Motor torque constant is just the motor torque divided by the armature current. This figure is usually used to determine the armature current of a motor at a particular torque. This can be obtained from the slope of a torque-current curve of a motor.
What is torque constant KT?
The torque constant, Kt, of a motor is a very useful parameter for sizing and controlling motors showing a linear speed / torque relationship. … Without getting into theoretical detail, Kt is simply the slope of the torque / current curve of a motor. The units of the constant are found in torque units per amp.
Is torque constant in an electric motor?
So electric motor torque is not constant. There is a region of operation in conjunction with the controller and for certain load conditions which will give the appearance of constant torque.
What is the K constant of a motor?
The torque constant, kT, is specific to motor’s design, including its magnetic strength, number of wire turns, and armature length. The slope of the motor’s torque-current curve is determined by the torque constant. The back EMF constant, kE, represents the relationship between the motor’s back EMF and its speed.
How do you calculate torque of a motor?
To calculate load torque, multiply the force (F) by the distance away from the rotational axis, which is the radius of the pulley (r). If the mass of the load (blue box) is 20 Newtons, and the radius of the pulley is 5 cm away, then the required torque for the application is 20 N x 0.05 m = 1 Nm.
Is DC motor speed constant?
Similarly when the load decreases, the excess torque speed ups the armature and the back emf increases. Then the motor draws less current which results in a decrease in torque and slows down to previous speed. Hence, a DC shunt motor always maintains a constant speed.
How do you use the motor constant?
To calculate the Motor Voltage Constant read the no-load speed (rpm) and convert it to radians per second. Take the Rated Voltage of the motor and divide it by the speed. To calculate the Speed Constant read the no-load speed (rpm) and convert it to radians per second. Divide this number by the Rated Voltage.
What is kv in DC motor?
Answer: “Kv” refers to the constant velocity of a motor (not to be confused with “kV,” the abbreviation for kilovolt). It is measured by the number of revolutions per minute (rpm) that a motor turns when 1V (one volt) is applied with no load attached to that motor.
What is torque in a motor?
Applied to internal combustion engines or electric motors, torque indicates the force to which the drive shaft is subjected. Torque is expressed in pound-feet (lb-ft) or newton-meters (Nm). The interaction of torque and engine speed (rpm) determines the engine power.
What is torque in AC motor?
Torque is the turning force through a radius – with the units Nm in the SI-system and the units lb ft in the imperial system. The torque developed by an asynchronous induction motor varies when the motor accelerates from zero to maximum operating speed.
What determines the torque of an electric motor?
How to calculate torque of motor: Torque is nothing but a momentary force developed at the time of force is applied to the motor. The unit of torque is N.m (Newton-meter). In other words, Torque T(N.m) is equal to the ratio between the electrical power P(W) in watts to the acceleration.
How do you find the constant of a motor?
Motor torque constant
The SI units for the torque constant are newton metres per ampere (N·m/A). Since 1 N·m = 1 J, and 1 A = 1 C/s, then 1 N·m/A = 1 J·s/C = 1 V·s (same units as back EMF constant).
Is torque constant along a shaft?
Torque — also called MOMENT OF A FORCE, in physics, the tendency of a force to rotate the body to which it is applied. … a) Torque stays constant along a shaft (so we’re neglecting any friction in bearings that hold the shaft in place).