DC Motors

Direct from Round Rock, Texas

TECO-Westinghouse Motor Company Direct Current (DC) motors are ideally suited to a multitude of industrial and marine applications in which high torque and variable speeds are required. These applications include ship propulsion, mine hoists and steel rolling mills. They also drive many other types of industrial equipment such as fan drives, Banbury mixers and extruders.

To meet the needs of a broad range of applications, our rugged DC motors are available in sizes ranging from 22-inch to 12-foot armature diameters, with available power ratings from 250 hp to over 35,000 hp.

Quality Features / Time-Tested Performance

  • High efficiency designs reduce life cycle costs.
  • Advanced insulation systems protect against moisture, dust, heat, and contamination.
  • Critical area electrostatic coating provides long creepage paths.
  • High temperature rise capabilities offer cost economies.
  • V-ring, "balanced-spring", commutator ensures concentricity and prevents distortion.
  • High fatigue strength risers increase reliability.
  • Lift-away end covers improve accessibility.
  • Ruggedly built spiders smoothly transmit torque.
  • Integral ventilation package available to continuously circulate cooling air.
  • Keyless coupling eliminate inherent disadvantages of key ways.
  • Rigid-support, accurately machined bedplates ensure stability.
  • Armature wedges and banding assure excellent coil ventilation & accessibility.
  • Heavy-duty stators offer outstanding reliability.
  • Bearings with self-aligning, spherical seats provide excellent heat transfer.
  • Rear mounted cross connections provide accessibility and mechanical stability.
  • Full laminated coils reduce eddy current loss.
  • Removable shafts available for both continuous and rapid reversing operation.
  • Wound-on-pole shunt fields assure excellent heat transfer.
  • Sturdy frames provide optimum flux carrying configurations.
  • Rear to front ventilation system provides maximum heat dissipation.



Rolling Mill Motors
Used in the steel and aluminum industries, rolling mill motors generally operate at low speeds and are designed for constant torque with a speed range of up to four to one. Some applications include continuous cold mills, continuous hot strip mills, and reversing hot mills.

Mine Hoists
This equipment transfers products and people from deep mines to the surface. Mine hoists can be overhung from the hoist drum or fitted with supporting bearings.

Industrial Duty Motors
Typically used for fan drives, Banbury mixers, extruders and other applications that require either torque or speed variability.

Special Applications
These include balance machine drives, human centrifuge drives, dynamometers or any application requiring high-torque, fast acceleration and low or variable speed.

Ship Propulsion
The demanding applications for TECO-Westinghouse Motor Company DC propulsion motors and generators include ice breakers, submarines, tugboats, mine sweepers, seagoing dredges, and oceanographic vessels. Three classes of marine propulsion motors are offered. Our class one motors have unique, heavy-duty features and provide special super-quiet operation. These have been produced for use on U.S. Navy vessels.

They can be furnished with adjustable frequency drives (PWM, LCI, and Cyclo-converter) for soft starters or speed regulation.

With all of the advancements made in adjustable frequency drive technology, the variable speed synchronous motor is a logical choice for applications requiring high torque at low speed with a high-speed range.

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Key Stator / Armature Components

Stator Construction
TECO-Westinghouse Motor Company stators are designed and built to provide exceptional performance and outstanding reliability. The main poles and commutating poles are all laminated to assure quick response to speed and load changes. Our full-length commutating poles lower the reactance voltage and compensating windings provide proper compensation for armature reaction. Stator end connection joints are TIG-welded together for maximum strength. Compensating winding straps are individually bolted at the centerline split to allow quick removal of the top half of the stator. All stator electrical conductors are made from copper.

Armature Coils
Laminated, rectangular copper conductors are individually insulated and bonded together with separators. The formed, full coils are wrapped with ground wall insulation. A protective binding of tape then covers the complete coil. After winding, multiple coats of insulating resin are applied to create a smooth surface that resists rust, moisture, chemical contamination and heat.

Superior Banding and Wedging
In a unique TECO-Westinghouse developed glass banding process, acrylic-treated glass tape is applied to the armature coil end-turns under controlled tension and temperature. This process creates solid, high-strength, pre-tensioned bands which restrict coil movement under the forces encountered in service. The TECO-Westinghouse armature wedge design prevents coil movement in the core and assures excellent coil heat transfer. Narrow, flush wedges allow unimpeded air flow along the air gap, and wedging eliminates the reduction of rotor iron heat dissipating surfaces that would normally be associated with core banding.

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Thermalastic® Insulation

Used in thousands of TECO-Westinghouse motors in the field since its introduction, Thermalastic® insulation has proven to be the industry's premier insulation system. Due to its unique structure, the dielectric material is locked in a stable elastic bond to form a barrier that withstands prolonged voltage stresses, moisture, abrasion, dirt and thermal cycling. Thermalastic® insulation is chemically stable in the most severe environments, making it well suited to the most rigorous applications of our DC motors. In less demanding DC applications, other insulation systems may be utilized.

Digard® Insulation

Digard® is a specially-developed epoxy powder used in the riser insulation system. The electro statically applied powder is preferentially attracted to the riser edges. As a result, the insulating material is actually thicker at critical edge areas. This coating is applied to the armature when hot, allowing the powder to melt and flow. This smooth, void-free surface provides long creepage paths and prevents carbon dust from adhering, thus eliminating the major cause of low insulation resistance in DC machines.

Arch-Bound, V-Ring, "Balanced-Spring" Commutators

Our V-ring commutators feature true arch-bound construction with fully centered "floating" bars to ensure concentricity and eliminate distortion. The major "spring-like" commutator components, such as the V-rings, copper overhangs and thru-studs are specifically designed to assure uniform radial motion of the commutator bars at operating speed and temperature. This "balanced-spring" feature provides a smooth, brush riding surface under thermal and centrifugal forces thus assuring maximum brush life. Longitudinal thru-studs permit a convenient check for commutator tightness. All commutators are fully seasoned at rotational speeds.

Self-Aligning Bearings

The self-aligning, spherical seat bearings utilized on TECO-Westinghouse Motor Company DC motors are designed and engineered for continuous, reliable performance and easy maintenance. The bearing caps are removable and the bearing is split for easy inspection. The bearing units provide excellent heat transfer from babbitt to oil and to the pedestal. Oil ring lubrication is simple, effective and trouble free. When required, these bearings are also offered with internal disc lubrication or forced lubrication. Where special low friction starting is required or for continuous operation at very low speeds, hydrostatic lift can be supplied. A number of surface configurations are available depending on the magnitude of the thrust force.

TIG Welded Connections

Tungsten inert gas (TIG) welding is used to connect the armature coils to the commutator risers and the inner pole and pole face winding connections. This method of joining copper to copper produces a connection that has high strength, is low in resistance and is free of oxides, thereby assuring electrical, mechanical and thermal superiority.

Keyless Couplings

TECO-Westinghouse pioneered the use of keyless couplings thus eliminated the problem of slippage under heavy torque, which is often associated with key-type couplings. Our keyless couplings are shrunk on the shaft with high interference fits that provide a strong bond. Special fittings and grooves allow the couplings to be removed and even installed using hydraulic pressure. Key-type couplings can be designed where specific applications call for them.

Sturdy Frame Construction

Our large DC motors feature laminated steel frames for faster response and exceptional electrical performance. The commutation flux more easily follows the rapid changes in load current, resulting in better commutator. The lower frame time constant allows voltage changes to respond more quickly to regulator demands.

A variety of frame types are offered. Either bracket, stand-up solid, or stand-up laminated are available depending on machine size and application. Each of these frame types is specifically engineered to ensure optimum flux carrying capability, while providing adequate strength to transfer torque to the foundation and to hold its shape under magnetic forces.

Split-frame construction enhances the maintainability of our DC machines. The top half of the frame can be removed for thorough cleaning, inspection, and quick access to all internal parts without disturbing motor alignment.

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Multiple Armatures

Depending on your specific application, the TECO-Westinghouse Motor Company can provide double, triple, even quadruple armature motor designed to deliver the required torque while minimizing the inertia of the drive-train. A special two bearing double armature is available in some sizes which offers low inertia while being very compact.

Cutaway of DC Motor

  1. Coupling
  2. Spider
  3. Armature Laminations
  4. Armature Cross-Connections
  5. Main Pole
  6. Main Field Winding
  7. Lift-away End Cover
  8. Frame
  9. Compensating Winding
  10. Frame Brush Rigging Arms
  11. Armature Coils
  12. Riser
  13. Brush Holder Brackets
  14. Brushes
  15. Commutator Bar
  16. Commutator Spider
  17. Shaft
  18. Bearing
  19. Spherical Seat
  20. Oil Rings
  21. Oil Reservoir
  22. Pedestal
  23. Bedplate

A History of Firsts

Our presence as a world leader in the engineering and production of DC motors is built upon a distinguished record of pioneering achievement in the steel and mining industries.

Working with the steel industry, Westinghouse developed and installed the:

  • First electric motors in an American steel mill (1891)
  • First electric drive for main rolls
  • First reversing mill drive
  • First large twin-motor reversing mill drive

Some of our significant achievements in the mining industry include the:

  • First application of separately excited shunt-wound DC motors
  • First Ward Leonard dragline systems
  • First vertical swing motors
  • First laminated frame generators
  • First dual circuit generator system
Among the many Westinghouse "firsts" in the history of DC motors was the nation's first reversing rolling mill motor (pictured above), which was installed in 1905.

Perpetuating a proud tradition, TECO-Westinghouse has continued through the years to refine our DC motor product lines with quality enhancing features that secure our position of leadership within the marketplace.