How do you increase armature speed?

How do you increase armature speed?

The flux can be changed by changing the current with a shunt field rheostat. Resistance of the armature circuit – By decreasing the resistance, there is increase in the armature current which causes a larger torque to be developed. This increased torque causes the dc motor to increase in speed.

What happens to motor speed when armature resistance is increased?

By varying the armature circuit resistance, the current and flux both are affected. The speed–current characteristic of a series motor is shown in the figure below. When the value of variable resistance Re is increased, the motor runs at a lower speed.

How can the effect of armature reaction be reduced?

1) The armature reaction causes the distortion in main field flux. This can be reduced if the reluctance of the path of the cross-magnetizing field is increased. The armature teeth and air gap at pole tips offer reluctance to armature flux. Thus by increasing length of air gap, the armature reaction effect is reduced.

How do you find current in armature?

How to Calculate Armature Current? Armature Current calculator uses armature_current = Field Current+Load current to calculate the Armature Current, Armature Current is the Current which Flows in Armature Winding or rotating Winding of Motor or generator.

How can we increase the speed of a DC motor?

Input Voltage: For a fixed load, the speed of the motor is affected by the applied voltage. Increase in voltage = increase in speed. Load Torque: For a fixed voltage, the speed of the motor is inversely affected by the load. Increase in load torque = decrease in speed.

What is the purpose of armature resistance?

Armature Winding resistance is the ohmic resistance of the copper winding wires. A brush is used to provide electrical contact between the stationary contacts and moving parts like commutator or slip rings.

What are the main effects of armature reaction?

The adverse effects of armature reaction: Armature reaction weakens the main flux. In case of a dc generator, weakening of the main flux reduces the generated voltage. Armature reaction distorts the main flux, hence the position of M.N.A. gets shifted (M.N.A. is perpendicular to the flux lines of main field flux).

What is armature reaction and its effect?

Armature reaction is the effect on the main field flux of that flux set up by the currents in the armature winding. The effect is the same for both lap- and wave-wound machines.

What is the formula for current taken by dc shunt motor armature?

Since you know the power rating of the motor and the supply voltage, you can calculate the current required by the motor from the equation; P=VxI .

How to reduce distorting effect of armature reaction?

Thus by increasing length of air gap, the armature reaction effect is reduced. 2) If reluctance at pole tips is increased it will reduce distorting effect of armature reaction. By using special construction in which leading and trialing pole tip portions of laminations are alternately eliminated.

Is it possible for an armature to be damaged?

And we never want to have continuity between any of the bars and ground. It’s always supposed to be open circuit. If your measurements fail any of these, it’s very possible the armature has broken or damaged windings and will not function properly.

How does a compensating winding reduce the armature reaction?

The compensating winding are basically used to neutralize the armature flux in the pole arc region which will otherwise cause sever distortion of main field flux. By using high reluctance pole tips, reduction in armature flux and using strong main field flux poles we neutralize the armature reaction.

How are the bars connected to the armature?

On this armature, we have a shaft and a commutator, which has bars. The commutator bars are connected to the armature winding and the winding is wound around the teeth on the lamination stack. This creates an electromagnetic effect, which interacts with the permanent magnets in the motor housing, causing the motor to turn.