Monitoring Of The Single Phases - Baumuller b maXX BM3000 Operating Manual

4.11
Monitoring
Derating characteristic of asynchronous machines without forced ventilation
Standard asynchronous machines without forced ventilation normally require a derating
of the maximum continuous current at speeds lower than the rated speed.
Figure 233:
Two derating factors are provided which proportionally to the rated speed lower the max-
imum continuous current at the standstill point and at half the rated speed. Based on this
a current limit curve is interpolated from the available current values again and is used for
the calculation of the l
is fixed to the rated current if it is above the rated speed.
Figure 234:

4.11.5.3 Monitoring of the single phases

The standardized solution referring to the monitoring of the complete current is insufficient
for many applications at low speeds and in standstill. Therefore an implementation solu-
tion is presented which considers the output frequency effect lower than the thermal time
constant of the motor.
During slow motion the 3 phases are unequally loaded. By l
bit 3 to 1 instead of the l
separately for every phase
738 Parameter manual b maXX BM3000
Document no.: 5.12001.07
of 820
100
80
6.46[1]
60
40
6.46[0]
20
25 50
Motor speed / Nominal speed, %
Typical derating of standard asynchronous machines (without forced ventilation)
2
t actual value (see
I´ act
N
Nominal current
107.9
1
Speed actual value
18.22
6.46[0]
6.46[0], 6.46[1]
Motor I t derating factors
Speed-dependent l
75 100 125 150
ZFig.
233–). The maximum continuous current
N
D
D
I
Ref
Df
6.46[1]
N
N
2
2
t overload monitoring of asynchronous machines without forced ventilation
2
values of the apparent current the l
to Z47.34–). The "Motor l
(Z47.32–
(Self ventilated)
5000_0361_rev01.cdr
2
I values
5000_0362_rev01.cdr
2
t monitoring mode
2
values can be evaluated
2
t actual value"
Baumüller Nürnberg GmbH
Z6.43–
Z6.28–