Eaton PowerXL DC1 Series - Speed Behavior Without Slip Compensation

6 Drives control
6.3 Motor
112 DC1 variable frequency drive 12/13 MN04020003Z-EN www.eaton.com
6.3.4 Speed behavior without slip compensation
On the constant three-phase AC supply, the three-phase asynchronous
motor has a constant rotor speed (n
1
, P-10, rating plate specifications)
according to the number of pole pairs and mains frequency. The slip here
represents the difference between the rotating field of the stator and that of
the rotor. In static operation, the slip is constant.
Load changes () at the motor shaft cause a larger slip (n) and thus a
reduced rotor speed ().
In controlled operation (V/F characteristic curve), the variable frequency drive
cannot compensate this load-related speed difference. The speed behavior
of the motor corresponds to that of a motor in a constant AC supply system.
Figure 67: Speed behavior Without slip compensation
D n
M
M
2
M
1
n
1
n
2
n
a
b