A 5-Step Guide to Selecting an ML Coupling

Step 1: Determine Torque & Select Size
This is the most critical step to prevent under-sizing (failure) or over-sizing (costly and inefficient).

• Calculate Required Torque: Determine the operational torque of your application using motor power (kW or HP) and speed (RPM).

• Apply a Service Factor: Multiply your calculated torque by a service factor based on the driven equipment’s operational harshness.

  • *Examples: Centrifugal Pumps (1.5-2.0), Conveyors (1.5-2.0), Compressors (2.0-3.0).*

• Match to ML Size: Select an ML coupling size (e.g., ML48, ML68, ML98) where the coupling’s Rated Torque is higher than your calculated torque (with service factor). Consult the manufacturer’s torque table.

Step 2: Define Shaft & Speed Requirements

• Shaft Diameters & Keyways: Accurately measure the diameters of both the motor and driven machine shafts. ML couplings typically have parallel bores with keyways. Ensure the chosen size can accommodate your shaft diameters.

• Maximum RPM: Confirm your system’s maximum operating speed is below the coupling’s maximum speed rating.

Step 3: Assess Misalignment & Environment

• Misalignment Capacity: ML couplings are excellent for moderate angular and parallel misalignment. Check the manufacturer’s specifications for the exact limits for your chosen size and do not exceed them.

• Environmental Conditions:

  • Temperature: Standard NBR (Nitrile) spiders work in a range of approx. -30°C to +80°C. For higher temperatures or outdoor use, materials like EPDM or Hytrel may be required.

  • Oils & Chemicals: Exposure to lubricants or solvents can degrade standard rubber. Choose a spider material (e.g., Polyurethane) with appropriate chemical resistance if needed.

Step 4: Select the Correct Spider Hardness
The elastic spider is the heart of the coupling. Its hardness (Shore A) directly impacts performance:

• Standard (e.g., Shore 92A): Good all-around performance for general applications.

• Softer (e.g., Shore 80A): Provides superior vibration damping and shock absorption for high-impact applications.

• Harder (e.g., Shore 95A): Offers higher torsional stiffness for more precise applications.

Step 5: Finalize with a Trusted Supplier
Choose a supplier who provides:

• Accurate Technical Data: Clear torque, speed, and misalignment tables.

• Customization (OEM/ODM): Ability to provide non-standard bores or special spiders.

• Proven Quality: ISO 9001 certification is a good indicator of reliable quality control.

Summary: Why Choose an ML Coupling?

Choose an ML Coupling with an Elastic Spider if your application requires:

• Excellent Vibration Damping and shock absorption.

• Electrical Insulation between shafts.

• Moderate Compensation for misalignment.

• Maintenance-Free operation (no lubrication required).

• A Cost-Effective and reliable solution for pumps, compressors, fans, and conveyors.

Final Recommendation: Always consult the manufacturer’s technical catalog for precise sizing. For complex applications with high shock loads or specific environmental challenges, provide your parameters to the supplier for a verified selection.