Planning The Braking System; Restrictions - ABB ACS880-104 Hardware Manual

326 Resistor braking using frame R1i...R4i inverter modules

Planning the braking system

•
The continuous and maximum braking power ratings of individual inverter modules are
listed on page 331.
The total continuous braking power of parallel-connected modules is calculated with
the formula
P = P
brcont
where P , P
brcont1
largest to smallest.
The total maximum braking power of parallel-connected modules is calculated with the
formula
P = P
brmax
where P , P
brmax1
largest to smallest.
•
The resistance of the resistor must not be lower than R
any inverter module to its resistor must not exceed the heat dissipation capacity (E
of the resistor.

Restrictions


•
Internal brake choppers are only available for frame R1i...R4i, ACS880-104-xxxxx-3
and ACS880-104-xxxxx-5 inverter module types.
•
The maximum number of modules doing the braking is 12 frame R1i...R2i modules or
6 frame R3i...R4i modules, ie. the number of modules that can be mounted into a
800 mm wide Rittal TS 8 cubicle.
•
Each inverter module must have its own resistor(s).
•
In case the braking power of the modules is not sufficient, a separate brake chopper
must be used. It is not allowed to use the internal brake choppers simultaneously with
a separate brake chopper.
•
The cubicle with the braking modules must be next in the line-up to the inverter that
needs to be braked.
•
The internal brake choppers cannot be used if the system has an IGBT (regenerative)
supply unit.
+ 0.8 × (P
brcont1 brcont2
, etc. are the P
brcont2
+ 0.7 × (P
brmax1 brmax2
, etc. are the P
brmax2
+ P + ...)
brcont3
values of the connected modules from
brcont
+ P + ...)
brmax3
values of the connected modules from
brmax
min.
The energy transferred by
)
R