5.Maintenance

5.1 Knock-down examination

  For motors running continuously day and night , a knock-down examination should be made every 2 or 3 years.  However , for motors designed for special purposes , knock-down examinations should be made in certain time periods prescribed respectively .

5.2 Records

  1. Every day records

  1. At what time (year, month, day and hour) and in what weather the test is conducted .

  2. Voltage. load current . frequency (see 5.2C).

  3. Ambient temperature (room temperature).

  4. Temperature and noise around bearings.

  5. Temperatures in stator windings and on frame surface (totally enclosed type). See 5.2C.

  6. Abnormal vibrations and noise (see sections 7 and 8).

  1. Records of periodical test and inspection

  1. Insulation resistance and the relative humidity (see 4.1D).

  2. Amplitude of vibration (see 5.2C and section 7).

  3. The color and contents of grease discharged from bearings.

  4. Dirt lodged in and on the motor.

  5. Coupling allowance of coupling device; the tension of belts.

  6. Fastening bolts for base . foot and other parts.

  7. In case of oil lubrication , surface condition and clearness of the oil should be recorded. At the same time , check and make sure there is no leakage.

  1. Some of the values obtained by above-listed tests and inspections are variable; their variable ranges given below :

  1. The variation of voltage must be within ±10% of rated voltage.The variation of frequency must be within ±5% of rated value . when rated voltage is applied. when voltage and frequency varies at the same time , the result of absolute values of the two variations must be within ±10%.

  2. Temperature rise (maximum ambient temperature of 40¢J) by TM and RM are listed below :

TM : THERMOMETER METHOD

RM : RESISTANCE METHOD

Part Insulation A Class E Class B Class F Class H Class
Type TM RM TM RM TM RM TM RM TM RM
Stator Windings Types other than TEFC 50 60 65 75 70 80 85 100 105 125
TEFC 55 60 70 75 75 80 90 100 110 125
Rotor Windings Types other than TEFC 50 60 65 75 70 80 85 100 105 125
TEFC 55 60 70 75 75 80 90 100 110 125
Bearing

40¢J when test is made at the outer surfaces.
45¢J when test is made by inserted thermometer. However , when hotresist grease is used for lubrication , the temperature rise can reach as high as  55¢J.
  1. Vibration (see Section 7 for detailed information)

Bearings : When their service life is compared with that of windings , the allowable values , when motors are running with load are listed below :

25 - 30£g for 2-pole motors

50 - 60£g for 4-pole motors

70 - 80£g 6-and -more-pole motors

In case the vibration measured exceeds the above listed values , please check and find out the trouble , and corrective measures be adopted soonest .

5.3 In case periodical maintenance is necessary , it shoul be done in accordance with the table    attached at the end of this pamphlet .

Check on receipt | Installation | Means of coupling | Running | Maintenance | Bearing maintenance | Vibration | Noise | back