Get Your Motor Running

Motor manufacturers continue to innovate, keeping up with new challenges in motion control.

Motors have been around for a long time. The ones most people are used to seeing are probably the typical fat cylindrical AC synchronous motors that do a lot of industry’s heavy lifting.

But as anybody who designs motion control systems knows, the range and scope of motor offerings is impressive. The basic servomotor system and stepper motor have been around for many years and are the go-to motors for most motion control systems. However, motor manufacturers continue to innovate as their customers demand ever-more creative solutions for their design challenges.

Here’s an overview of some of the unique, innovative, and quirky motors for motion control that recently caught our eye.

Many a manufacturer has designed a custom motor for a specific customer need only to have that custom design become part of their standard offering. While this isn’t a new development, a few recent examples have produced some truly unique motor designs.

Wittenstein-wing-motor
Wittenstein’s wing motor features an innovative motor mounting system.

For starters, there is the James Bond-ish swing motor design from Wittenstein. This swing servo motor, also known as the wing motor because of its appearance, is the newest innovative mounting concept in motor mounting, originally created as a customized solution. The motor operates in the same way as a classic, one-piece direct drive motor.

The hollow-shaft direct drive wing motor has two swinging stator halves that feature a unique mounting concept for integration and operating scenarios where axial installation and removal in or from a machine aren’t possible. The split stator contains two parallel, three-phase systems that allow for the stator to be joined together in a controlled way. Each stator half contains a water-cooling pipe system made from stainless steel, preventing damage to the drive due to intense heat stemming from the roll. It can be easily retrofitted or dismantled for maintenance, and is designed to withstand the harshest of operating environments.

Direct-drive motors continue to be in demand in more applications. A direct-drive motor can eliminate many of the mechanical drive components, which add compliance to a system, such as belts and chains and ball or lead scews. By attaching directly to the load, there are a number of advantages in terms of performance, reliability, and precision.

Some companies, such as Loomis, Cal. based Applimotion, are small companies that do almost exclusively custom design work. Best known for their pancake-style flat motors used where direct-drive is required, the company has recently begun offering custom design engineering to incorporate its frameless motor kits into application specific direct-drive motors.

The company focuses on creating designs with special mechanical requirements, high accuracy for precision positioning, or harsh environments. The process is straightforward. A motor kit is selected based on performance needs after which engineers guide you through the selection of feedback and precision mechanical attributes. Finally, a complete custom direct-drive motor is fabricated and delivered, including unique testing if required.

Applimotion-flat-pancake-motor
Custom designed motors are the focus of much of Applimotion’s work. Flat pancake motors are used in a range of direct-drive applications.

Applimotion has supplied their motors to a wide range of industries including energy, medical, unmanned-vehicles, inspection, metrology and military/defense. When standard off-the-shelf solutions currently available don’t have the right features or are too expensive, the company can work with customers to create an affordable direct drive device that fits the application.

Another innovative design comes from UK-based SEM. A new line of liquid-cooled servomotors was introduced at last year’s SPS/IPC/Drives show in Germany. Their new HW series liquid-cooled servomotors can deliver over twice the power of standard servomotors.

Again, many of the design improvements came from issues being raised by customers. Specifically, motors used in precision machine tool applications, where tolerances may be in the micron range, need to minimize temperature fluctuations during machine operation. Limiting the heat generated by the motor helps to maintain a steady ambient temperature and minimize any undesired heat effects.

Liquid-cooled-servomotors-from-SEM
Liquid-cooled servomotors from UK-based SEM feature increased power density compared to standard air-cooled servomotors.

Customers can also select various feedback devices, including precision encoders and resolvers. The motor’s dynamic performance makes it ideally suited for use in high-speed positioning and packaging systems, punch presses and servo pump drives.

Another ongoing trend is the integration of motors with other control features. This motor subcategory is often called an integrated motor or integrated servomotor. The design combines a motor with other components such as a feedback device, an amplifier or motor drive, a communication port and a motion controller.

For well over a decade, since the mid 1990s when introducing the first integrated servomotor to the market, Animatics has been an innovator in the integrated servomotor market. Last year, it introduced a SmartMotor with 900W of peak power. The OEM Series SmartMotor is a complete, programmable, motion control system that’s compact, user friendly, and cost-effective. Using a patented design, SmartMotors incorporate a servomotor, amplifier, encoder and motion controller into the same integral frame.

Animatics-SmartMotor
Animatics’ SmartMotors integrate a motor with controller, drive, and communications capability.

Other motor manufacturers are also offering integrated motors, which are finding use in a range of applications. And one of the hottest areas these days is in the alternative energy field, specifically wind and solar energy.

To that end, a new line of integrated servomotors from Dunkermotor is geared specifically for solar power applications. The company’s brushless dc Solar Tracker Motors (STM) with integral fieldbus-enabled motion controllers are said to reduce development time, lower installation costs, and provide lowest total cost of ownership (TCO) in a variety of solar tracking applications. It’s said that electric energy production can be increased by up to 35% with solar tracking compared to fixed photovoltaic panel systems.

Solar-Tracking-Motors-from-Dunkermotor
Solar Tracking Motors from Dunkermotor feature integrated fieldbus-enabled controllers along with a special solar tracking function block.

The new STM line enables the control of up to 127 motors over a 5,000 m (16,400 ft) bus length using the motors’ integral CANopen interface with a single off-the-shelf PLC having a solar tracking function block. The STM integral control brushless motors can also be used with industrial PCs as well as Profibus and Modbus networks.

The embedded intelligence of the motor’s integral controls reduces bus traffic by running complex routines onboard, such as homing and closing the position loop with an attached absolute encoder or inclinometer. In addition, the motor’s embedded intelligence can also take over mission critical functions, like returning to a safe position, when the network is down.

Another development is the blurring of the lines, both in terms of functions and cost, between the two most common motor technologies used in motion control applications, namely servomotors and stepper motors.

The Junma AC Servo from Yaskawa is designed for plug-and-play use.

Case in point; the new line of Junma AC servomotors from Yaskawa is said to offer an alternative to stepper technology at a similar price point. The Junma AC Servo features a plug-and-play design that doesn’t require gain adjustments or parameter settings.

Junma is said to eliminate time-consuming setup while accepting pulse reference input from a PLC or host controller. After connection, users can then choose the reference pulse switch settings on the amplifier that match the controller’s reference output.

With system parameters set on power up, Junma’s machine load inertia is automatically calculated, while its tuning gains are dynamically adjusted, even during load changes, enabling the system to adjust to varying conditions.

Advanced control functions such as vibration suppression and adaptive tuning simplify the commissioning of the machine while maintaining optimum efficiency and high-precision positioning. Junma also features other functions such as homing to marker pulse, jogging, torque limiting and electronic gearing.

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