How a Single Coil Powers Multiple Motor Armatures Simultaneously

A 1973 design for an electric motor that uses a single central coil to power several separate armatures arranged in a circle.

What it covers

This patent describes a motor assembly where multiple armatures are placed in a circular pattern between two disks. These disks have interlocking finger-like projections that act as magnetic poles. A single central electromagnetic coil sits between the disks, creating a magnetic field that flows through these fingers to drive all the armatures at once. Essentially, it allows one power source to run multiple rotating parts simultaneously within a compact, integrated housing.

What it doesn't cover

• —Does not cover motors using permanent magnets instead of an electromagnetic coil.
• —Does not cover linear motors where the armatures move in a straight line.
• —Does not cover single-armature motors.
• —Does not cover motors where the armatures are not arranged in a circular, parallel array.

The clever bit

The use of interdigitated finger portions creates a shared magnetic flux path, allowing one coil to effectively energize multiple independent armatures without needing individual coils for each one.

Why it matters

This design represents an early attempt at high-density motor packaging. By sharing a single magnetic field source across multiple armatures, it aimed to reduce the weight and complexity of multi-motor systems, which is a common challenge in robotics and automated machinery.

Real-world examples

• 1.Early multi-spindle industrial drills
• 2.Compact automated assembly line actuators