# Some parameters of DC motor you should know

As the executive component of the motor, the DC motor has a closed main magnetic circuit inside. The main magnetic flux flows in the magnetic circuit while interlinking with the second circuit. One magnetic circuit is used to generate magnetic flux, called the excitation circuit, and the other is used to transmit power, called the power loop or armature loop. The Current DC motors are all rotating armature type, that is to say, the magnetic pole stator composed of the exciting winding and the iron core surrounded by it, the armature winding with the commutation unit and the armature iron core are combined to form the rotor of the DC motor.

1. Torque: the Torque at which the motor can rotate, in kg.m or N.m

2. Torque coefficient: the proportional coefficient of the Torque produced by the motor, which generally represents the magnitude of the Torque produced by the armature Current per ampere;

3. Friction Torque: Torque loss caused by friction in brushes, bearings, commutation units, etc.;

4. Starting Torque: the rotation Torque generated by the motor starting;

5. Rotation Speed: the Speed at which the motor rotates. The engineering unit is r/min, which means revolution per minute. In the international system of units, it is rad/s, which means arc per second;

6. Armature resistance: The internal resistance of the armature, in a brushed motor, generally includes the contact resistance between the brush and the commutator. Since the resistance will generate heat when Current flows, it is always hoped that the armature resistance should be as small as possible;

7. Armature inductance: Because the armature winding is composed of metal coils, there must be inductance. From the perspective of improving the performance of the motor, the smaller the armature inductance, the better;

8. Electrical time constant: The time it takes for the armature Current to reach 63.2% of the stable value from zero. When measuring the electric time constant, the motor should be in the state of blocking and applying the driving Voltage with step property. In electrical time constant engineering, resistance R A and inductance L A of armature winding are often used to find out:

T e = L a/ R a

9. Mechanical time constant: the time taken for the motor to reach 63.2% of No Load Speed at the beginning. When measuring the mechanical time constant, the electric motor should be in a No Load running state, and a step motor should be applied.

We believe that these parameters help you in choosing which motor is more convenient and efficient. Kinmore Motor provides you with the best driving scheme and customized services.