Delta Electronics VFD-EL User Manual
Appendix C How to Select the Right AC Motor Drive|
Revision August 2008, 2ELE, V1.02
C-7
motor drive operates more than one motor, please pay attention to starting and changing
the motor.
Power Transmission Mechanism
Pay attention to reduced lubrication when operating gear reduction motors, gearboxes, belts
and chains, etc. over longer periods at low speeds. At high speeds of 50/60Hz and above,
lifetime reducing noises and vibrations may occur.
Motor torque
The torque characteristics of a motor operated by an AC motor drive and commercial mains
power are different.
Below you’ll find the torque-speed characteristics of a standard motor (4-pole, 15kW):
AC motor drive
Motor
180
155
140
100
80
55
38
38
0320 60
120
60 seconds
Base freq.: 60Hz
V/F for 220V/60Hz
180
155
100
55
38
38
0320 60
120
to
rq
ue
(
%
)
Frequency (Hz)
Frequency (Hz)
60 seconds
60 seconds
to
rq
u
e (
%
)
Base freq.: 60Hz
V/F for 220V/60Hz
130
140
100
85
45
35
0320 50
120
180
150
100
45
35
35
0
50
120
68
80
to
rq
ue
(
%
)
to
rq
u
e
(
%
)
60 seconds
60 seconds
Frequency (Hz)
Frequency (Hz)
3 20
Base freq.: 50Hz
V/F for 220V/50Hz
Base freq.: 50Hz
V/F for 220V/50Hz