CHARACTERISTICS OF DC MOTORS BASICS AND TUTORIALS

Characteristics of DC motors
• DC motors have good starting torque as well as good speed-regulation capabilities.

• Permanent magnet-type DC motors are used for exact positioning of objects with high-operating torques.

• Series type gives high-starting torque; hence the ability to start with high loads.

• Series motors when operated with no loads can attain high speeds causing harm to motor.

• Shunt-type motors have good speed regulation.

• Direction reversal of DC motor can be done by changing the leads of the armature or the field.

• Speed of DC motor changes either by changing armature voltage or field current.

• If armature voltage is increased, speed increases till base speed and vice versa.

• Similarly, speed can be increased above base speed, by decreasing field current.

• In shunt motors torque is proportional to armature current.

• In series motors torque is proportional to square of armature current.