Reactive power or excitation current adjustment, brush fire has changed significantly. Exciter when reversing, brushes and commutating poor contact, contact resistance is too large. Commutator or slip ring oxidation film thickness uneven brush current caused by unbalanced distribution. Or sudden changes in load, as well as the sudden short circuit of commutating voltage distribution; overload and unbalanced units. Brush selection is unreasonable, unequal brush spacing; brush quality problems and so on.
2, mechanical factors
Commutator Center not are, rotor not balance, and unit vibration big, and reversing tablets between insulation protruding or reversing tablets protruding, and electric brush contact surface grinding not smooth, or commutator surface rough and caused contact bad, commutator surface not clean, all reversing very gas gap ranging, electric brush Shang spring pressure not uniform or size not suitable, electric brush in brush holds in too pine and occurred beat, or too tight has carbon brush in brush holds in card live has,. Unit operating speed or vibration to improve, Sparks will be reduced.