The HG-SR502 is Mitsubishi Electric’s 5 kW low-inertia medium-capacity servo motor from the HG-SR series for the MELSERVO-J4 and MELSERVO-J3 servo amplifier platforms, providing 23.9 N·m rated torque at 2,000 rpm with a 22-bit multi-turn absolute encoder as standard — the high-torque 2,000 rpm variant of the 5 kW power class in the HG-SR series, designed for heavy-load direct-drive conveyor axes, large rotary indexing tables, and high-thrust linear drive systems where 5 kW of continuous servo power at lower rated speed provides higher shaft torque than the corresponding 3,000 rpm variant. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the HG-SR502?
The HG-SR502 is a Mitsubishi Electric MELSERVO HG-SR series servo motor providing 5 kW (5,000 W) continuous rated output at 2,000 rpm rated speed, with a peak torque of 71.6 N·m (3× rated torque). The «502» model designation identifies the 5 kW power class («50») at 2,000 rpm rated speed («2») within the HG-SR series numbering convention. Compatible with MR-J4-500A (pulse train) and MR-J4-500B (SSCNET III/H) servo amplifiers, the HG-SR502 is the standard motor-amplifier pairing for 5 kW, 2,000 rpm servo axes in MELSERVO-J4 systems. In J3 motor compatibility mode (PA22 = 1), the HG-SR502 is compatible with MR-J3-500A and MR-J3-500B amplifiers, enabling motor-only upgrade from legacy HC-SFS502 motors while retaining the J3 amplifier. At 23.9 N·m continuous rated torque — significantly higher than the HG-SR5024 (5 kW, 3,000 rpm, 15.9 N·m rated) — the HG-SR502 delivers the torque required for heavy-load direct drive or short gear ratio applications where high shaft torque at moderate speed is the primary axis requirement, eliminating the need for a large gear ratio reducer that would add backlash and compliance to the drivetrain.
Key Technical Specifications
- Model: HG-SR502
- Rated Output Power: 5 kW (5,000 W)
- Rated Torque: 23.9 N·m
- Rated Speed: 2,000 rpm
- Maximum Speed: 3,000 rpm
- Peak Torque: 71.6 N·m (3× rated)
- Rotor Inertia: 7.11 × 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. 17.5 kg
Compatibility & System Integration
The HG-SR502 is the primary motor for 5 kW axes in MELSERVO-J4 SSCNET III/H multi-axis systems managed by Q172DSCPU, Q173DSCPU, or RD77MS motion controllers — the motor connects to the MR-J4-500B servo amplifier via the standard MR-J3ENCBL encoder cable and MR-PWS1CBL motor power cable, with the amplifier receiving position commands from the motion controller at 0.888 ms or 0.444 ms SSCNET III/H cycle time. For pulse train commanded systems (QD75MH4, FX3U-2PG, or third-party CNC controller), the HG-SR502 pairs with the MR-J4-500A amplifier. In legacy J3-era installations, the HG-SR502 operates in J4 motor compatibility mode (PA22 = 1) with the MR-J3-500A or MR-J3-500B amplifier, providing the 22-bit encoder resolution upgrade from the original HC-SFS502 motor’s encoder while retaining the J3 amplifier — the encoder cable must be replaced with an HG-SR-compatible cable as the HC-SFS502 encoder cable connector is physically incompatible with the HG-SR502 encoder connector. For fully closed-loop applications with load-side linear encoder feedback, the HG-SR502 paired with MR-J4-500A/B and the CN2L dual encoder connection provides position loop closure at the load rather than at the motor shaft — compensating for ball screw pitch error, thermal expansion, and mechanical compliance in the drivetrain. The 71.6 N·m peak torque of the HG-SR502 requires the MR-J4-500A/B’s 69 A peak current output to be within its rated peak current — verify the amplifier’s peak current rating against the motor’s required peak torque-to-torque constant ratio before specifying any application that requires sustained peak torque acceleration duty.
Troubleshooting Guide
For HG-SR502 motors at 5 kW and 17.5 kg generating AL.50 (overload) alarms during operations previously performed without alarm, the most common cause in motors above 5 years of service is bearing wear increasing the motor’s running friction torque — the bearing friction adds to the load torque, reducing the available torque margin above the overload trip threshold. Verify bearing condition by listening for bearing noise (a rumbling or grinding sound during motor rotation) and measuring the motor’s no-load current via MR Configurator2’s diagnostic monitor — no-load current significantly higher than the motor’s rated no-load current specification indicates increased bearing friction. Bearing replacement in a 5 kW servo motor requires specialist servo motor repair facilities — do not attempt field bearing replacement without proper servo motor workshop equipment, as improper bearing installation causes immediate re-failure and may damage the motor shaft or encoder. For HG-SR502 motors generating AL.16 (encoder error) intermittently on large machining centre axes, the likely cause is encoder cable mechanical damage from repeated flexing during axis travel — inspect the cable at the point closest to the motor body where the cable exits the motor connector, as this is the highest mechanical stress point in moving-axis encoder cable installations. For a 5 kW motor generating thermal warnings (amplifier overtemperature model warning) during operations within the rated duty cycle, verify the motor mounting surface thermal conductivity — the HG-SR502’s large mass requires good thermal contact with the machine structure for efficient heat transfer. Incorrect mounting surface flatness (gap between motor flange and mount) causes significant thermal resistance that elevates motor operating temperature above the thermal model prediction.
Frequently Asked Questions
Q: What is the torque advantage of the HG-SR502 (2,000 rpm) over the HG-SR5024 (3,000 rpm) at the same 5 kW rating?
A: At the same 5 kW continuous power, the HG-SR502 provides 23.9 N·m at 2,000 rpm versus 15.9 N·m at 3,000 rpm for the HG-SR5024 — the 2,000 rpm winding provides 50% more shaft torque at rated speed, at the cost of lower maximum speed (3,000 rpm versus 5,000 rpm). For applications where the working speed is below 2,000 rpm and torque rather than speed is the primary requirement, the HG-SR502 enables direct drive or shorter gear ratios that reduce backlash and compliance compared to the higher gear ratio needed with the HG-SR5024 to develop the same output torque.
Q: Can the HG-SR502 be installed in any orientation (horizontal, vertical, inverted) without modification?
A: The HG-SR502 can be installed in any orientation — horizontal shaft, vertical shaft up, vertical shaft down, or inverted flange mount — without modification. The motor’s sealed bearings and IP65 shaft seal retain grease regardless of orientation. For vertical shaft-down installation, verify that the shaft seal is in good condition before installation, as any lubricant leakage from a worn shaft seal would drip directly onto the machine structure below in this orientation. Monitor the motor’s oil seal condition annually in vertical shaft-down installations, as the shaft seal in this orientation must retain lubricant against gravity continuously.
Q: What motor power cable cross-section is recommended for the HG-SR502 when the cable run from amplifier to motor exceeds 10 m?
A: For cable runs between 10 m and 20 m to the HG-SR502, use MR-PWS1CBL20M-A2-H (20 m heavy-duty flex motor power cable) or specify cable with minimum 4 mm² conductor cross-section for the U, V, W motor phases — the increased conductor cross-section reduces resistive voltage drop over the longer cable run, maintaining adequate motor terminal voltage at rated current. For cable runs above 20 m, consult Mitsubishi’s maximum cable length specifications for the MR-J4-500A/B and verify that the selected cable conductor cross-section keeps the voltage drop within the specified limit.
Do you need more references from this brand? Explore our full catalog of Mitsubishi here: https://atlantechdrives.com/manufacturers/mitsubishi/
