The performance of a d.c. motor can be judged from its characteristic curves known as motor characteristics, following are the three important characteristics of a d.c. motor:
(i) Torque and Armature current characteristic (Ta/Ia) It is the curve between armature torque Ta and armature current Ia of a d.c. motor. It is also known as electrical characteristic of the motor.
(ii) Speed and armature current characteristic (N/ia) It is the curve between speed N and armature current Ia of a d.c. motor. It is very important characteristic as it is often the deciding factor in the selection of the motor for a particular application.
(iii) Speed and torque characteristic (N/Ta) It is the curve between speed N and armature torque Ta of a d.c. motor. It is also known as mechanical characteristic.
(i) Torque and Armature current characteristic (Ta/Ia) It is the curve between armature torque Ta and armature current Ia of a d.c. motor. It is also known as electrical characteristic of the motor.
(ii) Speed and armature current characteristic (N/ia) It is the curve between speed N and armature current Ia of a d.c. motor. It is very important characteristic as it is often the deciding factor in the selection of the motor for a particular application.
(iii) Speed and torque characteristic (N/Ta) It is the curve between speed N and armature torque Ta of a d.c. motor. It is also known as mechanical characteristic.
