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Why it is dangerous to supply power to an unloaded series connected DC motor?
Starting torque becomes very high due to which motor can attain very high speed and can damage its body and connected equipments.
Is torque and current proportional?
Sometimes, for example in a separately excited dc motor. But in a series-wound dc motor the torque is proportional to current-squared, which gives the motor a very high starting torque and this makes series motors very popular for traction.
Why you use DOL starter in starting of motor?
because of starting current of induction motor is very high and it damages the insulation of motor
How speed of the repulsion motor can be reversed?
it has very high speed but no load
Why is Dc series motor used to start at heavy load?
due to its high initial torque value. the DC series motor is a Constant power motor, equal to the RATED POWER if it has at rated value of the U and I. Angular velocity=Rated Power/Torque, so Torque =Rated Power/Angular Velocity thus, in the start the velocity is zero or near, so, the Torque is infinit or very higt
What is Advantages of using a series DC motor?
The DC series motor is a high torque motor. so that it can pull heavy loads such as traction, lifts etc., the control of speed of a DC series motor is very smooth and easy.
Why dc series motor is always runs at loads?
At no load, the flux is only due to the residual flux, which is very small. the no load speed of dc series motor is very high. so the rotating part of the motor are damaged. hince dc series motor should never be run without motor.
Why it is dangerous to supply power to an unloaded series connected DC motor?
Starting torque becomes very high due to which motor can attain very high speed and can damage its body and connected equipments.
Why is dangerous to supply power to an unloaded series connected dc motor?
Starting torque becomes very high due to which motor can attain very high speed and can damage its body and connected equipments.
Is torque and current proportional?
Sometimes, for example in a separately excited dc motor. But in a series-wound dc motor the torque is proportional to current-squared, which gives the motor a very high starting torque and this makes series motors very popular for traction.
Why the series motor is started with some initial load?
In dc motors Speed is directly proportional to back emf and inversely proportional to flux i.e N∝(Eb/φ) In series motor back emf is practically constant. So if we start motor without any load Flux will be small and so speed will be very high. if we start motor without any load it will gain very high speed and may get damaged due to centrifugal forces. Series motor have very high starting torque and used where high starting torque is required.
Why is it dangerous yo supply power to an unloaded series connected dc motor?
Starting torque becomes very high due to which motor can attain very high speed and can damage its body and connected equipments.Read more: Why_it_is_dangerous_to_supply_power_to_an_unloaded_series_connected_DC_motor
Why can we start a shunt motor under no load but why can't a series motor?
The torque on a series motor is determined by the square of the armature current and, so, is very large -much larger than that of a shunt motor. Consequently, on starting, with no back-emf being generated, the torque on a series motor can be dangerously high if the machine has no mechanical load.
Why should a series motor always start with a load?
In any DC motor the speed depends inversely on the flux. Consider when starting a series motor the current flowing will be high, but the flux that the motor produces will be moderate since the series winding has less number of turns. If u start the motor without load the speed will increase. as speed increases the back emf increases. this decreases the current through the series winding and hence flux decreases and the speed further increases. Theoretically speaking the speed becomes infinite. But practically the motor will accelerate to very high speed , which will damage the motor. But if you start the motor with the load, you are actually reducing the starting speed hence the motor runs safely. Since series motors has this property it is used in trains to pull high load.
Why dc series motor is never started on light load?
the speed N is inversely proportional to armature current I. At light loads this current is very small. Hence motor will run at very high speed when started on no load/light load.........
Why you use DOL starter in starting of motor?
because of starting current of induction motor is very high and it damages the insulation of motor
Who to find out infinty speed of dc series motor?
A series dc motor does not have a well defined maximum speed, which depends on the friction in the bearings. It is dangerous to run this type of motor without a load because it could be damaged by excessive speed. Series motors are normally attached to massive loads, like trams or trains, which limits the speed, and the very high starting torque is useful for traction because it removes the need for a gearbox.
