I. Service Commitment:

1. All of our products are in strict accordance with international standard production, and after the quality inspection department inspection factory.
2. Our electric motors are strictly in accordance with relevant stated regulation warranty.
3. Customers on product quality aspect of dissent, the company guarantees of responses within 12 hours.

II. Electric Motor Failure Analysis:
Asynchronous motors and Synchronous motors should often be inspected during operation so as to discover troubles and eliminate them in time, otherwise, failure may be caused by the troubles.
The most common troubles and the causes are as follows:As a professional electric motor manufacturers and suppliers, We summarize the common problems are as follows :

1. Mechanical troubles:
A. Overheating of the bearing. It is due to:
(a) Insufficient lubricant; (b) Contamination of the lubricant; (c) Obstruction of oil rings;
(d) Trouble on the surface of the shaft and the bushing being not smooth;
(e) Incorrect clearance between the shaft journal and the bushing;
(f) An inclined bearing; (g) excessive pressure of the shaft journal; (h) Production of shaft current.
B. Overheating of the roller bearings and ball bearings. It is due to:
(a) Insufficient or excessive lubricant grease; (b) Bending of the shaft;
(c) Excessive friction of the shaft;  (d) Foreign matter being present in the lubricant;
(e) Damage of balls or rollers of the bearing and etc.
C. Oil leakage and accumulation of oil in the electric motors are due to:
(a) An excessive lubricant in the bearing; (b) Impurity of the lubricant or the wrong viscosity;
(c) Uneven pressure in the slot and under the cover of the bearing.
D. Vibration of the electrical motor. The causes are as follows:
(a) The center line of the motor set being not in alignment;
(b) The motor being improperly installed on the base plate;
(c) Shaft being bent, or vibration of the shaft journal;
(d) The coupling being improperly installed;
(e) The pulley and the coupling of the rotor being not well balanced;
(f) Clearance between the shaft journal and bushing being too large;
(g) Breaking of the squirrel cage bars or end ring;
(h) Vibration of rotor core; (i) Uneven sinking of base plate;
(j) Insufficient rigidity of base plate;
(k) Resonance of vibration frequency of base plate and that of the motor;
(l) Belt pulley being improperly installed; (m) Poor operation of the driven unit;
(n) The collision phenomena and etc.
E. The eccentric rotor may be due to the looseness of the bushing; the displacement of the bearing; the deformation of the rotor and stator core; the bending of the shaft; and dissatisfactory balance of the motor.

2. Electrical troubles:
A. The starting trouble may be due to the wrong wiring, the breaking of circuit, abnormal working voltage, the excessive load moment or steady moment, and the trouble of the starting equipment.
B. Overheating. It is due to:
(a) The line voltage being higher or lower than the rated value; (b) Overload;  (c) Insufficiency of cooling air;
(d) The high temperature of the cooling air; (e) the short circuit between turns;  (f) Uncleanness of the motor;
C. Break-down of insulation. It may be due to:
(a) Excessively high working voltage; (b) Corrosion of acid, alkali or chlorine gases; (c) Dirt; (d) Overheating;
(e) Mechanical damage; (f) High humidity; (g) Storage under 0℃; (h) Absorption of moisture.

D. Low resistance of insulation. It is due to:
(a) Dirt; (b) High humidity; (c) Vapour condensation on the surface due to great variation of temperature;
(d) Breaking or aging of the insulation.

E. Burning of the collector ring and sparking of the brushes. It is due to:
(a) The poor grinding of the brush; (b) The brush in the brush holder being too tight to move;
(c) Dirt on the collector ring and brushes; (d) The rough surface of the collector ring;
(e) Low pressure on brushes; (f) The wrong grade of brush;
(g) Poor contact between the brush holder and the conductor;
(h) The insufficiency of number of brushes or the cross section of brushes being too small.

F. Arcing between collector ring. It is due to:
(a) The presence of copper graphite on the rings and the brush holders; (b) Dampness;
(c) The corrosion of moisture, acid or alkali gases;
(d) Open circuit between the rotor and the starting rheostat, and open circuit in the rheostat itself.