Which motor does not start at no load condition?
This can be seen from the speed-armature current and the speed-torque characteristics that on low armature current and low torque condition motor shows a tendency to rotate with dangerously high speed. This is the reason why series motor should never be started on light loads or no load conditions.
Which of the following motor should not be started on no load?
Since speed is constant and torque (τ) is proportional to armature current (Ia). So that, starting a shunt motor at a heavy load requires a high starting current. In order to avoid this high starting current, shunt motors are not started at heavy loads and they should be started without any load.
Which motor is used at no load?
No Load Test is an indirect method used for determining the efficiency and also to determine the circuit parameters of the equivalent circuit of the three-phase induction motors. The open-circuit test is performed on the transformer. The no-load test is the same as the open-circuit test performed on the transformer.
Which DC motor should not be started without load?
The DC series motor attains dangerously high speed when we run it on no load. The main reason of over speeding is that at no load the flux produced by the field winding is very less and the reduced flux cause over speeding of the motor.
Which motor can be started on no load Mcq?
Explanation: DC series motors are used in those applications where high starting speed is required at its initial phase. Since no load operation speed of DC series motor is very high, it is always operated on some non-zero load.
Why single phase AC motors are not self starting?
Single phase induction motor has distributed stator winding and a squirrel-cage rotor. When fed from a single-phase supply, its stator winding produces a flux ( or field ) which is only alternating i.e. one which alternates along one space axis only. … That is why a single phase motor is not self-starting.
Why does Series motor start with load?
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.
When a DC motor has no load what will happen to the back emf?
The back emf is represented as a variable emf that opposes the one driving the motor. Back emf is zero when the motor is not turning, and it increases proportionally to the motor’s angular velocity.