Motor Coils Information

Motor coilMotor coils are used with motors, generators, stators, and armatures. Many feature Class F or Class H insulation and can be sealed for severe operating conditions. There are many different types of products. Some motor coils are designed for specific types of alternating current (AC) or direct current (DC) motors. 


Product categories include:

  • AC motor coils
  • DC motor coils
  • linear motor coils
  • stepper motor coils
  • servo motor coils

Traditionally, the motor coils that produce the magnetic field are called “field coils” while the coils and the solid core are called the “armature." Generator coils are designed for use with generators, machines that convert mechanical energy into electrical energy. Stator coils are designed for use with a stator, the stationary part of a generator within which a rotor turns. Finally, armature coils are designed for armatures, devices that vibrate under the influence of a magnetic field, or within which an electromotive force is induced. 


Specifications for motor coils vary by motor coil type:

  • Field coils can be flat, layered, random, or edge-style; clockwise or counter-clockwise; and carry specifications such as width, thickness, diameter, and total turn count.
  • Stator coils differ in terms of core bore, core length, and coil support; support ring inner diameter (ID) and support ring outer diameter (OD); and coil length and coil weight.
  • Armature coils carry specifications such as coil span, coil length, and coil diameter; riser width, depth, and distance; minimum and maximum diameters for rear support and front support; and lead materials and lead lengths.
  • Rotor coils differ in terms of number of slots, iron diameter, iron length, number of single coils per slot, turns per coil, wire arrangement per single coil, and wire sizes. 


Motor coils are used in a variety of applications and industries. Field coils are series, compound, shunt, and edgewound coils used with DC motors, synchronous AC motors, and generators. Edgewound coils can range in size from several inches to over 10 feet. Products that weigh thousands of pounds are used in heavy-duty applications such as water wheels. Specialty coils include high-energy, water-cooled coils; blowout, control and relay-signal coils; solenoid, transformer, reactor and choke coils; as well as brake and magnet coils. Some motor coils are foam-encapsulated in their cartons or crates to prevent damage during shipping.

Related Information

CR4 Community—Quick Three-Phase Motor Oil Connection Question

CR4 Community—DC Motor Field Coils Getting Overheated Often

CR4 Community—Turns Per Coil

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Marrrci / CC BY-SA 3.0