DHi's HiPerCon Brand Metal Fiber Brush FAQs

Metal Fiber Brushes and Their Advantages
What About Wear and Wear Debris?
Will Metal Fiber Brushes Work in My Application?
What Kinds of Metal Fiber Brushes Do You Offer?
HiPerCon and DHi

 

Metal Fiber Brushes and Their Advantages

What are metal fiber brushes? 

DHi's HiPerCon® Brand Metal Fiber Brushes (MFBs) are electrical and/or thermal contacts for use on both sliding and stationary applications. They are made up of many thousands of very fine flexible metal fibers. HiPerCon® brand metal fiber brushes make contact on the tips of the fibers, unlike other metal fiber brushes. This allows the brushes to maintain better contact with surfaces than comparably sized graphite and metal-graphite brushes and other metal fiber brushes. It also allows them to make much better electrical contact than other varieties of metal fiber brushes, where the fibers lay flat on the surface and touch only on the sides of a relatively small number of fibers.

What advantages do metal fiber brushes have over carbon brushes?

DHi’s HiPerCon® brand metal fiber brushes can carry much larger current than the same sized carbon brush whilst generating much less electrical and acoustic noise. They produce significantly lower levels of wear debris, are considerably less susceptible to atmospheric and liquid contaminants, and typically have lower wear rates than carbon brushes.

What advantages do brushed motors have over brushless motors?

Brushed motors are typically cheaper, weigh less, and are more energy efficient. Because metal fiber brushes eliminate many of the disadvantages of carbon brushes, MFB brushed motors may prove more attractive for your application.

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What About Wear and Wear Debris?

Will the metal wear debris generated by the brushes inside the machine increase internal grounds? 

No. The wear debris from HiPerCon’s metal fiber brushes has been extensively tested and is highly resistive, unless the wear debris is compressed under high pressure.

Will the metal fiber wear debris damage other internal machine components such as bearings?

No. Metal fiber brushes are made from relatively soft metals, so steel bearings and other machine components will not be damaged. Additionally, the MFB debris does not interact adversely with hydrocarbons, oils or other lubricants typical of carbon based brushes.

Why is there much less wear debris for MFBs than for the same size carbon brush?

Metal fiber brushes are designed so that the fibers inside the brushes can flex and bend. This flexibility allows them to maintain good contact with the slip ring surface. To allow the fibers to move inside the brush, much of the space is left intentionally empty. Typically only 10-20% of the metal fiber brush volume is occupied by fibers with the rest being empty space. Since metal fiber brushes have comparable or better wear rates than graphitic brushes, this will generate only about 10-20% of the wear debris of the graphite brushes for a given length of brush.

I noticed you specify wear rates using the metric “non-dimensional wear rate.” What does that mean?

A non-dimensional wear rate is calculated by dividing the length of the brush worn away by the distance the brush traveled on the rotor surface during that time. This number gives an indication of how fast the brush wears independent of surface speed, slip ring diameter, or run time.

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Will Metal Fiber Brushes Work in My Application?

Will HiPerCon brushes work in my machine?

In general, HiPerCon metal fiber brushes are appropriate for installation on many types of slip ring applications and will improve numerous aspects of machine performance. But they are not appropriate for all machine types. Please fill out and e-mail a copy of our easy-to-use Slip Ring Data Sheet to us and we will quickly respond with an evaluation of your application.

Point of Contact: Richard Martin
rmartin@dh-inc.com


Defense Holdings Inc.
9105-B Owens Drive, Suite 201, Manassas Park, VA 20111
703-334-2858, ext. 2866

 

What changes will be necessary to convert my device from carbon brushes to HiPerCon brushes?

Metal fiber brushes require much less pressure to load them against a slip ring than carbon brushes, so a reduction of the spring force will be necessary. We make an effort to modify as few components as possible during a retrofit. In some cases, however, changes in brush holder design are also needed.

What slip ring materials are preferred for use with metal fiber brushes?

Metal fiber brushes are typically run on copper, bronze, and other copper alloys in addition to silver or gold-plated slip rings. Metal fiber brushes may also be used on other slip ring types. Please contact us to discuss the use of other alloys that may be needed for additional applications.

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What Kinds of Metal Fiber Brushes Do You Offer?

What size brushes do you have in stock?

We only keep a few types of our MFBs in stock since there are an incredible variety of brush applications that our brushes can fit in; all with differing sizes, shapes, and properties. When you contact us, we will explore fitment of our  brushes to your application.

What are the largest or smallest size brushes you make?

We currently make brushes as small as 0.2” x 0.2” in cross section and as large as 1.4” x 1.2”. The maximum and minimum brush length depends on the brush holder and device arrangement, but brushes can currently be made as long as ~3”. If you are in need of larger or smaller brushes, please contact us to see if we can build a brush to fit your specific need.

What are the various brush shapes you can make? 

To date, we have made brushes that are square, rectangular, round, and hexagonal, but metal fiber brushes can be made in most any shape needed to fit your application.

Will metal fiber brushes work in DC commutating applications?

Commutating metal fiber brush technology is a less mature technology and retrofitting commutating motors is significantly more complicated. Development of a metal fiber brush for your commutating application may be possible with collaborative research.

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HiPerCon and DHi

Who is DHi and how are they related to HiPerCon?

DHi® and HiPerCon® are related through common ownership with the passing of two of HiPerCon’s original founders; Dr. Heinz G. Wilsdorf and Dr. Doris Kuhlmann-Wilsdorf.  DHi and HiPerCon worked together closely after the founding of  HiPerCon LLC in 1998. Our coordinated objective has been and continues today to develop metal fiber brush technologies for the benefit of our customers. DHi staff have provided program and project management and serves as point of contact for customers. Manufacturing also transitioned to DHi in 2010. HiPerCon retains the patents and Intellectual Property and controls any licensing arrangements with third parties.

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