of insulation and bearing failure. 3 phase motor overheating reasons are as under: Line-Caused Motor Overheating Reasons There are four causes of line-caused overheating: overvoltage, low voltage, unbalanced voltage, and a high-resistance connection. Overvoltage: Overvoltage can cause a normally loaded motor to overheat. NEMA standard specifications allow motors a voltage
Single Phasing of Induction Motor The single phasing of three phase induction motors forms the most common hazard to motor operation, because of the possibility of overheating and burning-out of the motor under this condition. By single-phasing is meant the opening of one wire (or leg) of a three-phase circuit whereupon the remaining leg at
Hi friends, in this article, I am going to describe the linear induction motor working principle. This article will provide you answers of various questions about the LIM. A linear induction motor is a developed version of cylindrical induction motor. It is special type of induction motor which gives linear motion instead of rotational motion
The induction motor is equivalent to a rotating transformer. Hence, we can draw the induction motor equivalent circuit with the help of equivalent circuit of the transformer. The basic equivalent circuit of induction motor is shown in Fig. which is very similar to that of a transformer. Here R1 and X1 are the per phase
Hi friends, in this article, I am talking about thermal overload relay working principle and its function in a DOL starter. I hope you will find this article informative and helpful. A thermal overload relay works on the heat produced by the excessive overload current. The heat produced by the overload current is utilized to trip