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52 Start-up
Action
Check that the insulation of the resistor circuit has been meas-
ured and is OK.
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 respective manuals.
• The cooling unit has been started up according to the instruc-
tions given in its manual.
• The supply unit has been started up according to the instruc-
tions given in its manual.
• The inverter units have been started up according to the in-
structions given in its manuals.
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 (Pbrmax value).
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 decel-
erated. Use a low speed at first.
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 activates 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.
Additional information
See section
Checking the insulation
of the resistor circuit (page
43).
See the
Related manuals (page
For the inverter parameter settings,
see the appropriate firmware manual.
Use a relatively long deceleration time
at first.
The DC voltage level during the brak-
ing indicates the brake chopper oper-
ation:
• 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 on
max
overvoltage. See chapter
Fault tra-
cing (page
53).
If the brake chopper does not function
at all, see chapter
Fault tra-
cing (page
53).
10).
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