2-22
D Installing a Magnetic Contactor
If
the power supply of the main circuit is to be shut of
f because of the sequence, a magnetic
contactor
can be used instead of a molded-case circuit breaker.
When a magnetic contactor is installed on the primary side of the main circuit to stop a load forcibly,
however, the regenerative braking does not work and the load coasts to a stop.
• A
load can be started and stopped
by opening and closing the magnetic contactor on the primary side.
Frequently opening and closing the magnetic contactor, however, may cause the Inverter to break
down.
T
o maintain the service life of the Inverter
’
s internal
relays and electrolytic capacitors, it is rec
-
ommended that this operation be performed no more than once every 30 minutes.
• When the Inverter is operated with the Digital Operator, automatic operation cannot be performed
after recovery from a power interruption.
• When
using the Braking Resistor Unit, be sure to arrange a sequence
in which the thermal relay of the
Unit turns the magnetic contactor OFF.
D Connecting Input Power Supply to the Terminal Block
Input power supply can be connected to any terminal on the terminal block because the phase
sequence of input power supply is irrelevant to the phase sequence (R/L1, S/L2, and T/L3).
D Installing an AC Reactor
If the Inverter is connected to a large-capacity power transformer (660 kW or more) or the phase
advance capacitor is switched, an excessive peak current may flow through the input power circuit,
causing the converter unit to break down.
To prevent this, install an optional AC reactor on the input side of the Inverter.
This also improves the power factor on the power supply side.
D Installing a Surge Absorber
Always
use a surge absorber or diode for the inductive loads near
the Inverter
. These inductive loads
include
magnetic contactors, electromagnetic
relays, solenoid valves, solenoid, and magnetic brakes.
Installation Chapter 2
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