The HG-SR43 is Mitsubishi Electric’s 400 W low-inertia medium-capacity servo motor from the HG-SR series for the MELSERVO-J4 and MELSERVO-J3 servo amplifier platforms, providing 1.27 N·m rated torque at 3,000 rpm with a 22-bit multi-turn absolute encoder as standard — doubling the continuous output of the HG-SR23 in the same motor family, designed for CNC machining centre feed axes, robotic arm drives, and packaging machinery servo axes where 400 W of continuous servo power with high resolution absolute position feedback is required. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the HG-SR43?
The HG-SR43 is a Mitsubishi Electric MELSERVO HG-SR series servo motor providing 400 W (0.4 kW) continuous rated output at 3,000 rpm rated speed, with a peak torque of 3.82 N·m (3× rated torque). The motor is compatible with MR-J4-40A (pulse train input) and MR-J4-40B (SSCNET III/H network) servo amplifiers as the standard motor-amplifier pairing for 400 W axes in MELSERVO-J4 servo systems. The 22-bit multi-turn absolute encoder provides 262,144 pulses per revolution, delivering approximately 19 nanometres of linear position resolution when combined with a standard 5 mm pitch ball screw — substantially finer than the 131,072 pulses/rev of legacy J3-era 17-bit encoders, improving fine positioning accuracy in precision machining and measurement applications. In J3 motor compatibility mode (parameter PA22 = 1), the HG-SR43 is also compatible with MR-J3-40A and MR-J3-40B servo amplifiers, enabling motor-only upgrade from legacy HC-KFS43 or HC-MFS43 motors while retaining the existing J3 amplifier infrastructure — a cost-effective upgrade path that provides 22-bit resolution improvement without requiring amplifier replacement.
Key Technical Specifications
- Model: HG-SR43
- Rated Output Power: 400 W (0.4 kW)
- Rated Torque: 1.27 N·m
- Rated Speed: 3,000 rpm
- Maximum Speed: 6,000 rpm
- Peak Torque: 3.82 N·m (3× rated)
- Rotor Inertia: 0.148 × 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. 1.3 kg
Typical Industrial Applications
The HG-SR43 at 400 W is the most commonly specified motor for mid-range servo axis applications in multi-axis CNC and assembly machine systems. In CNC machining centres with 3 to 5 servo axes, the HG-SR43 frequently drives the Z-axis (vertical spindle head) or the shorter X/Y axis travels where 400 W provides adequate thrust for the axis mass at rapid traverse speeds without the larger frame and higher inertia of the 750 W HG-SR73. In robotic wrist axes (axes 4, 5, 6) of 10–20 kg payload industrial robots, the HG-SR43 provides the torque required for end-of-arm tooling positioning and orientation changes at the programmed speeds, where the light wrist structure mass is well matched to the 400 W motor’s continuous torque rating. Rotary indexing tables with 100–250 mm dial diameters in multi-station assembly machines commonly specify the HG-SR43 for the table drive axis, where the dial mass and tooling inertia combined require 1.27 N·m of continuous torque at the indexing speed. In high-speed labelling and printing machines, the HG-SR43 drives the print head carriage and product transport axes where 400 W and 3,000 rpm combine to deliver the required linear traverse speed on standard ball screw or belt drive mechanisms. Food and pharmaceutical packaging machines use the HG-SR43 for form, fill, and seal station servo drives, where the motor’s IP65 protection provides adequate resistance to the incidental water exposure present in hygienic packaging environments — though high-pressure washdown applications require additional motor sealing beyond the standard IP65.
Maintenance Tips
The HG-SR43’s 22-bit absolute encoder battery (MR-BAT6V1SET, installed in the servo amplifier rather than in the motor) should be replaced every 3–5 years at 25°C ambient, or more frequently in high-temperature environments — the battery retains the multi-turn absolute position counter during power-off, and battery depletion causes AL.25 (absolute position erased) alarm requiring a homing cycle at next power-up. Monitor the battery status via the servo amplifier’s AL.9E (battery warning) indicator or via MR Configurator2’s diagnostic display — replace the battery when AL.9E activates, before AL.25 occurs. For HG-SR43 motors installed on moving axes (linear slides, robot arms), inspect the encoder cable annually for jacket cracking at the point where the cable exits the motor body — bending fatigue causes cable jacket cracking at the highest-stress bend point, typically within 100–200 mm of the motor connector. Replace encoder cables showing any visible jacket damage, as a partially failed cable can cause sudden encoder communication loss at a critical position in the servo control cycle. The HG-SR43’s mounting flange bolts should be checked for tightness at the annual maintenance interval — vibration from the machining environment can gradually loosen mounting bolts, causing the motor body to shift slightly in the mount and introducing position errors that appear intermittent and are difficult to diagnose without direct physical inspection of the motor mount.
Frequently Asked Questions
Q: What is the maximum allowable ambient temperature for the HG-SR43 in continuous operation at rated torque?
A: The HG-SR43 is rated for continuous operation at rated torque up to 40°C ambient temperature. Above 40°C, the motor’s continuous rated torque must be derated according to the derating curve in the HG-SR series hardware manual — at 55°C ambient, the allowable continuous torque is typically reduced to approximately 80% of the rated value. For machine installations where the motor ambient temperature regularly exceeds 40°C (such as motors mounted near heat sources or in poorly ventilated enclosures), calculate the derated continuous torque and verify it still meets the application’s requirement, or select the next larger motor frame to provide adequate torque margin at the elevated ambient temperature.
Q: Can the HG-SR43 be used with a planetary gearbox for low-speed high-torque applications?
Q: Is the HG-SR43 available with a different winding for 400 VAC servo amplifier compatibility?
A: Yes. The HG-SR43 standard model is designed for 200 VAC servo amplifier systems (MR-J4-40A/B, etc.). For 400 VAC system compatibility, the HG-SR434 variant (the «4» suffix denoting 400 V class winding) is the appropriate specification — compatible with MR-J4-40A4 and MR-J4-40B4 400 V class amplifiers. The rated torque, speed, and encoder specification are identical between the 200 V and 400 V variants; only the winding voltage rating differs.
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