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42 Start-up
Action
Check that the drive is ready for the brake chopper start-up:
• The supply and inverter units have been installed according
to the instructions given in their hardware manuals.
• The supply unit has been started up according to the
instructions given in the appropriate supply unit manual.
• The inverter units have been started up according to the
instructions given in the hardware manual and appropriate
firmware manual.
Close all cabinet doors.
Power switch-on
WARNING! Before the power switch-on, make sure that there are inverters connected to the
intermediate circuit. A rule of thumb: the sum of the inverter powers must be at least 30% of the
rated power of the brake unit (P
Too few inverters connected results in a low intermediate circuit capacitance. Upon the power switch-on, the
DC voltage will overshoot the controller voltage limit, causing an immediate switching to braking mode. High
brake current will blow the inverter DC fuses.
Close the disconnector of the supply transformer.
Switch on power to the drive and start the supply unit.
Operational checks
Make sure that it is safe to start the drive. Start the drive and
increase the rotation speed of the high-inertia motor that will
generate power to the drive intermediate circuit when it is
decelerated.
Deactivate the overvoltage controllers of all inverters
(parameter 30.30 Overvoltage control in the Primary control
program).
Make sure that the stop mode of the motor to be decelerated is
ramp stop (parameter 21.03 Stop mode in the Primary control
program) and set the deceleration time according to the drive
control mode in parameter group 23, 26 or 28.
Check that the brake chopper evokes and operates during the
deceleration of the high-inertia motor: Give a stop command to
the inverter running the motor.
Repeat the stop sequence a few times with higher rotation
speeds and shorter deceleration times.
value).
brmax
Additional information
See the supply and inverter
module hardware manuals and
other appropriate manuals on the
inside of the front cover.
Use a low speed at first.
For the inverter parameter
settings, see the appropriate
firmware manual.
Use a relatively long deceleration
time at first.
The DC voltage level during the
braking indicates the brake
chopper operation:
• Successful braking:
DC voltage level is: 1.2 · 1.35 ·
U1
max
• Unsuccessful braking:
DC voltage level exceeds 1.21 ·
1.35 · U1
and inverter trips
max
on overvoltage. See chapter
Fault tracing and
maintenance.
If the brake chopper does not
function at all, see chapter
Fault
tracing and
maintenance.
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