Resistance of stator winding is the resistance of the copper conductors being used for building the windings of three separate phases, i.e. R-Y-B. These windings are marked like U1-U2, V1-V2 & W1-W2 at the motor terminals (6 nos.) for the three phases, i.e. R-Y-B respectively. We have simply to measure the resistance of each winding by using a multimeter by connecting the terminals (2 no.) to U1 & U2 and so on.
The resistance should be in ohms not milliamps [amps is form of measuring current not resistance] milliamps to microamps in case of large motors, it may be in amps in case of small sized motors. But resistance of each winding should be nearly same to each other. This shows the electrical balance among windings & also proves the healthiness of the winding.
The winding resistance is measured by an ammeter and volt meter .
resistance - v/i
the resistance of a motor winding should be very small (1>)
The resistance of a field winding doesn't measure anything. It's used to determine the voltage that should be applied to the field winding to generate a specific field current.
first we have to apply a known voltage at the terminal of wire the we have to measure how much current flow in the wire then through R=V/I we can measure the resistance of the wire..
A single phase induction motor has two sets of coils and a centrifugal start switch. The start winding is in series with the start switch. The start winding provides a rotating magnetic field in one direction enabling the motor to start. The motor can be reversed by reversing the connections of either the start winding or the run winding but not both.
synchronous speed
stator,roto
Standard induction motor has a closed squirrel cage rotor, where as open ended induction motor has split phase rotor.
Resistance start-induction run motors are commonly known as split phase. They are only single phase motors. They have 2 sets of windings, the Start winding which is high resistance and low inductance made for thin wire, and the Run winding which is low resistance and high inductance made for thick wire. The 2 windings are set skewed about 30 degrees on a twist. This is to create the angular rotary motion, which is what a motor is all about. On start up both start and run windings are energised. Some form of switch disconnects the start winding when the motor is about 75% up to speed, and only the run winding remains in the circuit. There you have it.....
Yes, the induction motor has a rotor winding. It is usually one turn, shorted. This is how the magnetic fields generated in the stator induce a current in the rotor, which subsequently generates a torque from the opposing magnetic fields, stator to rotor.
Only Stator winding is similar in both the cases.
Like transformer induction motor has stator winding(Primary winding) and rotor winding(Secondary winding) separated by an airgap.Rotor winding(generally Al bars) are short circuited at the end to produce torque for the rotation.Hence the name short circuited transformer.
AC motor has two main winding components - stator and a rotor. Stator winding is stationary where as rotor winding is on rotating part.
This is how an induction motor normally works, hence the name. The supply voltage is connected to the stator winding(s) and a current is induced in the rotor. A synchronous motor, on the other hand, will have current supplied to the rotor through slip rings and brushes. The rotor current is generally supplied as DC though, or else rectified in the rotor.
An induction motor consists of a rotor winding and stator winding. Rotor windings are short circuited and stator winding are given electrical AC supply .Now lets do the physics behind it . As the current starts to flow in the stator winding , magnetic flux start to produce around it . due to it's alternating nature that flux varies and according to farady law emf is induced in the rotor winding .Since the rotor winding is short circuited the current circulates in it .And when a current carrying conductor is placed in magnetic field it experiances a force and hence if start to rotate.
The resistance of a motor winding is expressed in
Normally the machine is supplied from one side of the stator winding only and the other side is isolated connected in star or delta. Open-end winding means the neutral point of the machine is opened and now the supply is possible from both side of the stator winding of the machine.
The synchronous motor is made self starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate, therefore, in the beginning synchronous motor provided with damper winding starts as a squirrel cage induction motor. The exciter moves along the rotor. When the motor attains about 95%of synchronous speed, the rotor winding is connected to exciter terminals and the rotor is magnetically locked by the rotating field of the stator and the motor runs as a synchronous motor. While starting a synchronous motor, the field winding must be shorted through a suitable resistance so that the induced voltage is distributed throughout the whole winding and no part is subjected to the high voltage induced in the entire winding.
Single phase motor will not start automatically unless it has a start and run winding.
Both have 3 a phase stator winding, the squirrel cage has a rotor with bars arranged around it's periphery, these bars are joined at both ends by a continuous ring. This forms a closed circuit of low resistance which is fixed. The wound rotor (slip ring motor) is similar in construction but the bars are replaced by copper windings, similar to those in the stator. They are star connected and the three ends are brought out to slip rings which allow an electrical connection to be made to the outside world. When no connection is made between these ends and the stator is energised, little current flows in the stator which does not turn, but when some resistance is inserted, current flows in the stator windings and the rotor rotates. As the rotor gains speed the resistance is taken out of circuit and the slip rings shorted together. The motor runs as a cage induction motor.
Although the term 'conduction motor' isn't widely used, it refers to a motor whose rotor winding, as well as its stator windings, is supplied with an electric current. In the case of an 'induction motor', however, the current flowing through the rotor is produced by voltages 'induced' into the rotor windings by a rotating magnetic field created by the stator windings.