The MR-J4-11KA is Mitsubishi Electric’s 11 kW MELSERVO-J4 series servo amplifier for three-phase 200 V AC power supply, providing closed-loop servo control at continuous rated output current of 56 A for Mitsubishi HG-UR and HG-JR series high-power servo motors — the largest single-amplifier model in the MR-J4-A 200 V pulse train input series, designed for the most demanding industrial servo applications including large CNC machining centre spindle and feed axis drives, heavy-load industrial robot base axes, and large-format automated material handling systems where 11 kW of continuous servo power represents the maximum capacity deliverable in a standalone servo amplifier configuration. Available now at Atlantech Drives with worldwide express delivery and 12-month warranty — complete our quote form for pricing and availability.
What Is the MR-J4-11KA?
The MR-J4-11KA is a MELSERVO-J4 series servo amplifier providing 11 kW (11,000 W) continuous output power — the maximum continuous output power in the MR-J4-A 200 V single-unit configuration — for Mitsubishi servo motors in the HG-UR11K, HG-JR11K2, and equivalent 11 kW servo motor models. The «11K» in the model designation denotes 11 kW, while the «A» suffix indicates the pulse train input command interface accepting position commands from an external controller at up to 4 Mpps via differential RS-422A or 200 kpps via open-collector. The amplifier’s power stage is designed exclusively for three-phase 200–240 VAC supply — the 56 A continuous current rating at 11 kW output makes single-phase operation impractical and potentially damaging, requiring three-phase supply with appropriately rated circuit protection (typically 75–100 A fusing per phase). The MR-J4-11KA implements all standard MR-J4 servo control features: 22-bit multi-turn absolute encoder support, Advanced Vibration Suppression Control II with automated resonance detection, STO safety function (IEC 61800-5-2), and full MR Configurator2 USB connectivity for commissioning, tuning, and waveform monitoring. For applications requiring more than 11 kW of servo power in a single axis, Mitsubishi’s multi-axis drive configuration using two MR-J4-11KA amplifiers with a power sharing bus, or the higher-power MR-J4W-series common bus amplifiers, must be specified.
Key Technical Specifications
- Model: MR-J4-11KA
- Rated Output Power: 11 kW (11,000 W)
- Power Supply: 200–240 VAC three-phase only, 50/60 Hz
- Continuous Output Current: 56.0 A
- Maximum Output Current: 168.0 A (3× continuous peak)
- Compatible Servo Motors: HG-UR11K, HG-JR11K2, HG-UR11K4 and equivalent
- 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 22-bit absolute encoder (262,144 pulses/rev)
- Safety Function: STO (Safe Torque Off), IEC 61800-5-2
- Regenerative Brake: External MR-RB series resistor required for high-regeneration applications
- Communication: USB (MR Configurator2), RS-422 (multi-axis cascade)
- Operating Temperature: 0°C to 55°C (fan cooling, forced air)
- Dimensions (W × H × D): 200 mm × 320 mm × 230 mm
- Weight: Approx. 7.5 kg
Compatibility & System Integration
The MR-J4-11KA integrates with the same host controller ecosystem as all MR-J4-A variants — Mitsubishi QD75MH4 and QD75D4 MELSEC-Q positioning modules, FX3U-2PG and FX3U-1PG FX3U positioning adapters, and any third-party CNC controller or motion controller capable of generating differential pulse train output at up to 4 Mpps. For MELSEC-Q systems using the QD75MH4 positioning module, the MR-J4-11KA accepts the QD75MH4’s differential pulse output directly, enabling 4-axis coordinated positioning with 11 kW servo axes — a configuration used in large CNC gantry machining centres where the X and Y axes each require 11 kW servo power for heavy workpiece cutting forces. The MR-J4-11KA is also compatible with the FANUC 0i-MF and FANUC 30i CNC controllers via differential pulse interface, enabling Mitsubishi servo motors to be driven from a FANUC CNC in machine retrofits where the CNC controller is retained but the servo amplifiers and motors are replaced. In multi-axis systems with the MR-J4-11KA, use Mitsubishi’s MR-J3-D05 multi-axis servo controller cable or equivalent RS-422 cascade wiring to connect multiple MR-J4 amplifiers in a master-slave cascade for simultaneous parameter writing from MR Configurator2 — this simplifies commissioning when all axes share common parameter settings. The MR-J4-11KA’s STO safety function integrates with Mitsubishi’s safety PLC modules (Q series safety) via hardwired safety relay or direct STO input connection, meeting IEC 61800-5-2 SIL2 requirements for safe torque cutoff on emergency stop.
Replacement & Upgrade Notes
The MR-J4-11KA is the current-generation MELSERVO-J4 replacement for the MR-J3-11KA (previous MELSERVO-J3 series) in new builds and planned upgrades. Key improvements of the MR-J4-11KA over the MR-J3-11KA include: 22-bit encoder resolution versus the MR-J3’s 17-bit (131,072 pulses/rev to 262,144 pulses/rev), Advanced Vibration Suppression Control II versus AVSC I, built-in STO safety function versus external safety contactor, and improved auto-tuning response for faster commissioning. The MR-J4-11KA accepts MR-J3-compatible 17-bit servo motors in a compatibility mode — existing HG-SR, HG-SR (old designation), and HG-JR 11 kW motors from the MR-J3 era can continue operating with the MR-J4-11KA amplifier, enabling phased upgrade where the amplifier is replaced first and the motor is replaced in a subsequent maintenance cycle. For facilities planning complete servo system replacement, upgrading both the MR-J4-11KA amplifier and a compatible HG-UR11K motor simultaneously provides the maximum performance improvement — the 22-bit absolute encoder of the new HG-UR motor provides higher positioning resolution and eliminates the homing requirement at power-up that is required with incremental encoders. For applications currently using the MR-J4-11KA at less than 9 kW average load and considering migration to the SSCNET III/H network platform, the MR-J4-11KB (SSCNET III/H variant) provides the higher-level servo network synchronisation and faster tuning cycle of SSCNET III/H communication while maintaining the same 11 kW power stage.
Frequently Asked Questions
Q: Does the MR-J4-11KA require an external regenerative resistor for all applications, or only for high-regeneration duty cycles?
A: The MR-J4-11KA does not include a built-in regenerative resistor — an external MR-RB series regenerative resistor is always required to handle regenerative braking energy. The MR-RB15 (150 W) is the minimum recommended external resistor for light-duty applications; for high-inertia loads with frequent deceleration cycles (such as CNC machining centre axes with rapid return moves), calculate the average regenerative power using the Mitsubishi servo system sizing tool and select an MR-RB resistor (MR-RB50, MR-RB032, or MR-RB12 as appropriate) with continuous rated power at least 1.5× the calculated average regenerative power.
Q: What circuit protection (fuses or breakers) is recommended for the MR-J4-11KA’s three-phase 200 VAC input?
A: For the MR-J4-11KA at 11 kW output with 200 VAC three-phase supply, the rated input current is approximately 44 A three-phase. Mitsubishi recommends a 60 A three-phase moulded case circuit breaker (MCCB) or an equivalent rated fuse assembly for the MR-J4-11KA’s main circuit power input. A line noise filter (NF series) installed before the MCCB reduces conducted EMI from the amplifier back into the supply network — required for CE marking compliance in European installations and recommended for all industrial panel installations to prevent interference with other equipment on the same supply.
Q: Can the MR-J4-11KA operate in torque control mode for tension control or winding applications?
A: Yes. The MR-J4-11KA supports torque control mode in addition to position and speed control modes. In torque control mode, the analogue torque command input (±10 VDC) sets the commanded motor torque independent of position, enabling the MR-J4-11KA to drive winding, unwinding, and tension control applications where the motor must maintain a constant torque output proportional to the tension command signal. The torque control mode is selected via parameter PR1.01 in MR Configurator2, and the torque command input connects to the CN1 analogue input terminal on the MR-J4-11KA.
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