Inverter Application Precautions; Selection - Omron VARISPEED G7 Instruction Manual

Inverter Application Precautions

This section provides precautions for selecting, installing, setting, and handling Inverters.

Selection

Observe the following precautions in selecting an Inverter.
Installing Reactors
A large peak current will flow in the power input circuit when the Inverter is connected to a large-capacity
power transformer (600 kVA or higher) or when switching a phase capacitor. Excessive peak current can
destroy the convertor section. To prevent this, install a DC or AC reactor (optional) to improve the power sup-
ply power factor.
DC reactors are built into 200 V class Inverters of 18.5 to 110 kW and 400 V class Inverters of 18.5 to 300 kW.
If a thyristor convertor, such as a DC drive, is connected in the same power supply system, connect a DC or
AC reactor regardless of the power supply conditions shown in the following diagram.
Inverter Capacity
When connecting special motors or multiple motors in parallel to an Inverter, select the Inverter capacity so
that the rated output current of the Inverter is 1.1 times the sum of all the motor rated currents.
Initial Torque
The startup and acceleration characteristics of the motor are restricted by the overload current ratings of the
Inverter that is driving the motor. The torque characteristics are generally less than those required when start-
ing using a normal commercial power supply. If a large initial torque is required, select an Inverter with a
somewhat larger capacity or increase the capacity of both the motor and the inverter.
Emergency Stop
Although the Inverter's protective functions will stop operation when a fault occurs, the motor will not stop
immediately. Always provide mechanical stop and protection mechanisms on equipment requiring an emer-
gency stop.
Options
Terminals B1, B2,
Never connect any other devices to these terminals.
DC or AC reactor
Power supply
Required
capacity (kVA)
Inverter capacity (kVA)
Fig 10.5
, 1, 2, 3 are for connecting only the options specifically provided by Yaskawa.
Inverter Application Precautions
DC or AC reactor
Not required
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