UNI-T UT313 - Page 17

d. Preformed winding squirrel-cage induction electric motor
50.8
63.6
38.1
50.8
25.4
25.4
Sync rotating speed
720~1499
1500~2999
3000
Peak-peak displacement amplitude ( m)
Plastic support
Rigid support
The standard is formulated by American Petroleum Institute.
29
30
Notes: for AC electric motor, use highest sync rotating speed; for DC electric
motor, use the maximum power rotating speed; and for serial and
multipurpose electric motor, use working rotating speed.
c. the maximum allowable vibration for large electric motor
NEMA MG1-20.52
Peak-peak displacement amplitude
Rotating speed
3000 and higher
25.4
1500~2999
999
50.8
1000~1499
63.6
76.2
The above two standard are formulated by National Electrical Manufacturers
Association (NEMA)
e. ISO/IS2373 the electric quality standard based on vibration speed amplitute
80<H<132 132<H<225 225<H<400
Quality grade
600~3600 1.8 2.8
4.5
N Normal
600~1800
1800~3600
0.71
1.12
1.12
1.8
1.8
2.8
600~1800
1800~3600
0.45
0.71
0.71
1.12
1.12
1.8
R Good
S Special
Rotating speed
Axis height H mm
maximum speed vibration rms(mm/s)
r/min
r/min