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Why no load speed is highest in series motor?
Explanation: At no load, armature current tends to zero, flux φ tends to zero, where speed is inversely proportional to the flux, speed will tend to infinity. Thus, no load speed of DC series motor is highest.
What is no load speed?
The no-load speed is the maximum speed a cordless screwdriver can reach without a load. (When it’s not driving screws or drilling holes). Manufacturers give the tool’s speed at no-load because once the screwdriver begins driving screws or drilling, its maximum speed will vary depending on how demanding the task is.
Why DC motors have abnormal speed at no load?
Speed of DC Series Motor ωm = Very high, which is also clear from the Speed Current Characteristics of DC Series Motor as shown in figure above. Therefore if the DC Series Motor is started at No Load then the speed of DC Series Motor will become dangerously high which will definitely damage the DC Series Motor.
What is the no load speed of the motor?
No Load Speed: Speed of a motor (ω [rad/s]) with no load applied. This can also be described as the maximum speed of the motor. Stall Torque: The amount of torque (τ [Nm]) needed to fully stop the rotation of the motor.
What is no load and full load?
In simple words, full load of a machine is the rated power output as per machine name plate whereas no load means zero power output. In case of electric motors and generators, the following may serve as an elaboration: Motor: A motor takes electrical power input and delivers mechanical power output at its shaft.
Why series motor is never started on no load?
A series motor should never be started at no load. With no mechanical load on the series motor, the current is low, the counter-EMF produced by the field winding is weak, and so the armature must turn faster to produce sufficient counter-EMF to balance the supply voltage. The motor can be damaged by overspeed.
Which motor should not be started at no load?
As field current is zero so field flux becomes zero. As speed of a motor is inversly proportional to field flux, so speed tends to infinity i.e, the case if dangerously high speed of DC SERIES MOTOR at no-load.
How do you find no load speed?
In most cases, you can look inside the motor and count the number of poles in the winding; they are distinct bundles of wire evenly spaced around the stator core. The number of poles, combined with the ac line frequency (Hertz, Hz), are all that determine the no-load revolutions per minute (rpm) of the motor.
What is no load speed of motor?
The no-load speed of a DC motor is the speed that the DC motor will turn when nothing is attached to its shaft. This is why it is called no load. The DC motor isn’t loaded with an object. When a DC motor has nothing attached to its shaft, it is able to operate at its highest maximum speed.