Commercial Power Source Switchover - Hitachi WJ200 Series Instruction Manual

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Commercial power source switchover

The commercial power source switching function allows you to switch the power supply
(between the inverter and commercial power supply) to your system of which the load
causes a considerable moment of inertia. You can use the inverter to accelerate and
decelerate the motor in the system and the commercial power supply to drive the motor
for constant speed operation.
To use this function, assign parameter
[1] to [7] (C001
being given, the inverter waits for the retry wait time before motor starts (b003),
adjusts the output frequency to the speed of the free-running motor, and then
accelerates the motor with the adjusted frequency.
Mechanically interlock the MC3 and
MC2 contacts with each other.
Otherwise you may damage the drive.
If the earth leakage breaker (ELB) trips
because of a ground fault, the commercial
power will be disabled. Therefore, contact
a backup power supply from the
commercial power line circuit (ELBC) to
your system if needed.
Use weak-current type relays for FWY, RVY, and CSY. The figures below show the
sequence and timing of operations for reference.
Switching from inverter to commercial power
MC1
MC2
MC3
FW
CS
Inverter
Operation
output freq.
If the inverter trips because of overcurrent when it starts the motor with frequency
matching, increase the retry wait time before motor starts (b003).
Option Terminal
Code Symbol
CS
14
Valid for inputs:
Required settings
Notes:
inverter may start the motor with 0 Hz if:
• the motor speed is no more than half of the base frequency, or
• the voltage induced on the motor is attenuated quickly.
to C007). When the CS is turned OFF with an operation command is
ON
ON
ON
ON
ON
Function Name
Commercial power
source switchover
C001~C007
b003, b007
"14 (CS)" to one of the intelligent input terminal
ELBC
NFB
MC1
FWY
RVY
CSY
Switching from commercial power to inverter
MC1
MC2
ON
MC3
FW
CS
Inverter
0.5 to 1 s
output freq.
State
ON
OFF
MC2
MC3
WJ200
R U
S V
T W
FW
RV
CS
L
ON
Duration of the interlock of
MC2 and MC3 (0.5 to 1 s)
ON
ON
ON
Retry wait time b003
Start with freq. matching
Description
THRY
Motor