0.75 kW servo with brake for high-duty-cycle positioning
The HG-KR73B is a Mitsubishi Electric rotary servo motor rated at 0.75 kW continuous output with a rated speed of 3000 r/min and a maximum speed of 6000 r/min. It delivers 2.4 N·m rated torque and a peak of 8.4 N·m for acceleration and deceleration phases. The built-in electromagnetic brake holds the load at rest when power is removed, which is essential for vertical-axis applications where the load must not drop during a power loss or at standstill. It is part of the HG-KR low-inertia, small-capacity series, designed for applications requiring fast acceleration and precise positioning with a recommended load-to-motor inertia ratio of 17 times or less.
Encoder and feedback for absolute position tracking
The motor carries a 22-bit absolute position incremental shared encoder, giving 4,194,304 pulses per revolution. This resolution allows the servo drive to know the rotor position immediately on power-up without a homing sequence, saving cycle time on multi-axis machines. The encoder is absolute, so the position is retained even after a power cycle — no need to re-reference the axis on every startup. The 22-bit resolution delivers fine positioning down to sub-arcminute increments.
Matching servo amplifiers and interface options
This motor works with several Mitsubishi MR-J4 series servo amplifiers depending on the network interface required. For SSCNET/H networks, pair it with the MR-J4-70B or MR-J4-70B-RJ. For general-purpose pulse-train control, use the MR-J4-70A or MR-J4-70A-RJ. For a 2-axis integrated SSCNET/H drive, use the MR-J4W2-77B or MR-J4W2-1010B. The command interface options cover CC-Link IE field network, SSCNET/H, 2-axis integrated SSCNET/H, and general-purpose interfaces, so the same motor can be specified across different control architectures by selecting the appropriate amplifier.
Environmental sealing and mounting constraints
The motor is rated IP65 (all enclosed self-cooled construction), meaning it is dust-tight and protected against water jets from any direction. This makes it suitable for washdown environments and areas with moderate coolant exposure, though it lacks an oil seal — if oil mist or splash is present, specify the variant with an oil seal (HG-KR_J). Ambient operating temperature is not explicitly stated in the spec, but the thermal class is 130 (B), so the winding insulation is rated for a 130 °C hot-spot temperature. The motor is intended for indoor use without corrosive gas, flammable gas, oil mist, or dust, and at altitudes up to 2000 m. Vibration resistance is 49 m/s² in both X and Y axes, and the vibration class is V10. The allowable radial load on the shaft is 392 N and thrust load is 147 N — respect these limits to avoid bearing fatigue.
Inertia and dynamic response
The rotor moment of inertia is 1.37 × 10⁻⁴ kg·m², placing it in the low-inertia category. Combined with the 17× recommended load inertia ratio, this motor is well suited for applications requiring rapid direction changes and short settling times, such as pick-and-place or high-speed indexing. Rated current is 4.8 A and maximum current is 17 A, so the amplifier must be sized to supply the peak current during acceleration. The power supply capacity required is 1.3 kVA.
The HG-KR73B is sourced to order through independent distribution channels.