ABB ACS880 Firmware Manual page 322

322 Parameters
No. Name/Value
Enabled without
thermal model
Overvoltage peak
protection
43.07 Brake chopper run
enable
Off
On
Other [bit]
43.08 Brake resistor
thermal tc
0 ... 10000 s
43.09 Brake resistor
Pmax cont
0.00 ...
10000.00 kW
43.10 Brake resistance
0.0 ... 1000.0 ohm
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Description
Brake chopper control enabled without resistor overload
protection based on a thermal model. 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.
Before using this setting, ensure that overvoltage control is
switched off (parameter 30.30 Overvoltage
Brake chopper starts to conduct at 100% pulse width
whenever the DC voltage exceeds the overvoltage fault limit
(a hysteresis applies). The thermal model-based resistor
overload protection is not active. During normal use, the brake
chopper is not operating.
This setting is intended for situations where
• the braking chopper is not needed for runtime operation, ie.
to dissipate the inertial energy of the motor,
• the motor is able to store a considerable amount of
magnetic energy in its windings, and
• the motor might, deliberately or inadvertently, be stopped
by coasting.
In such a situation, the motor would potentially discharge
enough magnetic energy towards the drive to cause damage.
To protect the drive, the brake chopper can be used with a
small resistor dimensioned merely to handle the magnetic
energy (not the inertial energy) of the motor.
Selects the source for quick brake chopper on/off control.
0 = Brake chopper IGBT pulses are cut off
1 = Normal brake chopper IGBT modulation allowed.
This parameter can be used to enable chopper operation only
when the supply is missing from a drive with a regenerative
supply unit.
0.
1.
Source selection (see Terms and abbreviations
Defines the thermal time constant for the brake resistor
thermal model.
Brake resistor thermal time constant, ie. the rated time to
achieve 63% temperature.
Defines the maximum continuous load of the brake resistor
which will eventually raise the resistor temperature to the
maximum allowed value (= continuous heat dissipation
capacity of the resistor in kW) but not above it. The value is
used in the resistor overload protection based on the thermal
model. See parameter 43.06 Brake chopper
brake resistor data sheet.
Maximum continuous load of the brake resistor.
Defines the resistance value of the brake resistor. The value is
used for the brake chopper protection based on the thermal
model. See parameter 43.06 Brake chopper function.
Brake resistor resistance value.
Def/FbEq16
2
control)
3
On
0
1
on page 112). -
0 s
1 = 1 s
0.00 kW
function, and the
1 = 1 kW
0.0 ohm
1 = 1 ohm