Large Motor starting 102: Motor applications and their characteristics – for a better motor management
Let’s continue with our motor management topic, part 2. In my previous blog post , the electrical, thermal, and mechanical constraints necessary to consider for large motor starting have been presented in detail. We will focus now on the main motor application characteristics impacting the selection of motor starting methods. So, what are the motor application characteristics to consider before selecting the starting method? There are two main types: mechanical and operating characteristics. Application torque and inertia are the main mechanical characteristics. The above figure shows various forms of load torque evolution with speed. By far, quadratic torque applications are the most frequent in number and suitable for all the starting methods — direct on line, progressive start, and variable speed drive. Applications with that kind of torque include pumps, fans, compressors, and practically more than 70% of applications. The other torque shapes are seen in electro-intensive seg...