ABB ACS850 series, Firmware Manual

Page: 180 / 260

180 Parameters
47
47 Voltage ctrl Overvoltage and undervoltage control settings.
47.01 Overvolt ctrl Enables the overvoltage control of the intermediate DC link.
Fast braking of a high inertia load causes the voltage to rise
to the overvoltage control limit. To prevent the DC voltage
from exceeding the limit, the overvoltage controller
automatically decreases the braking torque.
Note: If a brake chopper and resistor or a regenerative supply
section are included in the drive, the controller must be
disabled.
Disable Overvoltage control disabled. 0
Enable Overvoltage control enabled. 1
47.02 Undervolt ctrl Enables the undervoltage control of the intermediate DC link.
If the DC voltage drops due to input power cut off, the
undervoltage controller will automatically decrease the motor
torque in order to keep the voltage above the lower limit. By
decreasing the motor torque, the inertia of the load will cause
regeneration back to the drive, keeping the DC link charged
and preventing an undervoltage trip until the motor coasts to
stop. This will act as a power-loss ride-through functionality in
systems with high inertia, such as a centrifuge or a fan.
Disable Undervoltage control disabled. 0
Enable Undervoltage control enabled. 1
48
48 Brake chopper
Control of the brake chopper.
48.01 Bc enable Enables the brake chopper control.
Note: Before enabling the brake chopper control, ensure that
a brake resistor is connected and the overvoltage control is
switched off (parameter
47.01 Overvolt ctrl ).
Disable Brake chopper control disabled. 0
EnableTherm Brake chopper control enabled with resistor overload
protection. 1
Enable Brake chopper control enabled without resistor overload
protection. This setting can be used, for example, if the
resistor is equipped with a thermal circuit breaker that is wired
to stop the drive if the resistor overheats. 2
48.02 Bc run-time ena Selects the source for quick run-time brake chopper control.
0 = Brake chopper IGBT pulses are cut off
1 = Normal brake chopper IGBT modulation. The overvoltage
control is automatically switched off
This parameter can be used to program the chopper control
to function only when the drive is operating in the generator
mode.
Const Bit pointer setting (see Terms and abbreviations on page 63 ). -
Pointer
48.03 BrThermTimeConst Defines the thermal time constant of the brake resistor for
overload protection.
0 … 10000 s Brake resistor thermal time constant. 1 = 1 s
48.04 Br power max cnt Defines the maximum continuous braking power which will
raise the resistor temperature to the maximum allowed value.
The value is used in the overload protection.
No. Name/Value Description FbEq