Polynoids – AC Linear Induction Actuators

Overview

Polynoids are electrically operated, open-loop AC linear induction actuators that deliver constant force across their entire stroke. Operating directly from 115/230 VAC line voltage or with adjustable frequency drives, these actuators provide a cost-effective, low-maintenance alternative to pneumatic cylinders.

The system consists of two components: a copper-clad steel rod with threaded mounting holes and a stator assembly with interconnected coils housed in a toothed steel structure. Direction reversal is accomplished by switching two of three leads. Optional holding coils enable end positioning at one or both ends.

How Polynoids Work

Polynoids operate on AC linear induction principles, creating linear motion through electromagnetic interaction between the stator and rod. When AC voltage energizes the stator coils, a traveling magnetic field is generated within the toothed steel assembly.

The copper-clad steel rod acts as a secondary element. As the traveling magnetic field passes along the stator, it induces eddy currents in the copper cladding, creating an opposing magnetic field. The interaction between these fields produces thrust, propelling the rod linearly through the stator.

Speed is controlled by input frequency – either fixed with direct AC line voltage or variable with an adjustable frequency drive. Integral rulon bearings maintain proper alignment and clearance between components. Force remains constant throughout the stroke, limited only by the rod’s end stops.

Key Components

Stator Assembly

Series of interconnected coils housed in toothed steel laminations. Two configurations available:

Finned Series: Enhanced heat dissipation for improved thermal performance in demanding applications

Smooth Series: Compact design for space-constrained installations

Optional holding coils provide electromagnetic braking at one or both ends for precise end positioning.

Rod

Custom copper-clad steel shaft available in any length with tapped mounting holes for easy integration. Standard lengths from 4″ to 72″ [101.6mm to 1828.8mm].

Performance Specifications

Force Output: Up to 445 N [100 lbs]

Speed: Up to 2.3 m/s [90 in/sec]

Acceleration: Up to 9.8 m/s² [1g]

Power: Single or 3-phase AC line voltage, 50 or 60 Hz

Stroke: Unlimited – determined by rod length and end stops

Configurations: 2, 3, 4, 6, 8, 9, 12, or 24 coil assemblies

Bearings: Integral rulon bearings for maintenance-free operation

Note: Single-phase operation requires external capacitor (capacitor selection chart provided)

Advantages & Limitations

Control Options

Single-Phase AC: Direct connection to 115/230 VAC with external capacitor (C1-C10 ratings provided)

Three-Phase AC: Direct connection to line voltage, no capacitor required

Variable Speed: Adjustable frequency drive for precise speed control and dynamic operation

Holding Coil Option: Built-in electronic brake with bridge rectifier diode for end holding

Configuration Options

• Finned or smooth stator housings
• 2 to 24 coil configurations for force scaling
• Custom rod lengths from 4″ to 72″+ [101.6mm to 1828.8mm+]
• Single or dual holding coils for end positioning
• Single-phase (115/230 VAC) or three-phase operation

Applications

Polynoids excel as electric replacements for pneumatic cylinders in industrial automation and material handling:

Industrial Automation:

• Electrical switchgear actuation
• Conveyor belt product diverters
• Gate and door actuators
• Positioning systems

Material Handling:

• Sorting equipment
• Product routing mechanisms
• Transfer systems
• Indexing operations

Manufacturing:

• Assembly line automation
• Pick-and-place operations
• Part ejection systems
• Process automation

Why Choose Polynoids

Polynoids offer a maintenance-free alternative to air cylinders with electric precision and reliability. Operating directly from AC line voltage eliminates expensive controllers while delivering constant force across unlimited strokes. Integral rulon bearings ensure long life without lubrication. Simple two-component design reduces complexity, and reversible operation with optional holding coils provides flexible end positioning for switchgear, conveyors, and industrial automation applications.

Ordering Information

Available in 2, 3, 4, 6, 8, 9, 12, and 24 coil configurations. Custom rod lengths supplied to specification. Finned or smooth stator housings. Optional holding coils and required capacitors for single-phase operation available.