The motor and drive combination is a basic building block of motion control. Each component is useless without the other. So it’s pretty important to come up with a good definition for what the “system” performance needs are to make sure that you end up where you need to be in your design.
Generally, we go to single source suppliers whose motors and controls are designed to operate together. This approach guarantees minimum performance levels which the supplier can be held accountable for, and that’s a great thing. But it usually comes with a huge list of features that will not be used in the application, but which you must pay for anyway.
In the industrial user community this is a great benefit because common environmental conditions such as dust, dirt, oil, or washdown conditions are more difficult to deal with and many products are built to these environmental standatds. No special precautions are needed to make the equipment work. And the suppliers warranty their equipment for continuous operation at stated speed, torque and environmental conditions.
But as we migrate into other businesses, machinery builders and equipment manufacturers have to apply the same motors and controls in larger numbers, and the overhead costs of motors and controls designed for industrial use become very expensive and make the cost of machinery less competitive.
In the machinery world, much of the electrical components will be built into control cabinets. So if the packaging is going to be provided, is an enclosed controller somewhat redundant? Or can the motor speed control be integrated into the motor physically to reduce cost? This is especially attractive if the cost of cabling a single motor can run 10-20% of the total cost of the motor and control.
There are performance elements that need to be considered in the applications as well. How should the motor behave at zero speed? What kind of torque regulation is needed? What is the exact duty cycle of the application (on time versus off time)? In these areas of motor and control operation the relationship of the motor to the drive is critical. The drive electronics must have the ability to regulate current going through the motor without casusing overheating. Some type of sensor on the motor must provide information about the position of the rotor at fairly high resolution, certainly more than every 120 degrees of rotation as with the common Hall effect sensors.
So as much as we may look at the purchase of a motor and controller as a system, there are a lot of nuances involved in the search process for the right hardware for any given application. And that is probably one of the more difficult parts of doing motion control applications.