49
7. WIRING [Connecting a Power Cable]
Immediately after disconnecting the power, the
inverter is still live. Before servicing the start-
er/control box, therefore, make sure that the
inverter’s charge indicator is off or wait for 10
minutes after disconnecting the power.
CAUTION
■
Other Operating Precautions
(1) A thermal relay is not provided on the main circuit of
the inverter-controlled
DSP
. Instead, the electron-
ics-type thermal relay is built into the inverter for
protecting the main circuit.
(2) Phase failure is only enabled immediately after con-
necting the power. If a phase failure occurs during
operation, it is not detected and eventually causes the
inverter to overheat. Tightly fasten, therefore, the
cables/wires.
(3) Do not install a power-factor enhancing capacitor on
the motor side. Failure to observe this may cause the
inverter’s capacitors to receive the larger charging
current, resulting in a failure of the inverter.
(4) If radios, TV sets, or any other electronics devices
are located around the
DSP
, install the HITACHI
noise filters (as specified below) on the power cable.
(5) The inverter in the starter is attached with a digital
operator for setting and operating the inverter.
Hitachi has finished adjusting the digital operator to
the appropriate settings, before shipping the
DSP
from the factory.
Do not operate the attached
digital operator;
otherwise the inverter may mal-
function and cause a problem.
(6) In the cases below
①②
, a surge voltage may be gen-
erated in the inverter input side, which may cause a
inverter failure. In such cases, install an AC reactor
shown in the following table between power and the
air compressor.
①
An phase advance capacitor
installed between power and the air compressor
opens and closes.
②
The maximum voltage imbal-
ance between the phases shall be over 1%.
Recommended AC reactor
Model
AC reactor
160VWN
ALI-300H2
240VWN
ALI-420H2
Description
160VWN 240VWN
Functions
Zero phase
reactor
400V
class
ZCL-B95
Reduction of noise to
radio etc.
Radio noise
filter for input
400V
class
CFI-H
Reduction of radiation noise
from the power cable
Noise filter
for inverter
400V
class NF-H400 NF-H700
Reduction of normal noise and
common noise from the power cable
