Home > RA3 Servo Drive

RA3 Series — AC Servo Drive (1.6–45A, EtherCAT / Pulse / Analog)

General Specifications

Item	Specifications
Series	RA3 AC Servo Drive
Control Method	IGBT PWM, sine-wave current drive
Rated Current	1.6A – 45A
Input Voltage	1-ph 220V / 1-3 ph 220V / 3-ph 220V / 3-ph 380V
Encoder Type	Communication encoder (RS485)
Control Modes	Position, speed, torque
Protection	IP20
Ambient Temperature	0 ~ 55°C (derate above 45°C)
Frame Sizes	Size A to F

Get a Quick Quote DOWNLOAD

introduction

Input Voltage	Rated Current Range	Current Steps
Single-phase 220V	1.6 – 6.6 A	1.6 / 2.8 / 5.5 / 6.6 A
Single / three-phase 220V	7.6 – 12 A	7.6 / 12 A
Three-phase 220V	18 – 27 A	18 / 22 / 27 A
Three-phase 380V	3.5 – 45 A	3.5 / 5.4 / 8.4 / 12 / 16.5 / 21 / 25.7 / 32 / 38 / 45 A

*Rated current is selected to match the servo motor. Model code example: RA3 E - 5R5 L (series - control method - current - input voltage). We supply the drive matched and tested with the motor.

FAQs

What is the RA3 AC servo drive?

The RA3 is our full-range AC servo drive series, an AC servo motor driver for industrial motion. It uses IGBT PWM sine-wave current control with a communication-type (RS485) encoder interface, and covers rated currents from 1.6A to 45A across 220V and 380V supplies. It runs position, speed, and torque modes, and is built to pair with our AC servo motors as a matched, tested set.

What control methods does the RA3 support?

The RA3 comes in three control versions, set by the model code: E is EtherCAT (bus control), P is pulse, and A is pulse plus analog command. Choose E for networked multi-axis machines, P for simple pulse/direction control, and A when you also need an analog speed or torque reference.

What current and voltage range does the RA3 cover?

Rated current runs from 1.6A to 45A. The supply options are single-phase 220V (1.6–6.6A), single/three-phase 220V (7.6–12A), three-phase 220V (18–27A), and three-phase 380V (3.5–45A). The 380V band carries the largest models, so the RA3 reaches higher power than the RS3 series.

What fieldbus and communication does it support?

The EtherCAT version (RA3E) follows IEC 61158 Type12 and IEC 61800-7 CiA 402, with 100BASE-TX dual RJ45 ports, a 100Mbps line, and a 250µs–10000µs cycle. It supports CiA 402 modes PP, PV, PT, HM, CSP, CSV, and CST. The pulse versions use RS485 Modbus, and the A version adds CANopen. A USB Type-C port is provided for PC tuning on all models.

What protection and safety functions are built in?

Protection covers over-voltage, under-voltage, phase loss, over-current, overload, over-speed, and encoder disconnection. A dynamic brake acts on power loss, alarm, servo-off, and over-travel, and regenerative braking is built in on all but the smallest Size A models. STO is available as an option, along with full-closed-loop and high-protection variants.

How is the RA3 different from the RS3 series?

The RA3 is the full-range, higher-power series: 1.6A to 45A, including three-phase 220V and the large 380V models, with CANopen on the analog version. The RS3 is the compact series, 1.6A to 12A, for small and mid-size axes. Both share the same control platform and encoder interface; see the rs3-servo-drive page for the compact option.

Does the drive come matched to the motor?

Yes. As an AC servo drive manufacturer and supplier, we provide the RA3 drive sized and tuned to the servo motor as a tested set, so the current rating, commutation, and gains are configured before delivery. The drive ships ready to run with the matched motor.

RA3 AC Servo Drive: Full-Range EtherCAT, Pulse, and Analog Control

The RA3 servo drive is our full-range AC servo drive series, covering rated currents from 1.6A to 45A across single-phase 220V, three-phase 220V, and three-phase 380V supplies. It uses IGBT PWM sine-wave current control with a communication-type (RS485) encoder interface, and comes in EtherCAT, pulse, and pulse-plus-analog versions. Because it reaches the large 380V models, the RA3 is the higher-power choice in our drive line, pairing with servo motors from the small 60mm frame up to the large 180mm. Every RA3 ships matched and tested with its motor.

Key Specifications at a Glance

Parameter	Specification
Series	RA3 AC servo drive
Rated Current	1.6 – 45 A
Input Voltage	220V / 380V (1-ph and 3-ph)
Control Method	IGBT PWM, sine-wave current
Control Versions	E (EtherCAT), P (pulse), A (pulse + analog)
Encoder Interface	Communication encoder (RS485)
Control Modes	Position, speed, torque
Protection Rating	IP20

Three Control Versions

The RA3 model code sets the control method, so one series covers most machine architectures:

RA3E — an EtherCAT servo drive for networked multi-axis machines with a central controller. Follows IEC 61158 Type12 and CiA 402.
RA3P — a pulse servo drive using pulse/direction control, for straightforward single-axis setups driven by a pulse source.
RA3A — pulse plus analog command, when an analog speed or torque reference is also needed; this version adds CANopen.

Communication and Fieldbus

The EtherCAT version uses 100BASE-TX over dual shielded RJ45 ports at 100Mbps, with a 250µs to 10000µs cycle and DC synchronization. It supports CiA 402 modes PP, PV, PT, HM, CSP, CSV, and CST, so it drops into standard EtherCAT motion controllers. The pulse versions communicate over RS485 Modbus for parameter setup, and a USB Type-C port is provided on every model for PC tuning software.

Protection and Safety

Every RA3 drive includes a full protection set — over-voltage, under-voltage, phase loss, over-current, overload, over-speed, and encoder disconnection. A dynamic brake engages on power loss, alarm, servo-off, and over-travel, and regenerative braking is built in on all but the smallest Size A models. Optional functions, set in the model code, include STO (safe torque off), full-closed-loop control (F), the full-function package (FS), and a high-protection build (HP).

Typical Applications

The RA3 suits a broad range of industrial motion, from small benchtop axes to large machines:

CNC machine tools — multi-axis feed and spindle positioning over EtherCAT.
Automated production lines — networked, synchronized multi-axis motion.
Packaging and converting — high-throughput indexing and registration.
Robotics and handling — coordinated joint and axis control.
Electronics and semiconductor — precise small-stage positioning.
Large machinery — high-power 380V axes on presses, extruders, and gantries.

RA3 vs RS3: Which Servo Drive?

Both share the same control platform and encoder interface. The difference is power coverage:

	RA3	RS3
Rated Current	1.6 – 45 A	1.6 – 12 A
Input Voltage	220V / 380V	220V / 380V
Control Versions	E / P / A	E / P
Best For	Full range, higher power	Compact, small to mid axes

Choose the RA3 when you need the full current range, higher-power 380V models, or the analog (A) version. For small to mid-size axes in a compact package, see the RS3 servo drive. Both pair with our AC servo motor range as a matched set.

Model Code

The RA3 model code reads series – control method – rated current – input voltage – option. For example, RA3E-5R5L is an RA3 EtherCAT drive, 5.5A, single-phase 220V. Current ratings use the R notation (5R5 = 5.5A, 12R = 12A). As the factory, we help you select the right code against your motor and supply, support custom configurations for OEM projects, and ship the drive matched and tested with the motor.