Explained: Mitsubishi Servo Hg Kr73b Standards, Composition, and Industrial Use

Specifications and Materials of the Mitsubishi HG-KR73B Servo Motor

Technical Specifications

Key Mechanical Specifications

The Mitsubishi HG-KR73B servo motor is engineered for precision and durability in industrial automation. With a compact yet robust design, it features a rotor diameter of 173 mm and an overall length of 470 mm, making it suitable for integration into various machinery setups. It delivers a rated torque of 4.1 Nm, with peak performance reaching up to 12 Nm of maximum torque, ensuring reliable operation under dynamic loads.

The motor offers a rated power output of 750 W, scaling up to a maximum power of 2 kW for short bursts, ideal for applications requiring temporary high-load performance. It operates at a rated speed of 3,000 rpm, with a maximum speed capability of 4,000 rpm, providing excellent responsiveness and control. The motor is protected to the IP65 standard, offering full dust protection and resistance to low-pressure water jets from any direction—making it well-suited for harsh industrial environments.

Electrical Specifications

The HG-KR73B supports a wide input voltage range of 100–240 V AC, allowing for global compatibility across different power systems. It operates on a standard frequency of 50/60 Hz and is designed for single-phase power supply, simplifying installation in a wide range of industrial and commercial applications. This flexibility makes it adaptable to diverse electrical infrastructures without requiring additional conversion equipment.

Performance & Feedback Specifications

Precision control is achieved through a high-resolution 20-bit digital encoder, providing 1,000 pulses per revolution (P/R) for accurate position and speed feedback. The internal feedback device ensures real-time monitoring and closed-loop control, essential for applications demanding tight tolerances and repeatability. The servo motor functions reliably within an operating temperature range of -10°C to +60°C, making it suitable for both cold storage facilities and hot manufacturing environments.

Detailed Specifications Table

Specifications	Details
IP Code	IP65 (Dust-tight & protected against water jets)
Dimensions (Diameter × Length)	173 mm × 470 mm
Weight	6.3 kg
Rated Torque	4.1 Nm
Maximum Torque	12 Nm
Rated Current	3.3 A
Maximum Current	8 A
Rated Power	750 W
Maximum Power	2 kW
Power Factor	0.7
Output Frequency	1 – 100 Hz
Servo Voltage	±10 V
Input Voltage & Frequency	100–240 V AC / 50–60 Hz (Single-phase)

Materials and Construction

The Mitsubishi HG-KR73B servo motor is constructed using a combination of high-grade metal, steel, and engineering plastics, ensuring structural integrity, thermal stability, and long-term reliability. Its rugged build allows it to perform efficiently in demanding industrial environments, including manufacturing lines, CNC machines, and robotic systems.

Core Structural Materials

• Steel and Cast Metal Housing: Provides excellent mechanical strength and protects internal components from impact and vibration.
• Engineering Plastics: Used in insulation and non-conductive parts to reduce weight and prevent electrical leakage.
• Commercial-Grade Bearings: Precision-engineered to handle high torque loads and ensure smooth, quiet rotation over extended periods.

Internal & Electrical Components

• Copper Windings: High-purity copper ensures optimal electrical conductivity and minimizes energy loss.
• Aluminum Components: Used for heat dissipation and lightweight structural support.
• Silicon Carbide (SiC): Employed in insulation and semiconductor elements to enhance thermal resistance and electrical isolation.
• Sealing Materials: Rubber and synthetic seals maintain the IP65 rating by preventing ingress of dust and moisture.

Each material is carefully selected to balance performance, durability, and efficiency. The integration of low-friction bearing materials reduces wear and extends service life, while the advanced sealing system ensures consistent performance in dusty or humid conditions. This meticulous material selection contributes to the motor’s reputation for reliability and longevity in continuous-duty applications.

Expert Tip: To maximize the lifespan of the HG-KR73B, ensure proper ventilation and avoid operating near the upper temperature limit (60°C). Regular inspection of seals and connections can prevent premature failure in harsh environments.

Usage and Scenarios: Mitsubishi Servo Motors in Industrial Applications

Mitsubishi servo motors are renowned for their precision, reliability, and high dynamic response, making them ideal for a wide range of automated industrial applications. These advanced motion control systems deliver exceptional performance in environments requiring accuracy, repeatability, and efficiency. From automotive manufacturing to aerospace engineering, Mitsubishi servos enhance automation, reduce cycle times, and improve product quality.

Key Applications Across Industries

Automotive Manufacturing

Mitsubishi servo motors are extensively used in the automobile industry for robotic welding, painting, material handling, and assembly line operations. Their precise torque and speed control enable seamless coordination of robotic arms, ensuring consistent weld quality and accurate part placement.

In vehicle assembly lines, servos power automated guided vehicles (AGVs) and conveyor systems that transport components with millimeter-level accuracy. They also drive testing rigs used to simulate real-world conditions on prototypes, allowing engineers to evaluate performance, durability, and safety compliance under controlled environments.

Robotics and Automation

Robotic systems rely heavily on Mitsubishi servos for joint actuation, end-effector control, and path precision. Whether in pick-and-place machines, palletizing robots, or collaborative robots (cobots), these motors provide smooth, responsive motion essential for high-speed operations.

Their closed-loop feedback system ensures real-time correction of positioning errors, enabling sub-micron accuracy. This level of control is critical in applications such as semiconductor handling, medical device assembly, and electronics manufacturing where even minor deviations can lead to defects.

Conveyor and Material Handling Systems

In modern production facilities, conveyor belts equipped with Mitsubishi servo drives offer synchronized, variable-speed operation. This allows for efficient product transfer between workstations, accumulation zones, and packaging units without bottlenecks.

Servos enable soft start/stop functionality, reducing mechanical stress and wear on belts and rollers. Additionally, they support indexing and positioning tasks—such as aligning parts for inspection or labeling—by precisely controlling belt movement in discrete increments.

Aerospace and Aviation Systems

The aerospace industry utilizes Mitsubishi servo motors in flight control systems, including actuation of flaps, slats, and landing gear mechanisms during ground testing and simulation. Their ability to maintain stable operation under varying loads and temperatures makes them suitable for rigorous testing environments.

On the production side, servos are employed in automated drilling, riveting, and composite layup machines used in aircraft fuselage and wing assembly. These applications demand extreme positional accuracy and synchronization across multiple axes, which Mitsubishi servos deliver through integrated encoder feedback and advanced tuning algorithms.

Industry	Application	Benefits of Mitsubishi Servo Motors
Automotive	Robotic Assembly, Prototype Testing	High repeatability, fast response, improved throughput
Electronics	Circuit Board Handling, SMT Machines	Precision positioning, low vibration, compact design
Pharmaceuticals	Labeling, Filling, Packaging Lines	Hygienic compatibility, smooth motion, easy integration
Metalworking	CNC Machines, Press Brakes	High torque density, excellent speed control, durability

Step-by-Step Setup Guide

Proper installation of a Mitsubishi servo motor is crucial for achieving optimal performance and longevity. Follow these best practices to ensure a safe and effective setup:

Review Manufacturer Documentation: Always begin by consulting the official user manual and technical datasheets. These documents contain critical information about torque ratings, wiring diagrams, encoder types, and environmental requirements.

Prepare the Mounting Surface: Ensure the mounting base is clean, flat, and rigid. Any misalignment or flexing can cause vibration, premature bearing wear, and reduced accuracy.

Secure the Motor: Use recommended torque specifications when tightening mounting bolts. Over-tightening can damage the housing, while under-tightening may lead to shifting during operation.

Connect to the Servo Drive: Before making electrical connections, confirm that the power is OFF. Match wire color codes and terminal labels (e.g., U/V/W for motor phases, PE for ground) precisely. Use shielded cables for encoder and power lines to minimize electromagnetic interference (EMI).

Seal Unused Ports: Install sealing plugs on any open cable entries to protect internal components from dust, moisture, and contaminants—especially important in harsh industrial environments.

Perform Pre-Operation Checks: Inspect all connections, verify grounding, and manually rotate the shaft to ensure smooth movement. Use diagnostic tools (like Mitsubishi’s MR Configurator2) to confirm communication between the controller and drive.

Conduct a Test Run: Power up the system and perform a low-speed jog test. Monitor for unusual noise, overheating, or erratic motion. Adjust gain parameters and inertia ratios as needed using auto-tuning functions for optimal responsiveness.

Maintenance and Replacement Procedures

Regular maintenance extends the life of Mitsubishi servo motors and prevents unplanned downtime. A proactive approach ensures consistent performance and early detection of potential failures.

Visual Inspections: Conduct routine checks for signs of physical damage, oil leaks, corrosion, or loose fasteners. Pay special attention to seals and connectors, which are vulnerable to environmental degradation.

Cleaning Protocol: Wipe down the motor housing with a slightly damp cloth to remove dust and debris. Avoid high-pressure water or solvents that could penetrate seals and damage internal components.

Lubrication Management: While most modern servo motors use sealed bearings, some models may require periodic lubrication. Always follow the manufacturer’s schedule and use specified grease types to prevent contamination.

Electrical Integrity Checks: Test cable insulation resistance and check for loose terminals or cracked wires. High temperatures can degrade insulation over time, increasing the risk of short circuits or ground faults.

Thermal Monitoring: Use infrared thermography or built-in temperature sensors to detect abnormal heating, which may indicate overload, poor ventilation, or failing components.

Replacement Process: When a servo motor reaches end-of-life or suffers irreparable damage, replace it with an OEM-compatible unit. After mechanical installation, reconfigure the drive settings—including inertia ratio, pole count, and encoder resolution—to match the new motor’s specifications. Recalibrate the system to maintain process accuracy.

Important: Never bypass safety interlocks or operate a servo system without proper grounding and protective enclosures. Improper setup or maintenance can result in equipment damage, fire hazards, or personal injury. Always de-energize the system before performing any service work, and follow lockout/tagout (LOTO) procedures in industrial settings.

Quality and Safety Considerations for Mitsubishi Servo Motors

Ensuring high quality and operational safety in Mitsubishi servo motors is essential for maximizing performance, extending equipment lifespan, and protecting personnel. These factors directly influence system reliability, efficiency, and compliance with industrial safety standards. Below is a comprehensive guide to the key quality and safety aspects you should consider when selecting, operating, and maintaining Mitsubishi servo motors.

Quality Considerations

The performance and longevity of a Mitsubishi servo motor are determined by several critical quality factors. These elements ensure precision control, consistent operation, and resistance to environmental stressors.

• Rated and Maximum Torque: These specifications define the motor’s load-handling capability. The rated torque indicates continuous operational capacity, while maximum torque reflects short-term peak performance under stress. Selecting a motor with appropriate torque ratings ensures smooth motion control and prevents premature wear.
• IP (Ingress Protection) Rating: Mitsubishi servo motors feature IP ratings that specify protection against dust and moisture. Higher IP ratings (e.g., IP65 or IP67) indicate superior sealing, making the motor suitable for harsh environments such as wet, dusty, or outdoor applications.
• Electrical Isolation: Proper insulation of internal windings and components prevents electrical leakage, short circuits, and damage from voltage spikes. High-quality isolation enhances safety and ensures stable performance in variable power conditions.
• Thermal Management: Ambient and operational temperatures significantly affect motor efficiency. Operating within the manufacturer-specified temperature range prevents overheating, insulation breakdown, and demagnetization of internal components.
• Build Consistency and Materials: Precision manufacturing using high-grade materials ensures dimensional accuracy, reduced vibration, and long-term reliability. Genuine Mitsubishi components undergo rigorous testing to meet global quality standards.

Pro Tip: Always source genuine Mitsubishi servo motors from authorized distributors to ensure authenticity, full technical support, and warranty coverage.

Safety Considerations

Safety in servo motor operation involves both preventive maintenance and adherence to safe work practices. Mitsubishi designs its servo systems with built-in safety features, but proper handling remains crucial.

• Workspace Safety: Keep the motor’s environment clean and free of debris, metal shavings, or flammable materials. Clutter can obstruct ventilation, cause overheating, or lead to mechanical failure and fire hazards.
• Pre-Operation Inspections: Regularly inspect seals, bearings, connectors, and shafts for wear, corrosion, or misalignment. Damaged components can lead to catastrophic failure or unsafe operating conditions.
• Lockout/Tagout (LOTO) Procedures: Always disconnect and lock out power before performing maintenance. Servo motors can generate back-EMF or unexpected movement even when powered down, posing serious injury risks.
• Avoid Contact During Operation: Never touch the motor, shaft, or coupling while the system is running. Surface temperatures can exceed safe limits, and rotating parts present entanglement hazards.
• Electrical Safety: Exposed or frayed wires pose severe electrocution risks. Ensure all wiring is properly insulated, secured, and grounded. Use personal protective equipment (PPE) when working near live circuits.
• Proper Grounding: Always ground the motor frame and drive system to prevent static buildup and protect against electrical faults. Improper grounding can damage sensitive electronics and endanger personnel.

Critical Reminder: Never bypass safety interlocks or emergency stops—even during testing. These systems are designed to prevent injury and equipment damage.

Professional Recommendation: Implement a preventive maintenance schedule that includes torque checks, thermal imaging, vibration analysis, and insulation resistance testing. Early detection of issues such as bearing wear or winding degradation can prevent unplanned downtime and costly repairs. Additionally, train personnel on Mitsubishi’s safety guidelines and emergency response protocols to foster a culture of safety in your facility.

Quality Factor	Description	Recommended Standard	Inspection Frequency
IP Rating	Protection against dust and moisture ingress	IP65 or higher for industrial environments	Monthly visual check
Thermal Performance	Operating temperature within safe limits	Below 80°C ambient + motor rise	Weekly monitoring
Electrical Insulation	Resistance to current leakage and short circuits	≥100 MΩ at 500V DC	Quarterly with megohmmeter
Mechanical Integrity	Condition of bearings, shaft, and coupling	No play, noise, or visible wear	Bi-weekly inspection
Connection Security	Tightness and corrosion of terminals and cables	Firm, clean, and properly torqued	Monthly

Additional Best Practices

• Use Genuine Spare Parts: Aftermarket or counterfeit components may not meet Mitsubishi’s engineering tolerances, leading to inefficiency or failure.
• Follow Manufacturer Guidelines: Adhere to installation, wiring, and commissioning instructions in the official technical manual.
• Environmental Control: Install motors in areas with stable temperature, low humidity, and minimal chemical exposure when possible.
• Vibration Monitoring: Excessive vibration indicates misalignment or imbalance—address immediately to prevent damage.
• Documentation: Maintain logs of inspections, replacements, and performance data for traceability and predictive maintenance.

Servo Motor Selection and Operational Guidelines

This comprehensive guide provides essential information for selecting and operating Mitsubishi servo motors effectively. Whether you're integrating a servo into an industrial automation system or maintaining existing equipment, understanding environmental requirements and selection criteria is crucial for maximizing performance, longevity, and safety.

Important Note: Servo motors are precision industrial components. Improper installation or operation outside recommended conditions can lead to premature failure, reduced efficiency, or safety hazards. Always consult the manufacturer's technical manual before deployment.

Optimal Operating Environment for Servo Motors

Mitsubishi servo motors are engineered for robust industrial performance but require specific environmental conditions to operate at peak efficiency. Below are key factors to consider when installing and operating these systems.

• Work Environment

  Mitsubishi servo motors are designed to function reliably in demanding industrial environments, including those with temperature extremes. However, for optimal performance and longevity, they should be operated in a clean, cool, and dry space. Exposure to excessive dust, dirt, or humidity can compromise internal components, reduce cooling efficiency, and accelerate wear—potentially shortening the motor’s operational life. Consider installing protective enclosures or filtration systems in particularly harsh environments.

• Work Area and Altitude

  The servo motor is rated for reliable operation up to 1,000 meters (3,280 feet) above sea level. Beyond this altitude, reduced air density can impair the motor’s self-cooling capabilities. Proper ventilation is critical—stagnant or recirculated air restricts heat dissipation, leading to overheating and thermal shutdown. Ensure adequate airflow around the motor housing and avoid enclosing it in tight, unventilated spaces.

• Usage Frequency and Temperature Limits

  While the servo motor features self-cooling mechanisms and is suitable for continuous operation, it should not be exposed to ambient temperatures exceeding 40°C (104°F). Prolonged exposure to high heat degrades insulation and electronic components. With proper maintenance—including regular cleaning, lubrication (if applicable), and inspection—the motor can exceed its base life expectancy of approximately 20,000 hours. Scheduled maintenance is a key factor in extending service life and preventing unplanned downtime.

• Noise Level and Installation Location

  During operation, the servo motor generates noise levels exceeding 70 dB, comparable to the sound of a vacuum cleaner or busy street traffic. This level of noise can be disruptive in quiet environments. As such, these motors are not recommended for residential areas or noise-sensitive facilities without appropriate sound-dampening measures. Consider acoustic enclosures or remote mounting in high-noise applications.

Key Criteria for Selecting the Right Servo Motor

Selecting the appropriate servo motor involves matching technical specifications to your application’s mechanical and control requirements. Below are critical selection factors to ensure optimal performance and energy efficiency.

• Torque Requirement

  Choose a servo motor with sufficient torque to handle both the peak and continuous loads of your application. Undersized motors will struggle under load, leading to overheating, stalling, or mechanical damage ("servo beating"). Oversized motors consume excess energy and increase costs. Use dynamic load calculations to determine the exact torque needed, including acceleration, friction, and inertia factors.

• Speed Capability

  The motor’s maximum rotational speed under load is a vital specification. Ensure the selected servo can achieve speeds higher than your application’s average operating range to allow for acceleration headroom and maintain responsiveness. Consider the relationship between speed and torque (torque curve), as available torque typically decreases at higher RPMs.

• Control Type

  Servo motors support various control modes: position, velocity (speed), and torque control. Choose the mode that aligns with your application—e.g., position control for CNC machines, torque control for tensioning systems. For maximum precision and responsiveness, opt for electronic control systems over mechanical ones, as they offer tighter feedback integration and faster correction loops.

• Power Source Compatibility

  Mitsubishi servos typically operate on AC or DC power supplies. Select a motor that matches your facility’s power infrastructure and voltage standards. The power source directly influences performance, efficiency, and compatibility with drives and controllers. Verify input voltage, frequency, and phase requirements before installation.

• Feedback System

  Feedback is essential for closed-loop control, enabling the servo to adjust its output based on real-time performance data. Common feedback devices include optical encoders (high precision) and potentiometers (cost-effective for basic applications). Encoders provide accurate position, speed, and direction data to the control system, ensuring precise motion control and error correction. Choose a feedback type that meets your accuracy and resolution requirements.

Selection Factor	Recommended Practice	Risks of Poor Selection	Verification Tools
Torque	Select 10–20% above peak load requirement	Overheating, stalling, mechanical stress	Torque calculator, load analysis software
Speed	Ensure max speed exceeds operational needs by 15%	Limited acceleration, poor response	RPM meter, motion simulation tools
Control Type	Match to application: position, speed, or torque	Inaccurate movement, instability	Controller compatibility charts
Power Source	Verify voltage, phase, and frequency match	Motor damage, inefficient operation	Multimeter, power quality analyzer
Feedback	Use encoders for high-precision applications	Position drift, reduced accuracy	Oscilloscope, encoder tester

Expert Tip: When integrating a new servo motor, perform a test run under simulated load conditions before full deployment. Monitor temperature, noise, and response accuracy to verify proper selection and installation. This proactive step can prevent costly errors and ensure seamless integration into your system.

Final Recommendations

• Always refer to the official Mitsubishi servo motor technical manual for model-specific specifications and installation procedures.
• Consider environmental protection accessories such as dust covers, cooling fans, or sealed enclosures for challenging installations.
• Implement a preventive maintenance schedule to inspect connections, clean vents, and verify feedback signal integrity.
• Train personnel on safe handling and emergency shutdown procedures for servo-driven systems.
• Partner with certified automation specialists when upgrading or retrofitting servo systems to ensure compatibility and optimal performance.

By carefully considering both operational environment and selection criteria, you can ensure reliable, efficient, and long-lasting performance from your Mitsubishi servo motor system. Proper selection and maintenance not only enhance productivity but also contribute to workplace safety and reduced lifecycle costs.

Frequently Asked Questions About Mitsubishi Servo Motors

Q1: What are the signs that a Mitsubishi servo motor needs replacement?

Recognizing early warning signs can prevent unexpected downtime and costly repairs. Key indicators that your Mitsubishi servo motor may need replacing include:

• Overheating: Excessive heat generation during normal operation, often accompanied by thermal shutdowns or error codes on the drive system.
• Unusual Noises: Grinding, buzzing, or screeching sounds that suggest bearing wear, rotor imbalance, or internal mechanical failure.
• Performance Degradation: Inconsistent speed control, reduced torque output, or difficulty maintaining positioning accuracy.
• Internal Wear: Visible signs of wear in components such as brushes (in brushed models), shafts, or gears—especially after inspection or maintenance.
• Frequent Alarms: Repeated fault messages from the controller related to overcurrent, encoder errors, or phase imbalance.

If multiple symptoms appear together, it’s advisable to conduct a professional diagnostic test or consider replacement to avoid system failure.

Q2: How should one maintain a Mitsubishi servo motor?

Proper maintenance extends the life of your servo motor and ensures optimal performance. Follow these best practices for routine care:

• Regular Cleaning: Clean the motor housing and ventilation areas at least once per week using compressed air or a soft brush to remove dust, debris, and metal particles that can cause overheating.
• Lubrication: Lubricate moving parts (such as couplings or gearboxes, if applicable) according to the manufacturer’s schedule. Avoid over-lubrication, which can attract contaminants.
• Seal Inspection: Check motor seals and gaskets regularly for cracks, warping, or compression loss—especially in harsh environments—to prevent moisture or contaminant ingress.
• Electrical Connections: Inspect all wiring, connectors, and terminals for looseness, corrosion, or insulation damage. Tighten connections and replace frayed wires promptly to prevent arcing or signal loss.
• Vibration Monitoring: Use vibration analysis tools periodically to detect early signs of bearing wear or misalignment.

Adhering to a preventive maintenance schedule can significantly reduce unplanned outages and improve system reliability.

Q3: Is the Mitsubishi servo motor suitable for outdoor use?

Mitsubishi servo motors are primarily designed for indoor industrial environments, but they can be used outdoors with appropriate precautions:

• Environmental Vulnerabilities: Exposure to rain, snow, high humidity, and temperature extremes can damage internal electronics, cause rust, and degrade insulation.
• Protection Measures: When installing outdoors, enclose the motor in a weatherproof cabinet or housing with proper NEMA or IP-rated protection (e.g., IP65 or higher for dust and water resistance).
• Thermal Management: Ensure adequate ventilation or use cooling fans/heaters to prevent condensation and maintain operating temperature ranges.
• Mounting Location: Position the motor under shelter or cover to minimize direct exposure to sunlight and precipitation.

With proper environmental safeguards, Mitsubishi servos can operate reliably in outdoor applications such as construction equipment, agricultural machinery, or automated gates.

Q4: How long can a Mitsubishi servo motor last with proper maintenance?

With diligent care, a Mitsubishi servo motor typically has an operational lifespan of approximately 20,000 hours. However, actual longevity depends on several factors:

Factor	Impact on Lifespan
Operating Environment	Clean, dry, and temperature-controlled settings extend life; dusty, humid, or corrosive conditions shorten it.
Usage Frequency	Continuous high-load operation reduces lifespan compared to intermittent or light-duty cycles.
Maintenance Routine	Regular cleaning, lubrication, and inspections can add thousands of hours to motor life.
Power Supply Stability	Stable voltage and proper grounding prevent electrical stress and insulation breakdown.

Some well-maintained units have been known to exceed 30,000 hours, especially in controlled automation systems. Monitoring performance trends helps predict end-of-life more accurately.

Q5: What are the most common signs of damage to servomotor wires?

Damaged wiring poses serious risks to both equipment and personnel. Watch for these telltale signs of wire degradation:

• Visible Damage: Frayed, cracked, or exposed conductors indicate physical wear, often caused by bending, abrasion, or rodent activity.
• Sparking or Arcing: Visible sparks near connectors or along the cable run suggest insulation failure or loose connections.
• Electrical Shocks: Tingling sensations when touching the motor frame or cables may indicate grounding issues or insulation breakdown.
• Power Fluctuations: Intermittent operation, signal noise, or erratic motor behavior can stem from poor conductivity due to damaged wires.
• Burn Marks or Melting: Discoloration or softening of insulation points to overheating from overload or short circuits.

Safety Note: Exposed or damaged wires are a major safety hazard and must be repaired or replaced immediately. Always de-energize the system before inspection and use conduit, cable carriers, or shielding to protect wires in dynamic or industrial environments.