Engineering
04/10 MN04020001Z-EN
30
Bypass operation
If you want to have the option of operating the motor with the
frequency inverter or directly from the mains supply, the input
branches must be interlocked mechanically.
Connecting EX motors
Note the following when connecting explosion-protected motors
please:
• The frequency inverter must be installed outside the EX area.
• Note the branch- and country-specific standards for
explosion-protected areas (ATEX 100a).
• Note the standards and information of the motor manufacturer
regarding operation on frequency inverters - e.g. if motor
reactors (du/dt-limiting) or sinus filters are specified.
• Temperature monitors in the motor windings (thermistor,
thermo-Click) are not to be connected directly to frequency
inverters but must be connected via an approved trigger
apparatus for EX areas.
h
Caution!
Debounced inputs may not be used in the safety
circuit diagram.
A changeover between the frequency inverter and the
mains supply must take place in a voltage-free state.
i
Warning!
The frequency inverter outputs (U, V, W) must not be
connected to the mains voltage (destruction of the device,
risk of fire).
Figure 16: Bypass motor control (example)
h
Caution!
Debounced inputs may not be used in the safety
circuit diagram.
Switch S1 must switch only when frequency inverter T1 is
at zero current.
h
Contactors and switches (S1) in the frequency inverter
output and for the direct start must be designed based on
utilization category AC-3 for the rated operational current
of the motor.
Q1
I
>
I
>
I
>
Q11
S1
M1
T1
M
3h
L1
L2
L3
L1 L2 L3
UVW
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