Speed control
15
Application examples
15.5
L
15.5-4
EDS82EV903-1.0-11/2002
Conditions
l A 4-pole motor is to be operated up to n
max
= 1500 min
-1
. The motor has
the following data:
– Rated speed n
r
= 1390 min
-1
– Rated frequency f
r
=50Hz
– Slip s
r
=7.3%
– Slip frequency f
s
=3.7Hz
l The pulse encoder delivers 6 increments/revolution (inc/rev).
– The maximum frequency at X3/E1 at maximum speed is:
1500
60 s
â‹… 6 = 150 Hz
l Process controller influence (C0074) setting to 200 % rated slip:
– C0074 = 14.6 %
l Calculation of maximum output frequency (C0011):
ï…²
1 +
C0074 [% ]
100
ï…µ
â‹…
p
60
â‹… n
max
[min
−1
] = 1.15 â‹…
2 â‹… 1500
60
= 57.5 Hz
)
))
) Note!
If the number of increments per revolution is not known, you have
to find out the gain to be set by experiment:
l Set C0238 = 0 or 1.
l Set the drive to the maximum required output frequency. The
output frequency is now determined by the frequency
precontrol.
l Use C0426 to set the gain in a way that the actual value
(C0051) equals the setpoint (C0050).
Adjustment (see example in
Fig. 15.5-1)