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What happen if we do the 3 phase winding in rotor of induction motor and give the 3 phase supply only stator winding?
Wiki User
∙ 11y ago
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.
Wiki User
∙ 11y ago
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How does an induction motor start?
The emf induced in the rotor depends upon the rotor frequency which further depends on relative speed between rotor and synchronous speed of rotating magnetic field. The relative speed at the time of starting or standstill is maximum and hence large emf in induced in rotor conductors or winding due to which very high current flows in rotor which is generally 5 to 7 times of the full load or running current of an indication motor. The starting current, sometimes called inrush current will be 8-10 times higher than the motor's rated current because the motor is at rest. When at rest, the motor appears to be a transformer, with it's secondary winding short circuited, i.e. the rotor winding or squirrel cage is a closed circuit. This results in a low impedance to the system voltage and the motor has a "locked rotor" current of typically 6 times full load current, but also up to 8 and sometimes 10 times current. This starting value is independent of any load attached, however, the inertia of the motor and load has to be overcome. This is especially true when the motor is connected to a load, like a conveyor belt with product on it. The larger the inertia, the longer the motor takes to reach full speed. As the motor accelerates, part of the starting current power overcomes this inertia and is conveted to kinetic energy. The remaining power of the starting current heats the rotor, up to possibly 250 deg C for a "long" start (20 seconds!!). During the first couple of cycles of AC current, transient currents make some of the phases have higher assymetrical values, which can cause nuisance tripping of the supply breakers to the motor, when protection settings are too low! Equation for current: I = P / cos phi / ( 1.732 * V), (cos phi can be 0.3 during starting). V (voltage) stays pretty much constant, therefore I (current) must rise (but is limited to the locked rotor value for the specific motor) as P (power) is required to start the motor and to keep it running. Some voltage drop will occur for most power systems during a motor start, thus with a constant locked rotor impedance, the starting current will reduce proportionally. I start = V / 1.732 / Z (locked rotor) for a three phase motor. (Z is fixed) When nearly full running speed is reached, the current drops rapidly to full load current or less, depending on the actual load attached. -Don't forget to recommend Kevlarster if you like this answer!
If a cell did not have a supply of amino acids what could happen?
No proteins.
What are the causes for unbalance of currents of a 3 phase a c motor?
unbalance voltage supply resistance between phase unbalance joints of coil loose winding short with body
How does the induction motor start?
It's self-started. and it has a normal speed less than that of synchronous. but its speed decreases as the load increases. An induction motor has 2 sets of coils in it that are physically displaced from each other. (One is the 'start' winding, connected only during starting, and a 'run' winding, connected whenever the motor is turned on.) The sets of coils have different electrical charactreristics, and when current flows in the coils, they each create their own magnetic fields that are displaced in time by the different values of coil resistance and inductance. The physical and timing displacements produce a combined magnetic field that rotates through the iron core and copper or aluminum bars of the rotor, inducing a current in the bars ('induction' motor....) creating a magnetic field around the bars that repels the original rotating field. This magnetic repulsion pushes the rotor around, driving the motor (and the load). The 'start winding' has a high resistance and gets VERY hot if left connected once the motor has started. It is usually turned off (by a centrifugal switch) once the motor is running, and the 'pulsating' field from the 'run' winding keeps the rotor turning. Some motors use a capacitor (or 'condenser') to enhance the displacement between the magnetic fields (and increase the force of repulsion) to improve starting torque, and a smaller capacitor to improve running torque and smoothness of operation. Small, low torque motors may not have a 'start' winding, but rather a single turn, short-circuited coil ('shading ring') on part of each of its poles to create a weakly rotating magnetic field - but without a switch or capacitor.
What will happen when the light in photosynthesis is over supply?
If the light is over, photosynthesis process will stop.
What will happen of you give AC supply to stator winding of DC generator?
why the supply is given to the stator of dc generator give answer
What is the meaning of open end winding induction motor?
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.
What is induction motor in physics?
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.
Why you have to connect DC supply to the induction motor?
To start an induction motor we have to excite field. The excitation is done by connecting the DC supply to the field winding's.
What are the differences between single phase induction motor and a stepper motor?
An induction motor is predominantly a AC device to convert electrical energy to mechanical. The operational windings are usually on the stator which is normally the outer frame of the motor. The rotor has laminated iron core drum with special windings which are in no way physically connected with the stator circuit. When the stator is energised with a suitable AC supply of a predetermined frequency range, a rotating magnetic field is generated. This in turn induces a voltage by transformer type action into the special winding on the rotor. The current flowing in the rotor windings tries to oppose any voltage induction from taking place in the rotor. This can ideally happen when the rotor is turning at exactly the same speed as the stator magnetic field. In practice the stator will keep running at a speed slightly slower depending on the rotor load. The stepper motor is more of a mechanical postioning device & the powers handled are far lower than of induction motors. It also is basically a DC pulse operated device. It has special pairs of windings on the stator which have to be energised in a particular sequence for correct operation. The rotor consists of a drum with very strong permanent magnets arranged in a pattern such that the pulsed energisation of the stator will cause the rotor to follow rotating pattern caused by the pulsed current. If the stator winding is energised with DC the stator will lock to the magnetic field & will not rotate for considerable torque on the stator. The stepper can rotate at wide rates from zero to a certain maximum depending on the motor & supply characteristics.
What is meant by induction machine?
An induction motor is so-called because the currents circulating in the machine's rotor are due to voltages induced into the rotor conductors through 'transformer action' from the field windings located on the stator. In other words, there is no external electrical supply to the rotor which, instead, behaves in a similar manner to the secondary winding of a transformer.
What happens if 3 phase supply is given to stator and rotor both in a induction motor?
its impossible to give suppy to rotor of an induction motor,because of it a closed path for circulating currents.
How can you reverse the direction of rotation in an induction motor?
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.
What are field windings and armature windings in a dc motor and generator?
generators have two types of winding , * at armature also called armature winding( winding around shaft , we can say), which is the moving part. note that armature also consists of magnets along with windings. hence produces field arount it. * and at stator also called field winding, because when armature rotates its flux(field) is cutted by the stator windings and produces mutually induced e.m.f in it( in stator windings off course) causing current to flow. this current also produces some electric field around it which is in return cutted by the armature windings hince a little amount of e.m.f ( also called back e.m.f) produced in armature due to stator winding current. know this current in armature (due to back e.m.f produced by stator winding) produces additional field , hence causing more current in stator winding. this is the reason that why stator windings are called field winding( as they cause electric field of armature stronger and cause more current in output). note that out put is taken from the stator windings in generators.
What will happen if inductor connected with DC supply?
i think in case of dc supply there will not be any induction
How is the synchronous motor made self starting?
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.
Why transformer supply is ac?
trf cannot work on dc. the primary flux must vary for induction to occur in the secondary winding. howlunf
