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Why do you use capacitors on fan motors or blowers?
We use capacitor on fan motor or blower to create phase difference between two winding(Starting & running). This phase difference introduce starting torque on fan motor. Otherwise without capacitor the torque produced in positive Half cycle of AC supply is nullify by the torque produced in negative half cycle.
Why synchronous motors does not have starting torque?
Becoz it use frequecy to start
Where theSlip ring induction motors are used?
The slip ring induction motors are usually used in the application requiring the low starting current or the high starting torque.
Why ac motors are not used in railways?
Ac motor has a low starting torque so that DC series motor used in railways cause DC motor has high starting torque
Which motor has high starting tourque?
Series motors have the highest starting torque. The torque is proportional to the square of the current, and the starting current is so high it has to be limited by a resistor called a rheostat. Series motos are used mainly on trams and trolley buses.
What is the difference between dynamic torque and static torque ratings?
One difference between dynamic torque and static torque is the level of difficulty to measure. Static torque is each to measure, while dynamic torque is not. This is because it requires a transfer of an electric or magnetic effect.
Why do some induction motors start at no load?
The motor might produce little torque when starting. Single-phase motors are particularly bad in this regard. So it is often necessary to remove the load while starting. Loads like fans or rotary driers do not need the load taking off while starting, because the demanded torque is small at low speeds.
Drawing of speed-torque curve for synchronous machine?
Theoritical torque speed curve for a synchronous machine will be a vertical line located vertical to the synchrounous speed at x axis, from starting torque to stalling torque value. This is because theoritically synchronous motors are not self starting. Practically however they start as induction motors and at near synchrounous speed the excitation is switched on. Anand Sekhar
In what sense dc motor is better than ac motor?
DC motors can spin at a much faster speed and have higher starting torque.
Why DC motors are self starting?
As magnetic field of dc motor is constant. Whenever a current is given to rotor winding there will be a magnetic flux in air gap between rotor and winding so there will be torque in rotor of f=ibl. so due to this torque rotor get rotate and get started.
What difference between running torque and starting torque?
Torque is the the force required to move a body about its fulcrum. The starting Torque is the force required to move the body from 0 rpm to the stipulated rpm, the Running torque is the force required to maintain the rpm. The Starting torque is often higher than the running force. Imagine peddling a push bike with one gear (say the one gear is a high gear), the force required to set off will be relatively high in comparison to the force you exert in order to maintain a velocity.
What is difference between speed and torque?
speed= distance per seconds & torque= revolution per seconds
