In this article we will learn about the starting of slip ring induction motor . We will discuss in details about the how induction start. We will study about the rotor resister starting.
Starting of Slip Ring Induction Motor
Now we are going to discuss about the starting of slip ring induction motor.
Three phase induction motor are self starting in nature when 3-phase supply is given the rotor individually start rotating due to R.M.F
In the slip ring induction, motor rotor resistance starting is very useful method. These are some method starting of slip ring induction motor.
Rotor Resistance starting
In this method, which is applicable to slip ring, motor only? The motor speed is reduced by introducing external resistance in the rotor circuit. For this purpose, the rotor starter may be used provided it is continuously rated. This method is in fact similar to armature rheostat control method of DC shun motors. Near synchronous speed, it is obvious that for a given torque, slip can be increased. Speed can be decreased by increasing the rotor resistance. It is basic method of starting method of slip ring induction motor.
Breaking method of slip ring Induction motor
The principle involved in to produce negative torque while plugging the phase sequence is reversed which make the rmf to reverse and consequently the motor reverses the reason of plugging slip greater than one. This produced high temperature rise and the motor has to bee designed to withstand. Other disadvantage due to the motor may operate the reverse direction. If the mechanical breaking is not applicable.It is also describe above article which is starting of slip ring induction motor.
The above two disadvantage are rectified in this method. Disconnect the stator from the supply and apply a suitable DC voltage across the stator, any two terminals which produced a constant flux and will not make the rotor rotates as there is no flux reversal no temperature rise as well as there is no danger of motor reversing. It is also describe of starting of slip ring induction motor.
It is not stop the motor but occurs naturally when the motor is subjected to over. Including modes like fraction etc. when the speed increases torque become negative and produced a breaking, which do not stop but control the speed. As it occurs naturally which is automatic very advantage in railways.
Hence these are some starting method of slip ring induction motor.From above article we have studied about the different types of breaking like regenerative breaking,plugging etc. We have studied about rotor resistance starting method.