16
When using IGBT inverters, high voltage peaks may arise in the motor due to the
switching action of the inverter output devices. These voltage peaks may damage the
insulation of the motor winding and must be taken into account when using motor cables
longer than 15m with high frequency motors. In this case, the motor can be protected
with a motor choke, dv/dt filter or sine filter.
When doing an insulation measurement in accordance with VDE 0100 / Part 620, the
power semiconductor of the unit and existing radio interferience filters must be
disconnected because of the danger of destruction. This is permissible in compliance
with the standard, since all inverters are given a high voltage test in the end control at
KEB in accordance with EN 50178.
When using components without isolated inputs / outputs, it is necessary that equipotential
bonding exists between the components to be connected (e.g. through the equalizer).
Disregard can cause destruction of the components by the equalizing currents.
A trouble-free and safe operation of the frequency inverter / servo drive is only
guaranteed when the connection instructions below are strictly followed. Incorrect
operation or damage may result from incorrect installation.
•
Note mains voltage and rated motor voltage.
•
Do not swap around mains and motor lines.
•
Install power cables and control cables separately (>15 cm separation).
•
Use shielded / twisted control lines. Connect shield to PE at inverter only.
•
Only use suitable circuit elements to control the logic and analog inputs, whose
contacts are rated for extra-low voltages.
•
Make sure inverter and motor housing are well grounded. The screen of the power
cable must be directly and securely attached to both the inverter PE terminal and
the motor ground terminal. Remove paint finish where necessary.
•
Connect the braking module / braking resistor with shielded / twisted cables (install
shield on one side of the inverter).
•
Ground the cabinet or the system earth star point with the shortest connection to
mains earth (avoid earth loops).
It is imperative to monitor the braking resistance temperature switch so as to avoid a
braking resistance overload. To do so, connect the sensor to T1 (OH) and T2 (OH) as
described in Part 2 of the instructions. If the braking transistor is defective, however, this
measure will not suffice to prevent an extreme overload and acute danger of fire. This
type of danger can only be averted by disconnecting the mains voltage (see diagram).
Overloads may be caused by:
•
the ramps being too short or the operating time too long
•
incorrect dimensioning of the braking resistance
•
the input voltage being too high
•
defect of the braking transistor in the inverter or braking module
Insulation
Measurement
Different Earth -
Potentials
Prevent
Disturbances
Voltage Peaks
Fire hazard
230 or 24 V AC/DC
drive
Braking resistance
with temperature
switch
at 24 V AC/DC
check tripping
Frequency inverter / servo
L1
L2
L3
L1
L2
L3
(+) PA
PB
PA
PB
OH1
OH2
U
Содержание COMBIVERT Series
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