ABB NBRA-6 Series, Руководство по установке и запуску

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Chapter 2 – Overview
Installation and Start-up Guide for NBRA-6xx 2-7
Selecting the Correct
ACS 600/Chopper/
Resistor Combination
1. Calculate the maximum power (P
max
) generated by the motor during
braking.
2. Select a suitable ACS 600* / braking chopper / braking resistor
combination for the application. The following condition must be met:
P
BRmax
> P
max
See Table 2-1 and Table 2-2 for P
BRmax
. The P
BRmax
values in the tables are
specified for the reference braking cycle (one minute of braking, nine minutes of
rest). If the actual duty cycle does not correspond to the reference cycle, the
maximum allowed braking power
P
BR
must be used instead. See Appendix B –
Maximum Braking Power for the calculation of P
BR
.
3. Check the resistor selection. The energy generated by the motor
during a 400-second period must not exceed the resistor heat
dissipation capacity
E
R
(see Table 2-1 and Table 2-2).
If the E
R
value is not sufficient, it is possible to use a four-resistor assembly in which
two standard resistors are connected in parallel, two in series. The E
R
value of the
four-resistor assembly is four times the value specified for the standard resistor.
Note: A resistor other than the standard resistor can be used.
However, the following conditions must be met:
• Resistor resistance value must not be below the resistance value of
the standard resistor.
• Resistor resistance value must not restrict the braking capacity
needed. The condition is met when:
• Resistor heat dissipation capacity (E
R
) must be sufficient for the
application (see step 3 . above).
P
max
<
P
max
= Maximum power ( P
max
) generated by the motor during
braking.
U
DC
= Voltage over the resistor during braking =
1.35 · 1.2 · 415 V d.c. (mains voltage is 380 to 415 V a.c)
1.35 · 1.2 · 500 V d.c. (mains voltage is 440 to 500 V a.c)
1.35 · 1.2 · 690 V d.c. (mains voltage is 525 to 690 V a.c)
R = Resistor resistance value (ohm)
U
DC
R
2
*Selection of the ACS 600 is affected also by other factors (eg. the output power required during
acceleration). See
ACS 600 Technical Catalogue for more information on selecting the ACS 600.