Motor Brush / Twin Springs

Vulcan Spring is a leading designer and manufacturer of motor brush / twin springs for use in electric motors. This category consists of Conforce ® constant force springs, back plate assemblies, twin springs, saddle springs and spiral torsion springs. Vulcan Spring specializes in springs that minimize space, maximize brush life and meet exacting force requirements ensuring consistent, dependable power to electric motor commutators.

Electric motor manufacturers need high quality, long-lasting motor springs, and Vulcan Spring delivers. Motor brush springs can be found in:

  • DC motors carbon brush assemblies
  • Back plate assemblies that snap in for ease of installation,
  • Car seat and windshield wiper motors, and many other automotive applications
  • Train and locomotive applications

Custom Motor Brush Springs

Vulcan Spring specializes in making custom motor brush springs to customer specification. With Vulcan Spring’s design, engineering and manufacturing prowess, custom motor brush springs can be produced in almost the same time as stock springs. “Custom” is normal for Vulcan Spring and this has been proven to customers over and over again.

How to Work with Vulcan Spring for Custom Motor Brush Springs

Vulcan Spring works with our clients at various stages of their product development process with DFM (design for manufacturing) principles. We are design experts with over 40 years' experience in designing and delivering cost effective products in volume. In addition, Vulcan offers a broad range of fully engineered springs from our extensive portfolio of products.

The design and engineering process includes:

  • Initial Design Review,
  • Prototyping
  • Testing
  • Production – Short run or long run production

Technical Considerations for Motor Brush Springs

A twin spring or motor brush spring is typically specified and engineered with the following in mind:

  • Materials - Type 301 stainless steel typically produces the best part at the lowest cost, but other materials are required if current is to be carried through the spring.
  • Single or Twin Coil Design guides for reference:
    Conforce Design Guide B: Spring Life = 3,000 cycles (Single coil) (Metric)
    Conforce Design Guide T: Spring Life = 3,000 cycles (Twin coil) (Metric)

  • Force requirements - the force of the spring should be equal to the spring force required to obtain the desired brush pressure. The normal tolerance for a constant force motor brush spring is +/- 10%.
     Motor Brush Clearance
  • Available space - for any given force there are several combinations of spring thickness and width to best fit the available space.
  • Size
    • Maximum available outside diameter
    • Maximum width of spring
    • Working extension
    • Length - include two full turns extra when the spring is fully extended, based on the length of the brush when new.
  • Configuration-
    • Straight extension spring/a single spring
    • Laminated springs/multiple interwound springs
    • Twin coil springs/doubles the load of a single spring
  • Clearance - start with ten times the thickness of the spring and allow clearance for spring cross-curvature which varies with spring width
  • End detail - applies to standard brush springs but not for twin springs. Vulcan Spring has many standard dies to create the end detail. Special end designs can be made for a nominal charge.

       View End Details  
  • Mounting Methods - Vulcan Spring offers a variety of single and twin coil mounting recommendations; see image.

motor brush spring

twin spring or motor brush spring


Applications / Uses for Motor Brush Springs

Industries that use motor brush springs include:

Vulcan Spring’s Manufacturing Process for Motor Brush Springs

Vulcan Spring utilizes highly customized production equipment, lean manufacturing techniques and principles, and ISO 9001:2008 certified procedures to provide our customers with a streamlined and efficient manufacturing process.

Benefits of working with Vulcan Spring include reduced lead times, high quality control and highly competitive costs.

Contact Vulcan Spring for Motor Brush Springs

Complete the twin spring / motor brush spring specification form for further assistance with motor springs, brush springs, twin springs, saddle springs and spiral torsion springs