Weq CTW900, Руководство пользователя

Страница: 143 / 144

Technical Specifications .
CTW900 | 143
   
2 T 1 T
2 T 135 1 T 60
I
2 2
ef

  

.
Since T1 = 2.5 minutes and T2 = 7.5 minutes, then I
ef
= 120.7A.
Thus, the rated current of the converter output must be above 121A.
The closest converter to this value is the
125A . For this model, the maximum output current is 156.2A
(125A x 1.25), and since the maximum current peak of the load cycle is below that (135A), the choice of
the 125-A converter is correct.
4. Finally, once the ambient temperature and the altitude are below 40 °C and 1000m, it is not necessary
to apply the ratio-corrector factors.
Therefore, the most suitable model for the relevant application would be the
CTW900A0125T05SZ .
However, besides the converter model to be used, it is important to observe some other points:
■
Check if the motor field current is smaller or equal to the maximum current accepted for the model,
according to Table 4.1;
■
Make sure the line voltage is compatible with the motor armature voltage, according to Table 10.1. If
possible, use the lowest input voltage that allows obtaining the output voltage, because that improves the
regulation;
■
Confirm if the field supply can be maintained with the standard internal connection, derived from the input
(R/S/T). If the armature supply voltage is too high for the field supply, make its feedback externally, as
described in item 5.3.2. In order to do so, take into account the values of Table 10.3.
Table 10.3 – Recommended voltages for field feedback
Field Rated Voltage [U
f
] Field Supply Voltage
U
f
 190 V
DC
220 V
AC
190 V
DC
< U
f

330 V
DC
380 V
AC
330 V
DC
< U
f
< 380 V
DC
440 V
AC