Bypass Motor Control (Example) - Johnson Controls VSD II Series Installation Manual

Engineering
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.
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).

Bypass Motor Control (Example)

L1 L2 L3
Q1
I > I > I >
Q11
L1 L2 L3
T1 U V W
S1
M
M1
3~
Item
Number Description
1 Input/bypass contactor
2 Output contactor
8 VSD Series II LIT-12011772—October 2012 www.johnsoncontrols.com
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.
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 (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
CAUTION