28
Chapter 5—Motor and application
POWERXL SERIES VFD MN040002EN—February 2018 www.eaton.com
Bypass operation
If you want to have the option of operating the motor with
the frequency inverter or directly from the input supply, the
input branches must be interlocked mechanically.
CAUTION
Debounced inputs may not be used in the safety
circuitdiagram.
A changeover between the frequency inverter and the input
supply must take place in a voltage-free state.
WARNING
The frequency inverter outputs (U, V, W) must not be
connected to the input voltage (destruction of the
device, risk of fire).
Figure 18. Bypass motor control (example)
Q1
I
>
I
>
I
>
Q11
S1
M1
T1
M
3~
L1
L2
L3
L1 L2 L3
UVW
Table 28. Bypass motor control
Item No. Description
1 Input/bypass contactor
2 Output contactor
CAUTION
Debounced inputs may not be used in the safety
circuitdiagram.
Switch S1 must switch only when frequency inverter T1 is
at zero current.
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.
Connecting EX motors
Note the following when connecting explosion-protected
motors:
•
The frequency inverter must be installed outside the
EXarea
•
Note the branch- and country-specific standards for
explosion-protected areas (ATEX 100 A)
•
Note the standards and information of the motor
manufacturer regarding operation on frequency
inverters— for example, if motor reactors or sine-wave
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