Mell What will happen to a DC series motor when its load is removed?
What occurs if the load is removed from an operating series DC motor? It will stop running. Speed will increase slightly.
Why do DC series motors start loading?
At the starting of the motor there is no back emf, so large current current flows cause high starting torque. This starting torque leads to very fast acceleration of motor if shaft is not connected to any load. This fast acceleration cause motor to damage. So series motor are always started with load.
What is the ideal no load speed for a DC 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.
How do you reverse a DC motor?
- The direction of a DC compound motor can be reversed by changing the polarity of the armature coil or the field coil.
- We can reverse the direction by simply reversing the armature leads.
- Generally changing direction of field is easier, because it carries lesser current as compared to armature current.
Why is DC series motor should not be started without 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.
What happens to a DC motor when it loses the field?
When you lose the field, theoretically, the speed is infinity and in practice, the motor will reach the speed whence it will destroy itself in the absence of protection to prevent such events. The three main types of DC motors are: Permanent Magnet, Shunt wound, and Series wound.
What are the disadvantages of series wound DC motors?
Series DC motors, when their output shaft is unloaded, will continue to accelerate until they destroy themselves. This is a consequence of wiring the field winding in series with the armature, and is the most concerning disadvantage of these motors.
What happens to a motor when there is no load?
The motor will speed up to its no-load speed, which may damage the motor. At no-load, the load is actually whatever friction is in the motor such as from bearings, brushes, and air resistance. This friction mostly heats the motor. The motor will speed up to its no-load speed, which may damage the motor.