Bringing Liquid Cooling to Servomotors: Beckhoff AM8300

To increase the efficiency and boost the standstill torque and high speed demands, Beckhoff Automation recently announced the newest member of the servomotor catalog, the water-cooled AM8300, founded on the reliable technology behind its predecessor, the AM8000 servo series.

Heat in Motor Drive Systems

Every rotating component, whether powered by electricity, fluid, or a mechanical device, inevitably builds up heat. For electrical drive systems, some of the most extreme heat comes from standstill power: the motor is consuming electricity, but cooling fans are not operating. When energy is consumed, it’s converted into some other form; if the motor stands still, more energy is turned to heat.

High speeds can also pose heating challenges. The power demands continue climbing, but the convective cooling cannot keep up with the increasing thermal output.

Beckhoff’s new servo motor with integrated water cooling. Image used courtesy of Beckhoff

To combat the heating problems in electronics, liquid cooling systems have long been used inside computer cases for performance processors, removing the heat with a liquid medium, usually water, with far more conductive efficiency than stagnant or moving air.

Because of this liquid cooling system, the new AM8300 servo motors from Beckhoff can withstand a higher sustained operating speed, as well as far higher (up to 3x higher) standstill torque ratings.

Beckhoff’s AM8300 Servomotor

The servo series has numerous flange and length offerings, along with a wide range of standstill torque ratings. The various flange sizes present a mounting face with a bolt diameter of 72 mm (F3) up to 194 mm (F7).

Scaled images of the smallest AM8300 motor frame (F3, on the left) compared to the largest frame (F7, on the right). Image used courtesy of Beckhoff

Holding Torque

The standstill, or holding torque for this motor series varies between 5.00 N-m for the smallest motors and boasts up to 358.5 N-m for the largest. The consumed current for these torque ratings can be up to 125 amps for some models.

Max Speed

The higher sustained operating speed is evident in these motors, with the smaller products capable of reaching a max speed of 8000 rpm, down to 2500 rpm for large motors. These servo applications excel compared to a typical inverter-driven synchronous motor, which usually does not exceed 2000 rpm under any operating scenario.

Optional Features

The AM8300 water-cooled motors have several options, including a backlash-free permanent magnet (PM) holding brake, which increases the deceleration rate under high-load conditions. An optional shaft seal and keyway offer flexibility for various fixtures mounted to the motor shaft.

Water-Cooling Challenges

As expected, mixing liquids and electrical systems should only be done under the right circumstances. The fittings on the AM8300 motor series provide a watertight connection, and the manufacturer will specify the proper types of water quality, hose materials, and pump flow rate to maintain safe and reliable operation. Adding liquid cooling does provide major advantages, but the new fluid system must be installed and operated with care.

Motion: Precision, Speed, and Efficiency

Every motion control system is designed with a few aspects in mind. Namely precision is the number one factor in determining the success of a system. In some cases, high speed is a necessity. Finally, in all cases, reducing waste energy is critical for lowering costs and meeting sustainability goals.

The new liquid-cooled AM8300 servo motors from Beckhoff provide advancements in all three aspects, with higher sustained speed, increased holding torque, and reduced waste energy. Cool, right?