The Problems for Brush Gear

Item

Problem

Reason

Repair Solution

1

The brush is fragmented.

The electric spark is larger.

The operating surface connected between brush box and its commutator is not vertical.

The distance from brush box to its operating surface of the commutator is too high.

Brush hole is bigger or too loose.

Loosening fastening bolt and re-adjusting;

Adjust to 2-4mm;

Replace a new brush box.

2

After the brush is rotating forward and reversal, two wear surface are appeared.

Due to brush hole deformation and not-qualified squae hole process, flared end is generated or too loose square hole.

Replace a new brush box or equip a upper-limit brush

3

Due to the brush bounced, its electric spark is generated.

Commutator lug deformation;

Interlayer mica is projecting;

Copper thorn and cuspidal edge are generated;

Too low pressure of the brush.

Loosen fastening bolt and re-adjusting;

Replace undercut mica;

Re-chamfering;

Adjust pressure or replace spring;

4

The brush is over-heated.

Too larger pressure of the brush;

Due to unbalanced pressure among the brushes, its load is unbalanced.

Adjust pressure or replace spring;

Replace unequal-height brush and adjust the pressure of individual brush

5

The brush is worn too rapidly.

Too cleanliness level for the commutator and sharp corner of the burr is too larger.

Due to too lower load, the film cannot be generated.

Too dry or too moisture of its operating circumstance

Re-lathing and chamfering;

Rising load or reducing the quantity of the brush;

Improving operating circumstances or replace brush grade

6

The brush is jammed in its brush box.

Brush hole deformation;

Too larger dimension of the brush;

Due to too soft the brush, its carbon dust is jammed in its square hole.

Too short line of braid brushing;

Pressure finger is jammed and pressed down the brush.

Replace brush box or re-process square hole;

Grinding the brush appropriately;

Slight blow or replace brush grade;

Replace a new brush or solving jamming;

7

The pressure of the brush is larger.

Due to inefficient heat treatment for the spring, its hardness is insufficient.

Due to the ring fire of the motor, the spring is annealed after over-heated.

Replace a new spring or re-heat treatment

8

Brush-ring breakage

Too higher hardness;

Due to loose braid brush, the spring appears conductive.

Inefficient rivet joint of constant spring, its breakage is generated.

Replace appropriate hardness for the spring and select RO with 40-45;

Replace a new brush with insulating backing;

Replace a new spring and improve rivet process;

9

Brush-box vibration

Loose fastening components

Re-fastening

10

Brush-box sparkwear

Too larger spark or ring fire;

Due to inefficient running-in between the brush and the commutator, arc is generated.

Brush box is fallen off.

Eliminate ring fire to reduce electric spark;

Process qualified running-in;

Re-welding or fastening

11

Brush-rod ground breakdown

Due to dust accumulation cracked by plastic or epoxy brush rod, creepage and breakdown.

Flask is fractured.

Due to dust accumulation stricken from plastic brush rod to its external Polytetrafluoroethylene tube, its breakdown is generated.

Replace a new brush rod or improve process;

Replace a new china bottle;

Adopt one-shot-with-two-part mold to eliminate the gaps.

12

Loose Brush holder ring

Loose fastening and loose locating pin

Adopt positioning mark to better recovering and fastening;

Change a locating pin;