A newer subcategory of servomotor is often called the integrated servomotor. In this type of design, the motor itself is combined with the other essential components of a complete motion control system including the feedback device (generally an encoder), the amplifier or motor drive, a communication port and the motion controller itself.
Such systems are said to offer greater reliability mainly because there are fewer parts to connect together. Also, fewer external connections means less cabling and wiring. Less cabling and wiring reduces costs, as does the fact that the components that one would usually purchase separately such as the motion controller and the drive are integrated into one package.
These integrated servomotors are also designed to be programmed easily and quickly, which can help reduce development times. Communication options range from simple serial communication links such as RS232 or RS485 to more advanced network topologies suited to complex motion control tasks such as CANopen, DeviceNet, or Ethernet protocols.
As with any motor, when selecting an integrated servomotor for an application, the most important step is determining the characteristics of the load. This is why properly calculating the load torque is such an important part of selecting the right motor and designing it into the application. A good rule of thumb to keep in mind is to try and keep the actual operating conditions below the published limits of the motor in order to ensure reliable and long-life operation.
Motor sizing parameters are usually based on the torque curve and moment of inertia of the load. These two factors can help determine the motor’s operating bandwidth. Sets of torque curves depict limits of both continuous and peak torque for the given motor over their full range speed.
There are different types of torque curves, dealing with peak torque and continuous torque as well. Peak torque curves can be derived from dyno testing and represent the point at which peak current limit hardware settings of the drive prevent further torque in an effort to protect drive stage components.
For any mechanical system, if the motor is operating in its optimum range, then the system will be performing at its best. Beyond the motor itself, depending on the specifics of the application it may be necessary to adjust mechanical components such as gear reducers, belts, lead screw pitch or pinion gears in order to achieve optimal system performance.
Content provided by Design World.