What problems should the motor pay attention to during operation?

What problems should the motor pay attention to during operation?

The problem that the motor should pay attention to during operation:

(1) The motor is generally designed to operate at a location where the altitude does not exceed 1000 m and the ambient air temperature does not exceed 40 °C.
(2) When the motor is within ±5% of the additional voltage change, it can run continuously at the rated rate. If the voltage variation exceeds ±5%, the load shall be limited according to the manufacturer's specifications or test results.
(3) The temperature rise of the motor during operation should be in accordance with the manufacturer's regulations. If there is no such data, refer to Table 1-1.
 
Table 1-1 Temperature rise limits of air cooled motors
Item number
Motor parts
Class A insulation
Class E insulation
Class B insulation
Class F insulation
Class H insulation
Thermometer method
Resistance method
Thermometer method
Resistance method
 
Thermometer method
Resistance method
Thermometer method
Resistance method
Thermometer method
Resistance method
1
AC winding for small and medium-sized motors
50
60
65
75
70
80
85
100
105
125
2
DC-excited field windings (except for Phase 4 and Phase 5)
50
60
65
75
70
80
85
100
105
125
3
Armature winding with changer
50
60
65
75
70
80
85
100
105
125
4
Compensation winding and multilayer low resistance field winding
60
60
75
75
80
80
100
100
125
125
5
Exposed single layer winding
65
65
80
80
90
90
110
110
135
135
6
Permanently shorted insulated winding
60
-
75
-
80
-
100
-
125
-
7
Permanently shorted insulated winding
Hazard values ​​that should not cause damage to adjacent insulation
8
Core and other parts not in contact with the winding
9
Core and other components in contact with the winding
60
-
75
-
80
-
100
-
125
-
10
Steering gear or collector ring
60
-
70
-
80
-
90
-
100
-
 
(4) For short-time rated motors, the temperature rise limit of each part of the motor is allowed to increase by 10K compared with the value specified in Table 1-2.
(5) The allowable temperature of the sliding bearing is 80 ° C (when the oil temperature is not higher than 65 ° C). The allowable temperature of the rolling bearing is 95 ° C (the ambient temperature does not exceed 40 ° C).
(6) If the maximum ambient temperature of the motor is between 40 °C and 60 °C, the temperature rise limit specified in the above table shall be subtracted from the ambient temperature exceeding 40 °C.
(7) If the ambient temperature of the motor is between 0 °C and 40 °C (for example, t ° C), the temperature rise limit generally does not increase. When an agreement is made with the manufacturer, an increase of (40-t)K is allowed, but the maximum is 30K.
Cage asynchronous motors that are frequently started at full voltage should pay special attention to their heating.
(8) In order to avoid moisture, the motor that supplies cooling air to the outside must stop the supply of cooling air in time.
(9) Check if the spark under the brush is normal and the collector ring (or steering gear) is burnt and worn.
(10) Check if the motor has abnormal noise and vibration during operation, and whether the stator and rotor are in phase friction.
(11) The allowable vibration value (double amplitude) of the motor is shown in Table 1-2.
 
 
Table 1-2 Allowable vibration values ​​of the motor
Speed ​​/ (rmin)
Vibration value / mm
Speed ​​/ (rmin)
Vibration value / mm
3000
0.06
1000
0.13
1500
0.10
750 or less
0.16

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