Torque Speed Curve Induction Motor

November 07, 2024 Post a Comment

Torque speed curve induction motor

The torque speed curve of a load is a plot showing its torque requirement on the y- axis versus the speed on x-axis. It's the torque requirement of the load from zero speed to full speed. Its application/load specific and varies with different load types.

How is torque and speed related in induction motor?

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 torque slip curve of induction motor?

Hence, for intermediate values of the slip, the torque-slip characteristics is represented by a rectangular hyperbola. The curve passes through the point of maximum torque when R2 = 𝑠𝑋2. The maximum torque developed by an induction motor is known as pull-out torque or breakdown torque.

What are the torque speed characteristics of induction motor?

The torque-speed characteristics of a three-phase induction motor is a straight line between the no-load and full-load operating points. The slope of the curve line depends upon the resistance of the rotor circuit i.e. the higher the rotor circuit resistance, the sharper the slope of the curve.

Why is the torque-speed curve important?

plots the torque of a motor against the speed the motor is going at. The relationship between speed and torque varies dramatically across different types of motor and also between manufacturers.

How do you draw a torque-speed curve?

Torque/Speed Curves

The curve is for the output of the gearbox.
The units given on the graph are N·m for torque, and rpm for rotational speed.
no load speed, = 600 rpm.
stall torque, = 0.325 N·m.
max power output, (P_max= [31.416 rad/s * 0.163 N·m] = 5.105 W) occurs at = 300 rpm, and = 0.163 N·m.

Why does speed decrease as torque increases?

Since the rated output power of a motor is a fixed value, speed and torque are inversely related. As output speed increases, the available output torque decreases proportionately. As the output torque increases, the output speed decreases proportionately.

What happens to torque when you increase speed?

The torque and speed relationship is inversely proportional since the rated output power of a motor is a fixed value. As output speed increases, the available output torque decreases proportionately.

Why does torque increase when RPM increases?

According to Newton's second law, the summation of torque=Moment of inertia * Angular Speed (RPM). As the moment of inertia is constant, the torque is proportional to the angular speed. Therefore, If the the RPM increases, the torque increases.

What is the relationship between torque speed and torque slip?

As the slip increases, the speed of the motor decreases with the increase in load. The term (sX 20) 2 becomes large. Hence for heavy loads, torque is inversely proportional to slip.

What is the shape of torque slip curve?

The torque-slip characteristics is represented by a rectangular hyperbola.

What is torque slip?

Torque-slip Characteristics The slip is defined as a ratio of synchronous speed and the actual speed of the rotor. The actual speed of the rotor varies with loading condition. Therefore, the slip changes with loading condition. In the previous article, we have derived the torque equation of an induction motor.

Which curve best describes torque speed characteristics?

Pull-in Torque curve (inertial load): This curve represents the maximum torque and speed combination that a stepper motor with an inertial load (i.e. damper) can supply to a load and start or stop without any acceleration or deceleration.

What is the speed of 3-phase induction motor?

If it is a 2 pole motor, its synchronous speed is 3600 RPM. In order to cut the synchronous speed in half to 1800 RPM, the control would supply 115 V, 30 Hz, which maintains the V/f ratio of 3.83. This method of control still allows slight variations of speed due to changing motor loads.

What is slip curve?

Slip Curve can be used to model the slip in situations such as a wheel ground contact. It computes the slip for two given speeds and assigns a friction coefficient according to the specified slip characteristic.

Why does torque decrease with RPM?

At high RPM, torque drops off primarily from intake and exhaust flow restriction. Volumetric Efficiency declines because the engine can't breathe any faster. Mechanical efficiency also declines at higher RPM, due to increased frictional resistance. This further reduces torque at the output.

Why do electric motors lose torque at high RPM?

When the rotor rotate, there is a change in magnetic flux, causing what we call back EMF. This back EMF “oppose” the voltage we applied to the motor, thus reducing the current in the winding. Higher RPM means higher rate of change in magnetic flux, means lower current and torque.

How is torque calculated in an induction motor?

Torque of a three phase induction motor is proportional to flux per stator pole, rotor current and the power factor of the rotor. T ∝ ɸ I2 cosɸ2 OR T = k ɸ I2 cosɸ2 .

What is a speed curve?

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How do we calculate torque?

A practical way to calculate the magnitude of the torque is to first determine the lever arm and then multiply it times the applied force. The lever arm is the perpendicular distance from the axis of rotation to the line of action of the force. and the magnitude of the torque is τ = N m.