Using of brush holders in electric motors

Using of brush holders in electric motors

Brush holders are important and integral part of commutator motors. These elements are mounted in electric motors, generators and other engines which use brush systems to transfer electrical contact to rotating parts.

Functions of brush holders

1. Brush support - provide mechanical support and fixing of brushes, pressing them against the rotating commutator. This is necessary to ensure stable electrical contact and prevent wear.

2. Current distribution - holders distribute an electrical current to brushes. They ensure right direction and distribute the current in a smooth manner, which reduces wear and increases engine efficiency.

3. Adjustment and Maintenance - Brush holders may have mechanisms to adjust the pressure of brushes on a commutator. This allows engineers to configure and maintain the system based on their needs and operating conditions.

Variety of brush holders

There are a variety of brush assemblies on the market, each designed for specific types of generators. Most common types:

1. Fixed - have a constant position and can’t be adjusted. Usually can be used in stationary engines and generators where there is no need to change position of brushes.

2. Adjustable - allow you to adjust position of a brush for optimal contact with a commutator. They are used in engines where there is an ability to customize the system.

3. Spring - ensures constant pressing of brushes to a surface of the commutator. This type of design reduces wear and ensures reliable contact in variable conditions.

4. Nested - allow you to install several brushes in a one holder, which reduces the size and simplifies the design.

Brush holders design

Most brush holders consist of: 1. A housing (metal or plastic). 2. Springs that create pressure on brushes. 3. Seats (boxes) in which brushes are fixed.

Common breakdowns

Like any other mechanism, brush holders can't work forever, and their components wear out and break. The most common problem is wear of the brushes, which are consumables and have to be replaced. When wear reaches 60-80%, there is not enough contact surface left on them to transmit current, which leads to surges and overheating. This can lead to fire and melting of the plastic brush holder housing, so you need to replace it.

Another common problem is deformation of the seat (box). A striking example is the brush holder in the Easytronic Opel robotic box. The ears of the clips, where the spring with the brush installed, are designed for one bend, which is carried out at the manufacturer. It happens that during the repair process, an inexperienced mechanic bends these ears, and when they are bent again, they simply break off. In this case the clips become completely unusable and must be replaced.

In our store you can purchase brush holders for restoring various current generators, as well as components for them. We offer assembled brush holders for Haldex coupling pumps of 1-3 generations, a plastic housing of the brush unit for Haldex pumps of the 4th generation, assembled brush holders for various models of Webasto and Eberspacher parking heaters, as well as clips (seats) for the brush holder of the Opel box easytronic, Frod Durashift EST, Honda I-Shift.