What is the relation between torque and current in induction motor?

If the question is about the relationship between induction motor current and shaft torque around full load current, then the torque is almost directly proportional to the current or vice versa.

Is there any back EMF in induction motor?

Induced EMF in the rotor of the Induction motor can be called as Back EMF, which is analogous to back EMF of the DC motor. However there is a difference in the effect of back emfs of Induction motor and DC motor. In DC motor at the starting the back emf is zero, while in Induction machine Back emf is maximum.

What causes high amps on motors?

What Causes a Motor to Draw Higher Amps? Motors require a certain output in watts in order to function, and this is the result of a voltage multiplied by amps. So when voltage falls, resistance scales up in order to supply the difference, and the motor will also draw more current.

What is starting torque in induction motor?

Locked Rotor or Starting Torque The Locked Rotor Torque or Starting Torque is the torque an electrical motor develops when starting at zero speed. A high Starting Torque is more important for application or machines hard to start – like positive displacement pumps, cranes etc.

What is torque current in induction motor?

Induction Motors An induction motor develops torque by inducing current to the rotor, which is proportional to the differential speed of the rotor and the rotating magnetic field in the stator. For NEMA design B motors the differential speed (called slip) is between 1\% and 2\% at full load.

What is induced emf in induction motor?

When 3 phase voltage applied across the stator winding for starting of induction motor, high inrush currents magnetize the air gap between the stator and rotor. An induces emf is generated in the rotor windings of the induction motor because of the rotating magnetic field. This induced emf produces electrical current in rotor windings.

Why does the primary current increase in an induction motor?

Thus the primary current severely increases. This is why it is famously said “The secondary of current transformer should not be open while running condition”. Induction motor acts like an Electrical transformer, thus there is high starting current So at starting condition, the resistance of stator is relatively low compare to the reactance.

What is inrush current in an induction motor?

When an electrical device, such as an AC induction motor, is switched on, it experiences a very high, momentary surge of current, referred to as inrush current. When an AC induction motor is started, the supplied voltage creates a magnetic field in the stator, which induces a magnetic field in the rotor.

Does the speed of a motor affect the amount of EMF?

However, the amount of back EMF produced is directly proportional to the speed of the motor. So at startup — when the motor speed is near zero — there is very little back EMF, and high “inrush” current is allowed to flow. The amount of current drawn by the motor during startup is also influenced by the resistance of the stator windings.

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