Considerations for Selecting a Push-Pull Solenoid

Push-pull solenoids are non-standard components with variable coil parameters. Selecting the appropriate solenoid requires careful evaluation of user-specific requirements to ensure optimal performance. Incorrect coil parameter selection can lead to overheating and potential coil burnout.

Key Factors for Selecting a Push-Pull Solenoid

  1. Size Constraints
    The solenoid’s dimensions directly impact its travel distance and push-pull force. Larger solenoids generally provide greater force and travel capacity. Two common structural types are box-type and tube-type solenoids.

  2. Energization Rate (ED)
    The energization rate (ED) is the ratio of energized time to the total cycle time and is calculated as:

    ED (%) = (Energized Time) / (Energized Time + Off Time) × 100%

    Example: A solenoid energized for 1 second and off for 9 seconds results in:
    ED = (1 / (1 + 9)) × 100% = 10%

    If the actual ED exceeds the coil’s design limit, the coil temperature may rise beyond the insulation threshold, shortening its lifespan and potentially causing failure.

  3. Required Stroke Length
    The solenoid’s moving core travels inward during operation, producing a pulling motion. If a pushing motion is needed, a push rod can be attached to the opposite end of the core.

  4. Required Force (Travel Force, F)
    Force varies throughout the stroke. Generally, longer strokes result in lower force, while shorter strokes yield greater force. The required force must be specified in relation to the stroke length.

  5. Structural Components
    Essential components include:

    • Magnetizing shell

    • Coil skeleton

    • Coil

    • Moving iron core

    • Fixed iron core

    Additional components may include:

    • Push rod – For push-type applications or limiting core movement

    • Spring – For resetting the core; special designs may allow the spring to push loads

    • Terminals, silencing pads, and other accessories – Depending on specific application needs

By carefully defining these parameters, users can select a push-pull solenoid that meets their operational requirements while ensuring safety and longevity.