The HG-KR23 is a 200 W low-inertia servo motor from Mitsubishi Electric, belonging to the HG-KR series engineered for use exclusively with MELSERVO-J4 servo amplifiers. Its compact 40 mm square flange and low rotor inertia make it the preferred choice for high-speed, high-cycle positioning axes in semiconductor, electronics assembly, and precision automation equipment. Available now at Atlantech Drives with worldwide express delivery and 12-month warranty — complete our quote form for pricing and availability.
What Is the Mitsubishi HG-KR23?
The HG-KR23 belongs to the HG-KR low-inertia sub-family within the MELSERVO-J4 motor ecosystem. The -23 designation indicates a rated output of 200 W at a rated speed of 3,000 RPM. Compared to the medium-inertia HG-MR series at equivalent power, the HG-KR23 features a significantly smaller rotor moment of inertia, which translates directly to faster acceleration and deceleration times and shorter settling times for point-to-point positioning — a critical performance parameter for high-throughput pick-and-place, wire bonding, and chip mounting applications. The motor integrates a 22-bit absolute encoder (4,194,304 pulses/rev) as standard, shared across the entire J4 motor range.
Key Technical Specifications
- Rated output: 200 W
- Rated speed: 3,000 RPM
- Maximum speed: 6,000 RPM
- Rated torque: 0.64 N·m
- Peak torque: 1.91 N·m (instantaneous)
- Rotor moment of inertia: 0.0388 × 10⁻⁴ kg·m² (ultra-low inertia)
- Encoder: 22-bit absolute (4,194,304 pulses/rev)
- Flange size: 40 mm square
- Shaft: Straight shaft without key (standard); with key optional (-S05 suffix)
- Ingress protection: IP65 (excluding shaft seal)
- Vibration class: V10
- Compatible amplifier: MR-J4-20A, MR-J4-20B, MR-J4W□-□□B (200 W rating)
- Operating temperature: 0 to 40°C (ambient)
Architecture & Design Overview
The HG-KR23’s performance advantage over medium and high-inertia motors at equivalent power stems from its rotor design philosophy: the HG-KR series uses a smaller-diameter, longer rotor with a concentrated winding configuration that minimises rotor mass while maintaining the required torque constant. This geometry reduces the mechanical time constant — the ratio of rotor inertia to motor damping — which governs how quickly the motor responds to a velocity command step. For a J4 amplifier tuned to the HG-KR23’s inertia ratio, the one-sigma settling time for a 1 mm positioning move on a direct-drive linear stage is typically 30–50% shorter than an equivalent HG-MR motor at the same power rating. The 22-bit absolute encoder eliminates the need for a homing routine at power-up, preserving absolute position across power cycles when an MR-J4 battery backup unit (MR-BAT6V1SET) is installed. The encoder serial interface connects via a single 4-wire cable to the MR-J4 amplifier’s CN2 connector, simplifying wiring compared to older incremental encoder systems requiring separate A/B/Z differential pairs.
Replacement & Upgrade Notes
- The HG-KR23 is the direct J4-generation replacement for the HC-LPS13 (100 W) and HC-LPS23 (200 W) motors used with MR-J2S amplifiers. However, the encoder interface, connector pinout, and flange dimensions differ — a direct mechanical and electrical swap is not possible without adapting the motor cable (use Mitsubishi MR-J4JCBL□M-A2-H cable set) and verifying that the mounting flange hole pattern matches.
- When upgrading from MR-J3 + HG-MR23 to MR-J4 + HG-KR23, note that the HG-KR23’s lower inertia will require re-tuning the J4 amplifier’s gain settings (auto-tuning response level Pr.PA08). The inertia ratio will change, and gains optimised for the HG-MR23 will typically result in excessive overshoot if applied directly to the HG-KR23 without re-tuning.
- For applications previously using the HG-KR23J (with key and tapped shaft), verify that the coupling or pulley bore and keyway dimensions are compatible before placing an order — the standard HG-KR23 has a plain shaft without key.
Frequently Asked Questions
Q: Is the HG-KR23 compatible with MR-J3 or MR-J2S amplifiers?
A: No. The HG-KR series uses the MELSERVO-J4 22-bit encoder interface, which is electrically and mechanically incompatible with MR-J3 and MR-J2S amplifiers. For J3 systems, the equivalent low-inertia motor is the HG-MR series; for J2S, the HC-LPS series.
Q: What is the difference between HG-KR23 and HG-KR13?
A: The HG-KR13 is rated at 100 W (0.32 N·m rated torque) and pairs with the MR-J4-10A/B amplifier. The HG-KR23 is rated at 200 W (0.64 N·m) and pairs with the MR-J4-20A/B. Both share the same 40 mm flange and 22-bit encoder, but the KR23 has a longer rotor stack to achieve the higher torque output.
Q: Does the HG-KR23 require forced cooling at rated load?
A: No. The HG-KR23 is self-cooled (natural convection) at rated continuous output. No external fan is required for operation within the specified ambient temperature range of 0–40°C. At ambient temperatures between 40°C and 55°C, output deration applies — consult the MELSERVO-J4 motor catalogue derating curves.
Do you need more references from this brand? Explore our full catalog of Mitsubishi here: https://atlantechdrives.com/manufacturers/mitsubishi/
