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How will the armature current and the output power of a dc shunt motors change with increasing load?
With increasing torque load the armature tends to slow down; the motor draws more current to compensate, and if there is armature resistance the back emf generated by the armature falls to allow the increased current to flow, which causes the motor to settle at a lower speed.
The mechanical output power is the speed times the torque, and increasing the torque increases the power output provided the speed does not drop much.
What else can I help you with?
What does a armature or rotor do?
The Armature(or rotor) is a electromagnet inside a motor and alters the magnetic field inside the motor when it rotates. In DC motors it is connected to a Commutator. In AC induction motors the armature isn't connected to a power source.
What is armature in motors?
The armature has the stationary (not physically moving) magnetic field, which attracts the magnetic field in the rotor. Since DC does not alternate, a split ring is used to alternate the current (and resulting magnetic field), so that the rotor will spin.
How armature resistance can be determined in a synchronous generator?
synchronous impedance can be calculated by performing oc test and sc test. by oc test,since the armature current is zero Vt=Ef . in short circuit test ,entire emf is consumed in circulating the short circuit current Isc,through the synchronous impedance. Zs=Ef/Isc.= (open ckt. terminal voltage for a certain field current)/(short ckt. current at the same field current)
What is the difference between a field winding and an armature winding in any machine?
In electrical machines such as motors and generators, the field winding is responsible for producing a magnetic field within the machine. This magnetic field interacts with the armature winding, which carries the electric current and generates mechanical power. The field winding typically has fewer turns of thicker wire compared to the armature winding, which has more turns of thinner wire to handle higher currents.
Why a DC series motor should never be stared without load?
since torque is proportional to flux and armature current . Flux for dc shunt is constant . torque is proportional to armature current only. And initially armature current is very low hence it cannot be started at load .
Why the armature voltage E changes when the field rheostat is varied in shunt motors?
In shunt motors, the armature voltage ( E ) changes when the field rheostat is varied because altering the resistance in the field circuit affects the field current and, consequently, the magnetic flux produced by the field winding. When the field rheostat is decreased, the field current increases, leading to a stronger magnetic field and a higher back electromotive force (EMF) generated in the armature. This results in a change in the armature voltage, as the increased back EMF reduces the net voltage across the armature. Conversely, increasing the field resistance weakens the magnetic field, reducing back EMF and allowing the armature voltage to rise.
What is armature or rotor?
An armature, often referred to as a rotor in the context of electric motors and generators, is the rotating component that generates electromagnetic force. In electric machines, the armature typically consists of coils of wire wound around a core, which produces electricity when it moves through a magnetic field. In motors, the armature receives electrical current, creating a magnetic field that interacts with the stator to produce motion. The design and function of the armature are crucial for the efficiency and performance of the machine.
What does a armature or rotor do?
The Armature(or rotor) is a electromagnet inside a motor and alters the magnetic field inside the motor when it rotates. In DC motors it is connected to a Commutator. In AC induction motors the armature isn't connected to a power source.
How speed increases when flux decreases in dc shunt motor?
Increasing flux, torque of the dc motor will be increased and speed of the dc motor will be decreased as speed of the dc motor is inversely proportional to that of the flux and the torque of the dc motor is directly proportional to the flux.
What is armature in motors?
The armature has the stationary (not physically moving) magnetic field, which attracts the magnetic field in the rotor. Since DC does not alternate, a split ring is used to alternate the current (and resulting magnetic field), so that the rotor will spin.
Why armature resistance is maximun in motors?
avoid high stating currents
What is the electrical term excitation mean?
Excitation is normally used to describe the current supplied to the field winding of a motor. A motor has a rotating armature with a coil that rotates in the magnetic field produced by a fixed field coil. The current in the field coil can be taken from a series or parallel connection to the armature coil, or (usually for larger motors) it can be supplied independently via some sort of controller. Excitation can be used to control the speed of DC motors or the power factor of synchronous motors.
What purpose does a capacitor serve in a single phase motor?
These are actually single-phase induction motors. There is no electrical connection to the armature itself. To make the armature turn within the windings an electric current has to be induced in the it, and this is done by making the magnetic field move in relation to the armature. (The same principle is involved as moving a magnet over a wire to get an electric current.) With an electric current flowing in the armature there is a magnetic field set up around it which pushes against the magnetic field in the windings to make the armature turn.OK, but how to make the magnetic field move? That's the purpose of the capacitor.Capacitors have the property of advancing alternating current by (if I remember correctly) 90 degrees. In the simplest case, there are two windings in one of these motors. Unaltered electric current is sent through one of the windings. Some electric current is sent through the other winding and a capacitor. Now, because the two windings are being energised by currents that are out of phase by 90 degrees it is as if the magnetic field is moving. The armature responds by moving.
How do you spell amiture?
The correct spelling is armature (wound coil in motors and generators).
How armature resistance can be determined in a synchronous generator?
synchronous impedance can be calculated by performing oc test and sc test. by oc test,since the armature current is zero Vt=Ef . in short circuit test ,entire emf is consumed in circulating the short circuit current Isc,through the synchronous impedance. Zs=Ef/Isc.= (open ckt. terminal voltage for a certain field current)/(short ckt. current at the same field current)
What are the comparisons between motors and generators?
Electric Motors • The electric motor converts electrical energy into mechanical energy • The shaft of a motor is driven by the magnetic forces developed between the armature and field • Current has to be supplied to the armature winding. • Motors obey Fleming`s Left Hand Rule • Electric Motors Fleming`s Left Hand Rule The Left Hand Rule shows what happens when charged particles enter a magnetic field. Generators • A generator converts mechanical energy into electrical energy. • A shaft attached to the rotor is driven by a mechanical force • Electric current is produced in the armature windings. • Generators obey Fleming's Right Hand Rule • Generators The Right Hand Rule shows how a current-carrying wire generates a magnetic field.
What are the three quantities that may be considered as parameters in order to change the speed of a dc motors?
Input voltage Load Number of windings and arms
