The MR-J3-10A is Mitsubishi Electric’s 100 W MELSERVO-J3 series servo amplifier for 200 V single-phase or three-phase AC power supply with pulse train position command input — the smallest model in the MR-J3-A pulse train sub-series, providing 100 W continuous servo control at 1.1 A for HC-KFS13, HC-MFS13, and equivalent 100 W servo motors in active MR-J3-based servo systems requiring direct maintenance replacement of failed units. Atlantech Drives holds stock of the MR-J3-10A. Contact us for fast worldwide delivery and competitive pricing.
What Is the MR-J3-10A?
The MR-J3-10A is a MELSERVO-J3 series servo amplifier providing 100 W (0.1 kW) continuous output power for Mitsubishi HC-KFS13, HC-MFS13, and equivalent 100 W servo motors equipped with the MR-J3’s 17-bit multi-turn absolute encoder (131,072 pulses/rev). The «10» in the model designation identifies the 100 W power class within the MR-J3-A series naming convention, while the «A» suffix designates the pulse train input command interface accepting position command pulses from an external host controller via open-collector or differential RS-422A pulse input at up to 4 Mpps. As the entry-level model in the MR-J3-A range, the MR-J3-10A has the same compact 40 mm housing width as the MR-J3-20A (200 W), enabling dense multi-axis panel layouts for small-motor servo systems. The amplifier implements the MELSERVO-J3 three-loop servo control architecture with 2 kHz current loop bandwidth, AVSC (Advanced Vibration Suppression Control, first generation) single notch filter, and auto-tuning via MR Configurator or MR Configurator2. Like all MR-J3-A amplifiers, the MR-J3-10A does not include a built-in STO safety function — IEC 62061 / EN ISO 13849 safety compliance requires external safety contactors in the main circuit wiring. The MR-J3-10A has been superseded by the MR-J4-10A and is specified for direct maintenance replacement only.
Key Technical Specifications
- Model: MR-J3-10A
- Rated Output Power: 100 W (0.1 kW)
- Power Supply: 200–240 VAC single-phase or three-phase, 50/60 Hz
- Continuous Output Current: 1.1 A
- Maximum Output Current: 3.3 A (3× continuous peak)
- Compatible Servo Motors: HC-KFS13, HC-MFS13, HG-KR13 (J4 motor, J3 compat. mode)
- Command Interface: Pulse train input (open-collector or differential RS-422A)
- Maximum Input Pulse Frequency: 4 Mpps (differential), 200 kpps (open-collector)
- Encoder Interface: Serial 17-bit absolute encoder (131,072 pulses/rev)
- Safety Function: None built-in (external safety contactor required)
- Regenerative Brake: Built-in
- Communication: USB (MR Configurator2), RS-422 (cascade)
- Operating Temperature: 0°C to 55°C
- Dimensions (W × H × D): 40 mm × 150 mm × 138 mm
- Weight: Approx. 0.7 kg
Architecture & Design Overview
The MR-J3-10A implements the MELSERVO-J3 three-loop digital servo control architecture at 100 W scale — the position loop compares the commanded pulse count from the host controller to the motor encoder feedback, the speed loop regulates motor velocity to eliminate position error, and the current loop regulates motor winding current to deliver commanded torque, all processing at 2 kHz bandwidth within the J3 control DSP. At 100 W and 1.1 A continuous, the MR-J3-10A’s power stage uses the smallest IGBT module in the MR-J3-A series — compact enough to achieve the 40 mm housing width that enables dense multi-axis panel layouts in semiconductor, electronics assembly, and precision instrument equipment where many small servo axes must fit within a constrained panel width. The MR-J3-10A’s auto-tuning function identifies the load inertia ratio from the motor’s response to controlled acceleration-deceleration test cycles and sets servo gains to achieve stable response at the identified inertia ratio. For 100 W axes, the motor rotor inertia (HC-KFS13: 0.0283 × 10⁻⁴ kg·m²) is very small — even moderate load inertia results in a high inertia ratio that can destabilise the servo response if gains are set too high. The auto-tuning algorithm starts at a conservative response level (level 1) and increases incrementally — always verify settled servo response by monitoring the position error waveform in MR Configurator2 after auto-tuning before operating at the application’s full motion profile. The MR-J3-10A’s AVSC single notch filter can suppress one mechanical resonance frequency — if the 100 W axis exhibits two distinct resonance frequencies (common in lightweight mechanisms with multiple compliance points), manual notch filter frequency selection or the MR-J4-10A’s AVSC II dual notch filter is required.
Replacement & Upgrade Notes
The MR-J3-10A is discontinued from Mitsubishi production and available from aftermarket inventory. The direct current-generation upgrade is the MR-J4-10A — physically compatible (same 40 mm housing width and compatible mounting pattern), accepting the same HC-KFS13 and HC-MFS13 motors in J3 motor compatibility mode (parameter PA22 = 1), and accepting the same differential pulse train wiring from the host controller without modification. The MR-J4-10A upgrade provides 22-bit encoder resolution (versus MR-J3’s 17-bit), built-in STO safety function (eliminating the external safety contactor requirement), AVSC II dual notch filter for superior resonance suppression, and improved auto-tuning convergence. Use MR Configurator2’s parameter conversion function to create an initial MR-J4-10A parameter set from the existing MR-J3-10A parameter file before the upgrade — this reduces commissioning time significantly compared to tuning from factory defaults. For facilities with multiple MR-J3-10A units in active semiconductor or electronics assembly equipment, plan a proactive amplifier-by-amplifier replacement programme during scheduled maintenance windows — the 100 W power class means individual unit failure causes complete axis loss for precision assembly processes that cannot tolerate any positioning inaccuracy from a degraded amplifier.
Frequently Asked Questions
Q: Can the MR-J3-10A be used with a current-generation HG-KR13 servo motor without replacing the amplifier?
A: Yes. The MR-J4-generation HG-KR13 motor with 22-bit absolute encoder is compatible with the MR-J3-10A amplifier in J3 motor compatibility mode — set parameter PA22 = 1 in the MR-J3-10A to enable J4 motor support. The encoder cable must be replaced with an HG-KR-compatible cable (MR-J3ENCBL series), as the HC-KFS13’s encoder cable connector is physically incompatible with the HG-KR13’s encoder connector. The motor operates with 22-bit encoder resolution (131,072 → 262,144 pulses/rev improvement), providing finer position resolution while the J3 amplifier gains remain tuned to the motor’s physical characteristics.
Q: Does the MR-J3-10A support speed control mode for spindle or tension drive applications at 100 W?
A: Yes. The MR-J3-10A supports speed control mode via the analogue speed command input (VC terminal, ±10 VDC) with the position loop disabled. In speed control mode, the motor speed is regulated proportional to the analogue command voltage, enabling the MR-J3-10A to drive small spindle, fan, or tension control axes where velocity regulation is the primary control requirement. Select speed control mode via amplifier parameter PA01.
Q: What is the maximum encoder cable length between an MR-J3-10A and its servo motor?
A: The MR-J3-10A supports encoder cable lengths up to 30 metres using standard Mitsubishi MR-J3ENCBL or MR-EKCBL series encoder cables. For cable lengths above 30 metres, the encoder signal may be attenuated beyond the J3 encoder receiver’s specification, causing intermittent AL.16 encoder errors. For applications requiring motor-to-amplifier distances above 30 metres, the MR-J3-10A’s maximum distance is the binding constraint and a relay/repeater or alternative mounting arrangement must be considered.
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