Commissioning of DC Motors
Introduction
Direct current (DC) motors exist in thousands of applications in the modern world. Their considerable versatility and low cost has made them the ubiquitous motion actuation technology. Examples of DC motor applications include machine tools, toys, robotics, and aerospace applications. Their potential complexity and stringent reliability requirements necessitate a methodical approach to commissioning and testing. This paper will provide an overview of the commissioning of DC motors, and focus on best practice methods for testing.
Configuring DC Motors
DC motors are composed of two main components: the stator and the rotor. The stator includes the components of the motor which remain stationary, while the rotor are the components which rotate. Both of these components should be configured correctly to ensure optimal performance.
Stator: The stator generally consists of windings, magnets, and a timing belt to produce torque. Windings should be connected correctly and in phase with each other to ensure that the stator produces a magnetic field. If the winding connections are made incorrectly, the field strength may be too low and the desired torque will not be produced. The magnets should then be inserted into the stator frame and the timing belt adjusted to the correct tension.
Rotor: The rotor will usually consist of a set of commutator segments and brushes. Each brush should be securely mounted and adjusted for optimal contact with the commutator. If the brushes are loose, the rotor can vibrate and make contact with the brushes intermittently. This can lead to arcing or reduced performance. Additionally, the commutator should be inspected for any surface irregularities which can decrease performance.
Test Setup
The appropriate voltage supply should be attached to the DC motor and any other components that are necessary should be in place (e.g. drive shaft, encoder, etc.). The voltage should then be adjusted to simulate the expected operating voltage of the motor. Generally, this will be a voltage which is slightly less than the rated voltage to ensure safety. If a speed controller is being used, it should be configured to the appropriate settings such as maximum speed, acceleration rate, and current limit.
Testing
It is important to ensure that the DC motor is functioning properly before use in a real-world application. The following tests can be used to ensure the motor is able to generate the desired performance.
First, the motor should be tested without any load to ensure it is working properly. The rotor should spin freely and any vibration or excessive noise should be noted. Any problems should be addressed before further testing is done.
Next, the motor should be tested under different load conditions. Each load condition should be tested separately to ensure optimal performance. The motor should also be tested for any issues at different speeds and acceleration rates when applicable. All failures should be recorded and addressed.
Finally, the motor should be tested for endurance. This should involve running the motor for an extended period of time at different operating conditions. All failures should be recorded and the average performance should be available.
Conclusion
Direct current motors are used around the world in various applications, each requiring different performance characteristics. To ensure that the motor can perform as expected, it must be commissioned and tested properly. This includes ensuring accurate configuration of the stator and rotor components, as well as testing under a variety of conditions. By following the steps outlined in this paper, users can ensure their DC motors are performing properly.
