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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.
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∙ 13y ago
Wiki User
∙ 10y agomotor whose speed can be controlled is called a variable-speed motor; dc motors are variable-speed motors. The speed of a dc motor is changed by changing the current in the field or by changing the current in the armature. When the field current is decreased, the field flux is reduced, and the counter emf decreases. This permits more armature current. Therefore, the motor speeds up.
When the field current is increased, the field flux is increased. More counter emf is developed, which opposes the armature current. The armature current then decreases, and the motor slows down. When the voltage applied to the armature is decreased, the armature current is decreased, and the motor again slows down. When the armature voltage and current are both increased, the motor speeds up.
In a shunt motor, speed is usually controlled by a rheostat connected in series with the field windings, as shown in figure 2-8. When the resistance of the rheostat is increased, the current through the field winding is decreased. The decreased flux momentarily decreases the counter emf. The motor then speeds up, and the increase in counter emf keeps the armature current the same. In a similar manner, a decrease in rheostat resistance increases the current flow through the field windings and causes the motor to slow down..
Shoaib Khan musazai
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What is constant speed DC motor?
Dc shunt motor is constant speed motor.Its speed is constant with armature current.This shunt motor is used in paper mills and drilling machines
What are industrial applications of DC shunt motors?
Dc shunt motor is a constant flux and constant speed motor . So that it is used in centrifugal pumps ,machine tools ,blowers and fans etc.
Would it be correct to say with a fixed field voltagethe speed of a shunt motor is proportional to its armature voltage?
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 is the effect of increasing number of poles on the speed of an induction motor?
As the number of poles (P) increases, the speed of an induction motor (N) decreases. As seen by the formula: N=(120*f)/P
Why induction motor current increase when load increase?
The slip is proportional to the load torque in an induction motor. This can also be seen as a reduction in speed causing extra current to be induced in the rotor to supply the increased torque.
Which DC motor is constant speed motor?
Dc shunt motor is constant speed motor.Its speed is constant with armature current.This shunt motor is used in paper mills and drilling machines
Why is motor current draw lower at full speed?
Because full speed is unloaded. As you load the motor, speed decreases, and slip increases, with an accompanying increase in current.
As a motor armature turns faster and faster net current in the motor windings decreases or increases or remains unchanged?
as a motor armature speed increases,the net current in the motor windings decreases due to MAGNETIC DRAG. which is a common phenomenon in the ac machines.
What is constant speed DC motor?
Dc shunt motor is constant speed motor.Its speed is constant with armature current.This shunt motor is used in paper mills and drilling machines
What increases when a wave period decreases.?
When a wave period decreases, speed increases.
How does speed affect Power?
Speed is directly related to power. As speed increases, power also increases. And as speed decreases, power also decreases.
Why speed control of DC shunt motor is necessary?
The total voltage of the batteries or DC power source connected to a shunt motor affects how first it moves. Increasing the DC voltage will make the shunt motor run faster.
What are industrial applications of DC shunt motors?
Dc shunt motor is a constant flux and constant speed motor . So that it is used in centrifugal pumps ,machine tools ,blowers and fans etc.
Why do you control the speed of constant speed dc shunt motor?
no it controls your anus
Would it be correct to say with a fixed field voltagethe speed of a shunt motor is proportional to its armature voltage?
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 is the effect of increasing number of poles on the speed of an induction motor?
As the number of poles (P) increases, the speed of an induction motor (N) decreases. As seen by the formula: N=(120*f)/P
What is DC shunt motor?
A shunt DC motor connects the armature and field windings in parallel or shunt with a common D.C. power source. This type of motor has good speed regulation even as the load varies, but does not have the starting torque of a series DC motor
