Why Choose a Complete Brushless Servo System?
A brushless servo motor generates torque, but the overall performance of a motion axis also depends on the servo drive, which controls the current, velocity and position loops. Performance also depends on the encoder, which measures motion, and the PLC or motion controller that coordinates the machine.
With a complete system from the same manufacturer, cables, parameters and commissioning procedures are already coordinated. This reduces commissioning time and simplifies troubleshooting.
The SANYO DENKI Product Range Distributed by RTA
- G Series — Product type: Compact servo system — Key features: GADWA dual-axis EtherCAT servo drive operating at 230 VAC and GADSA drive; GAM2A motors from 100 W to 1.5 kW with 23-bit multi-turn absolute encoders.
- R Series Servo Drives — Product type: Servo drives — Key features: RS3A at 230 VAC and RS3C at 400 VAC, with EtherCAT or analog input; RF2K four-axis EtherCAT servo drive operating at 48 VDC.
- R & Q Series Servo Motors — Product type: Servo motors — Key features: R2AA/R1AA at 230 VAC, R2CA at 400 VAC with power ratings up to 15 kW, R2GD at 48 VDC, and Q2AA.
Each servo motor must be paired with the appropriate servo drive specified in the SANYO DENKI documentation. RTA provides compatible motor-drive combinations on each product page.
Brushless Servo Drives: Communication Interfaces and Safety
SANYO DENKI servo drives are selected according to the available power supply and the required control interface:
- EtherCAT for coordinated multi-axis motion control via PLC or motion controller.
- Analog input or Step & Direction for more traditional control architectures.
Many models integrate the STO (Safe Torque Off) safety function, with SIL3 / PL e ratings, helping simplify machine safety design.
Dual-axis drives (GADWA) and four-axis drives (RF2K) reduce control cabinet space requirements and wiring complexity.
When selecting a servo drive, consider continuous and peak current ratings, acceleration duration, regenerative braking energy and any required external braking resistors, as well as heat dissipation inside the electrical cabinet.
Brushless Servo Motors: Beyond Power Ratings in Watts
When selecting a brushless servo motor, the most important parameters include continuous torque, peak torque, operating speed, rotor inertia and the motor's torque-speed characteristics.
SANYO DENKI servo motors reach speeds of up to 6,500 rpm on certain G Series models and are among the most compact in their class.
Encoder options range from 17-bit incremental encoders to 23-bit batteryless multi-turn absolute encoders.
48 VDC, 230 VAC and 400 VAC Servo Systems
- 48 VDC: RF2K servo drives and R2GD motors, designed for compact machines, mobile robots and low-voltage applications, with motor power ratings from 50 W to 300 W.
- 230 VAC: G Series and R Series RS3A servo drives paired with R2AA/R1AA motors. This is the broadest product range, suitable for most industrial automation machines.
- 400 VAC: RS3C servo drives and R2CA motors with power ratings up to 15 kW, designed for high-power motion axes and industrial machines with three-phase power supplies.
How to Size a Brushless Servo System
Servo system sizing starts with the motion profile: travel distance or angular displacement, cycle time, operating speed, acceleration and deceleration.
Additional parameters include load, friction, mechanical transmission, reflected inertia at the motor shaft and gravitational forces acting on vertical axes.
Using these values, the RMS torque requirement is compared with the motor's continuous torque rating, while peak torque demands are checked against the maximum permissible torque.
A typical example is a positioning axis with frequent starts and stops. A motor may appear suitable based on its rated power, but transient torque demands can exceed its thermal limits.
Conversely, an oversized motor may result in a less favorable inertia ratio and more complex tuning.
RTA Technical Support helps you verify the correct motor-drive combination, including braking resistors and machine safety requirements.
Batteryless Absolute Encoders: Restart Without Homing
With a batteryless multi-turn absolute encoder, the servo system retains position information even when the machine is powered off, eliminating the need for battery replacement and, when the system is correctly configured, a homing cycle at restart.
For multi-axis machines, this means reduced downtime and lower maintenance requirements.
Encoder resolution is only one factor affecting the final positioning accuracy of the axis, which also depends on gearboxes, mechanical backlash and shaft couplings.
Servo Motor with Planetary Gearbox
When an application requires higher output torque and lower output speed, SANYO DENKI servo motors can be combined with SG Series planetary gearboxes designed for brushless motors.
These gearboxes mount directly onto the motor, offer backlash values starting from 12 arcmin, and are manufactured and tested in Italy.
Applications of Brushless Servo Systems
Brushless servo systems are widely used in packaging machines, high-dynamic motion axes, multi-axis automation, robotics, positioning systems and special-purpose machinery.
For applications with less demanding motion requirements, consider stepper motors combined with RTA stepper motor drives.
RTA offers both technologies and helps you select the most suitable motion control solution based on your machine's opera
