The MR-J4-22KA is Mitsubishi Electric’s 22 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 110 A for Mitsubishi HG-UR and HG-JR series ultra-high-power servo motors — the maximum single-unit continuous output power available in the MR-J4-A 200 V pulse train input series, designed for the most power-demanding single-axis servo applications including large horizontal machining centre spindle drives, heavy-load industrial robot trunk axes, and large-scale automated guided vehicle (AGV) drive systems where 22 kW of continuous servo power represents the practical limit of a single amplifier unit. Atlantech Drives holds stock of the MR-J4-22KA. Contact us for fast worldwide delivery and competitive pricing.
What Is the MR-J4-22KA?
The MR-J4-22KA is a MELSERVO-J4 series servo amplifier providing 22 kW (22,000 W) continuous output power — the absolute maximum continuous rated power available from a single MR-J4-A 200 V amplifier — for Mitsubishi servo motors in the HG-UR22K, HG-JR22K2, and equivalent 22 kW servo motor models. At 110 A continuous output current, the MR-J4-22KA’s power stage represents the upper limit of IGBT module current rating practical in a single servo amplifier chassis without entering common bus multi-axis drive territory. The amplifier requires three-phase 200–240 VAC supply with input current of approximately 90 A per phase at full 22 kW load — requiring appropriately rated three-phase circuit protection (typically 125 A MCCB), heavy-gauge three-phase input cabling (35 mm² minimum), and a power supply panel infrastructure rated for the input current. The MR-J4-22KA includes all standard MR-J4 servo control features including 22-bit multi-turn absolute encoder support, Advanced Vibration Suppression Control II with automated machine resonance detection and notch filter configuration, dual-channel STO safety function compliant with IEC 61800-5-2 SIL2 and EN ISO 13849-1 PLe, and MR Configurator2 USB and RS-422 connectivity for complete commissioning and diagnostic access.
Key Technical Specifications
- Model: MR-J4-22KA
- Rated Output Power: 22 kW (22,000 W)
- Power Supply: 200–240 VAC three-phase only, 50/60 Hz
- Continuous Output Current: 110.0 A
- Maximum Output Current: 330.0 A (3× continuous peak)
- Compatible Servo Motors: HG-UR22K, HG-JR22K2, HG-UR22K4 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 SIL2, EN ISO 13849-1 PLe
- Regenerative Brake: External MR-RB series resistor required
- Communication: USB (MR Configurator2), RS-422 (multi-axis cascade)
- Operating Temperature: 0°C to 55°C (forced air cooling)
- Dimensions (W × H × D): 260 mm × 430 mm × 280 mm
- Weight: Approx. 14.0 kg
Typical Industrial Applications
The MR-J4-22KA is specified for the highest continuous power single-axis servo applications where 22 kW of sustained output is required throughout the machine’s operating duty cycle. In large horizontal boring and milling machines with table diameters above 1,200 mm, the MR-J4-22KA drives the spindle motor providing the cutting power for heavy face milling, boring, and deep-hole drilling operations in cast iron and steel at rates that consume the full 22 kW motor capability. Large-format plasma and waterjet cutting gantry systems where the combined cutting head mass and water pressure reaction force requires sustained high servo power specify the MR-J4-22KA for the transverse beam drive axis. In heavy-load industrial robots of the 1,000 kg and above payload class (such as automotive body panel press loading robots), the MR-J4-22KA drives the base rotation axis which must accelerate the robot’s full arm-plus-payload inertia from rest — the 3× peak torque capability (330 A instantaneous) provides the rapid acceleration torque while the 110 A continuous rating handles the sustained holding torque during welding or assembly operations. Ship section automated welding gantries, which traverse heavy welding carriages across large structural sections at precise speeds, use the MR-J4-22KA for the longitudinal traverse axis where the carriage mass and friction demand sustained high servo power at the required welding speeds. Large-format stone and glass cutting bridge saws specify the MR-J4-22KA for the bridge traverse motor where the combined bridge structure mass, cutting force, and water-lubricated friction demand more than 15 kW of sustained servo power.
Troubleshooting Guide
At 22 kW, the MR-J4-22KA is operating at the upper limit of single-unit servo amplifier power — thermal management, power supply quality, and regenerative energy handling are the three most common sources of operational problems at this power level. For AL.50 (overload) alarms occurring during normal operation rather than at peak load, verify the amplifier’s operating temperature using MR Configurator2’s diagnostic monitor — the amplifier’s internal temperature sensor reading should remain below 55°C during continuous full-load operation. If the temperature exceeds 55°C, the cooling fan may be degraded or the panel ventilation is insufficient. For AL.30 (regenerative overvoltage) alarms during motor deceleration, the external regenerative resistor is insufficient for the application’s braking energy — calculate the actual average regenerative power from MR Configurator2’s waveform monitor during a representative deceleration cycle and verify it is within the connected MR-RB resistor’s continuous power rating. A single oversized resistor with inadequate continuous power rating can sustain multiple deceleration cycles before the alarm triggers, making the fault appear intermittent. For AL.10 (undervoltage) alarms occurring under heavy load, check the three-phase supply voltage at the MR-J4-22KA input terminals during full motor acceleration — a 22 kW amplifier drawing 90+ A peak input current causes a supply voltage sag on inadequately rated supply infrastructure. The supply voltage at the amplifier terminals must remain above 170 VAC during peak load conditions; voltages below 170 VAC trigger the undervoltage alarm even if the no-load supply voltage is within specification.
Frequently Asked Questions
Q: Is the MR-J4-22KA the maximum power available in the MR-J4-A pulse train series at 200 V?
A: Yes. The MR-J4-22KA is the highest continuous power model in the MR-J4-A 200 V pulse train input series. For servo applications requiring more than 22 kW from a single axis at 200 V, the next approach is either the MR-J4W series common bus multi-axis amplifier system (which allows multiple axes to share a common DC bus with a power supply unit sized for the combined load) or a 400 V class servo system using the MR-J4-500A4 through MR-J4-22KA4 variants (400 V three-phase supply, allowing higher power at lower current for the same motor output). The 400 V variants provide equivalent servo performance at lower input current, reducing wiring cross-section and circuit protection ratings.
Q: What is the recommended installation approach for the MR-J4-22KA’s external regenerative resistor given its high regenerative energy at 22 kW?
A: The MR-J4-22KA should be matched with the MR-RB50 (500 W) or MR-RB32 (300 W) external regenerative resistor depending on the calculated average regenerative power for the specific application. The regenerative resistor must be mounted with adequate clearance from heat-sensitive components — at 500 W continuous dissipation, the MR-RB50 generates significant local heat and should be mounted on a separate heat-resistant surface (metal panel or heat shield bracket) with at least 100 mm clearance on all sides. Install a thermal overload relay in series with the regenerative resistor’s connection to the MR-J4-22KA as a secondary protection against resistor overheating in the event of regenerative resistor sizing error or unexpected changes in the application’s motion profile.
Q: Can the MR-J4-22KA be commissioned without load connected to verify basic amplifier function?
A: Yes, but with important precautions. The MR-J4-22KA can be powered up and connected to MR Configurator2 for parameter verification without a servo motor connected — the amplifier will display a motor disconnection alarm (AL.16 or equivalent) if no motor encoder is detected, but the alarm can be cleared and basic parameter settings verified. For test operation with the motor connected but without mechanical load, use the servo-on command via MR Configurator2’s JOG operation function at low speed and verify basic encoder feedback and servo response before connecting the mechanical load. Never perform auto-tuning or high-speed test moves without confirming that the mechanical system is fully assembled and the motion envelope is clear of obstructions.
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