how to calculate resistance box for slipring motors
To calculate the resistance for a slip ring motor, there is an equation that must be solved. This is Torque = S/R. S is the slip of the motor and R is the resistance of the motor.
Ac motor have slip ring, to remove the slip ring,connected to the commutator its a dc motor.
ring is dirty or brushes arent seated
The stator coil is exactly the same as a 3 phase induction motor. The difference being the rotar which has 3 phase wiring in star point or delta connection and also has the sliprings connected to the wiring of the rotor. Brushes are use for the contact between the surpply and the rotor. By controling the current we can control the torgue and speed of the motor. This is done with resistance. Resistance can be greated by means of a resistance bank, liquid resistance or a variable resistance. The basic Idee is: The higher the resistance, low starting current, high torque, high % slip. Motor runs slowlyLow resistance , Higher starting current, lower torgue, lower % slip Motor runs faster.Thus by varing the rotor resistance the motor can be adapted for a spesific load.The motor Are mainly used for Overhead cranes, Elevators in buldings, Pumps under pressure and large fans
DOL(Direct Online starting) Star Delta starting Auto transformer starting Above methods are for squirrel cage induction motor Rotor resistance starting is used for wound rotor or slip ring induction motor
Both have 3 a phase stator winding, the squirrel cage has a rotor with bars arranged around it's periphery, these bars are joined at both ends by a continuous ring. This forms a closed circuit of low resistance which is fixed. The wound rotor (slip ring motor) is similar in construction but the bars are replaced by copper windings, similar to those in the stator. They are star connected and the three ends are brought out to slip rings which allow an electrical connection to be made to the outside world. When no connection is made between these ends and the stator is energised, little current flows in the stator which does not turn, but when some resistance is inserted, current flows in the stator windings and the rotor rotates. As the rotor gains speed the resistance is taken out of circuit and the slip rings shorted together. The motor runs as a cage induction motor.
Yes a slip ring motor is there. There is a slip ring and a brush in the motor to add external resistance to the motor inorder to be able to control its speed.
it is related to Slip ring rotor max.currents and voltage ...
Combination of water and caustic soda for improving the resistance in starter, that's called Liquid Resistancestarter.If any slip ring Induction motor, at the time of startinggiven the external resistance required to rotor side, why because starting current and starting torque is very high.So we are using resistance starter depend on motor capacity , at that place using Liquid resistance starter.Liquid resistance starter (LRS) ,IN which externalresistance is liquid media which is use for the startingmethod of slip ring motor. For starting of slip ring motor external resistance arerequired so that we use liquid (addition of some causticsoda)as resistance so that is called as LRS.
Ac motor have slip ring, to remove the slip ring,connected to the commutator its a dc motor.
A three phase motor will not start if one phase leg is open.
ring is dirty or brushes arent seated
rotor contactor are used to cut the resistance in slip-ring motor connected through resistance box. resistance is proportional to torque. so by controlling rotor contactor resistance can be controlled and hence torque can be controlled. for more information check torque and speed characteristic of wound motor.
short the rotor terminals.
The stator coil is exactly the same as a 3 phase induction motor. The difference being the rotar which has 3 phase wiring in star point or delta connection and also has the sliprings connected to the wiring of the rotor. Brushes are use for the contact between the surpply and the rotor. By controling the current we can control the torgue and speed of the motor. This is done with resistance. Resistance can be greated by means of a resistance bank, liquid resistance or a variable resistance. The basic Idee is: The higher the resistance, low starting current, high torque, high % slip. Motor runs slowlyLow resistance , Higher starting current, lower torgue, lower % slip Motor runs faster.Thus by varing the rotor resistance the motor can be adapted for a spesific load.The motor Are mainly used for Overhead cranes, Elevators in buldings, Pumps under pressure and large fans
yes
DOL(Direct Online starting) Star Delta starting Auto transformer starting Above methods are for squirrel cage induction motor Rotor resistance starting is used for wound rotor or slip ring induction motor
Slip Ring Induction Motor and Squirrel Cage Indution Motor