Electromechanical reduced-voltage starters must make a transition from reduced voltage to full voltage at some point in the starting cycle. At this point there is normally a line current surge. The amount of surge depends on the type of transition used and the speed of the motor at the transition point. Figure 1 illustrates typical …
AC and DC motors come in many shapes and sizes. Some are standardized electric motors for general-purpose applications. Other electric motors are intended for specific tasks. In any case, electric motors should be selected to satisfy the requirements of the machines on which they are applied without exceeding rated electric motor temperature. Motor Selection Criteria …
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 …
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. Causes of Single Phasing of Induction Motor The single phasing of induction motor can occur because of causes external to the motor which are It …
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 …
Auto transformer starters are used generally with AC squirrel cage motors having a power rating of more than 20 HP. Motors of these power ratings draw excessive starting current with the use of Star/Delta starter. This may cause excessive strain on the motor and creates an intense voltage dip. This can prove harmful for the motor …
Hi friends, in this article, I am discussing the vfd working principle and hope you will find it very help full and informative. The squirrel-cage induction motors are the most common three-phase motors used in industrial applications. The preferred method of speed control for squirrel-cage induction motors is to vary the frequency of the supply voltage, and the system …
