40 Planning the electrical installation
Selecting the supply disconnecting device (disconnecting
means)
Install a hand-operated supply disconnecting device (disconnecting means) between
the AC power source and the drive. The disconnecting device must be of a type that
can be locked to the open position for installation and maintenance work.
European union
To meet the European Union Directives, according to standard EN 60204-1, Safety of
Machinery, the disconnecting device must be one of the following types:
• a switch-disconnector of utilization category AC-23B (EN 60947-3)
• a disconnector having an auxiliary contact that in all cases causes switching
devices to break the load circuit before the opening of the main contacts of the
disconnector (EN 60947-3)
• a circuit breaker suitable for isolation in accordance with EN 60947-2.
Other regions
The disconnecting device must conform to the applicable safety regulations.
Checking the compatibility of the motor and drive
Check that the 3-phase AC induction motor and the drive are compatible according to
the rating table in section Ratings on page 374. The table lists the typical motor power
for each drive type.
Only one permanent magnet synchronous motor can be connected to the inverter
output.
Checking the compatibility of the drive when multiple
motors are connected to the drive
The drive is selected based on the sum of the connected motor powers. Typically,
overdimensioning of the drive and the use of external output chokes is
recommended.
When one drive controls several motors, only scalar control is possible. Motor
parameters (P
N
, I
2N
) are given as the sum of the nominal values of the motors.
Nominal speed is given as an average of the motors. It is recommended to limit the
maximum current according to the actual need and it should not exceed 1.1 · I
2N
(parameter 2003 MAX CURRENT).
When multiple motors are connected, the sum of the output cable lengths must not
exceed the maximum allowed cable length (see Maximum recommended motor
cable length on page 386). If motor contactors are used, switching the contactors
during run is not recommended.
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