Chapter 5—Motor and Application
22 DG1 Series VFD MN040002EN—March 2014 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 circuit
diagram.
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 15. Bypass Motor Control (Example)
Table 16. Bypass Motor Control 
Debounced inputs may not be used in the safety circuit
diagram.
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 
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— 
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.
Item No. Description
1 Input/bypass contactor
2 Output contactor
Q1
I
>
I
>
I
>
Q11 
S1 
M1 
T1 
M 
3~
L1
L2
L3
L1 L2 L3
UVW