The HG-RR203K is Mitsubishi Electric’s 2 kW medium-inertia medium-capacity servo motor from the HG-RR series for the MELSERVO-J4 servo amplifier platform, providing 6.37 N·m rated torque at 3,000 rpm with a 22-bit multi-turn absolute encoder as standard — the 2 kW model in the HG-RR medium-inertia series, providing double the continuous output of the HG-RR103K for heavier-load conveyor drives, larger rotary table axes, and high-load winding and tension control applications where 2 kW of continuous servo power combined with the medium-inertia rotor’s improved load matching and velocity damping characteristics is required. The HG-RR203K is available through Atlantech Drives — quote within 24-48 hours, worldwide express shipping, 12-month warranty.
What Is the HG-RR203K?
The HG-RR203K is a Mitsubishi Electric MELSERVO HG-RR series servo motor providing 2 kW (2,000 W) continuous rated output at 3,000 rpm rated speed, with a peak torque of 19.1 N·m (3× rated torque). Compatible with MR-J4-200A (pulse train) and MR-J4-200B (SSCNET III/H) servo amplifiers, the HG-RR203K is the standard motor-amplifier pairing for 2 kW medium-inertia servo axes in MELSERVO-J4 multi-axis systems. At 3.40 × 10⁻⁴ kg·m² rotor inertia — approximately 2.5× higher than the equivalent-power HG-SR202 low-inertia motor (1.30 × 10⁻⁴ kg·m²) — the HG-RR203K provides significantly improved load inertia ratio for applications with high mechanical load inertia, reducing the load-to-motor inertia ratio proportionally and enabling stable servo operation where the HG-SR202 would exceed the recommended inertia ratio limit. The HG-RR203K is the current-generation replacement for the legacy HC-RFS203 medium-inertia motor used with MR-J3-200A/B amplifiers — in J4 motor compatibility mode (PA22 = 1 on the J3 amplifier), the HG-RR203K can replace an HC-RFS203 in an existing J3-era servo system while providing the 22-bit encoder resolution upgrade as a concurrent benefit.
Key Technical Specifications
- Model: HG-RR203K
- Rated Output Power: 2 kW (2,000 W)
- Rated Torque: 6.37 N·m
- Rated Speed: 3,000 rpm
- Maximum Speed: 4,500 rpm
- Peak Torque: 19.1 N·m (3× rated)
- Rotor Inertia: 3.40 × 10⁻⁴ kg·m² (higher than HG-SR202’s 1.30 × 10⁻⁴ kg·m²)
- Encoder: 22-bit multi-turn absolute (262,144 pulses/rev)
- Power Supply Voltage: 200 VAC (via compatible servo amplifier)
- Insulation Class: F (155°C maximum winding temperature)
- Protection Rating: IP65 (shaft seal and connector side)
- Mounting: Square flange, IEC standard
- Operating Temperature: 0°C to 40°C (ambient)
- Weight: Approx. 6.8 kg
Typical Industrial Applications
The HG-RR203K is deployed in 2 kW servo axis applications where the mechanical load’s high inertia or variable torque characteristics make the medium-inertia HG-RR series preferable to the low-inertia HG-SR series. In conveyor drive systems with variable product loads, the HG-RR203K’s higher rotor inertia acts as a flywheel that damps velocity perturbations caused by product loading events — a product landing on a moving conveyor belt driven by an HG-SR202 causes a visible velocity dip as the load torque instantaneously increases, while the same event on an HG-RR203K-driven conveyor produces a smaller, more gradual velocity response due to the additional rotor inertia. Web tension control systems (film unwinding, foil rewinding, paper converting) specify the HG-RR203K for the tension roll drive where the changing roll diameter constantly varies the reflected inertia — the medium inertia of the HG-RR203K provides better inertia matching across the winding cycle range compared to the HG-SR202. Large rotary indexing table drives with dial masses of 200–500 kg at 2 kW power specify the HG-RR203K when the table’s high inertia creates an inertia ratio above 30:1 with the HG-SR202, bringing the ratio within the recommended range with the HG-RR203K’s higher rotor inertia. In mixing and agitation drive applications where the load torque varies with mixer content viscosity and fill level, the HG-RR203K’s rotor inertia smooths the drive response to load torque fluctuations, producing more uniform mixing speed than a low-inertia motor of the same power.
Expert Tips
When commissioning the HG-RR203K in a conveyor drive application, configure the auto-tuning response level in MR Configurator2 based on the conveyor’s mechanical stiffness — for rigid short-span conveyors with steel chain drive, response level 6–10 is typically achievable; for long-span belt conveyors with significant belt compliance, start at level 3–5 and increase cautiously, monitoring for belt resonance vibration. The HG-RR203K’s higher rotor inertia compared to the HG-SR202 means the auto-tuning algorithm will identify a lower load inertia ratio for the same mechanical system, resulting in higher-gain servo settings that can excite belt resonance if the response level is set too high for the belt compliance. For winding applications using the HG-RR203K in torque control mode, set the torque ramp rate (parameter PC17 in the MR-J4 parameter set) to limit the rate of torque change during web break events — a sudden tension loss causes the torque-controlled motor to accelerate rapidly if the torque command is not immediately reduced, and a finite torque ramp-down rate provides time for the web break detection logic to respond before the motor overspeeds. Monitor the HG-RR203K’s actual speed during commissioning of winding applications with MR Configurator2’s waveform monitor — the motor speed should remain within ±5% of the commanded speed throughout the winding cycle; speed deviations larger than this indicate servo tuning issues or inadequate torque margin in the application sizing.
Frequently Asked Questions
Q: Can the HG-RR203K replace an HC-RFS203 directly in an MR-J3-200A pulse train system?
A: Yes, in J4 motor compatibility mode. Set the MR-J3-200A parameter PA22 = 1 to enable J4 motor support, then set the motor code parameter to the HG-RR203K code in MR Configurator2. Replace the HC-RFS203 encoder cable with an HG-RR-compatible encoder cable (MR-J3ENCBL series, appropriate length) — the HC-RFS203 encoder cable connector is physically incompatible with the HG-RR203K encoder connector. After motor replacement, re-run auto-tuning as the HG-RR203K’s rotor inertia differs slightly from the HC-RFS203, requiring gain recalibration for optimal servo performance.
Q: What is the maximum speed of the HG-RR203K, and does it differ from the equivalent HG-SR202?
A: The HG-RR203K’s maximum speed is 4,500 rpm versus 5,000 rpm for the HG-SR202. The lower maximum speed of the medium-inertia HG-RR series reflects the higher centrifugal stress on the larger-diameter rotor at speed — the rotor’s higher moment of inertia requires more conservative speed limits to maintain mechanical integrity of the rotor lamination stack and magnet retention. For applications requiring the full 5,000 rpm speed at 2 kW, the HG-SR202 must be specified.
Q: Does the HG-RR203K support a brake option for vertical axis holding?
A: Yes. The HG-RR203K is available with an electromagnetic holding brake (HG-RR203KB) — a spring-applied, power-released brake providing fail-safe holding when the 24 VDC brake power supply is removed. The brake holding torque for the 2 kW HG-RR frame is specified in the HG-RR series hardware manual and must exceed the gravitational holding torque of the vertical axis load at all positions within the axis travel range.
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