Hitachi RCUE40AG2 Service Manual page 167

Maintenance
Start-up method

Normally more than 22kW compressor has
due to its high start-up current.
All Hitachi self-sealed screw compressors of rated output more than 22kW adapt -
due to its high performance from the view of start-up current.
Like shown in the fi gure 9/18, at start-up, coil of the stator is connected as a star (
voltage is added to each phase. When motor is accelerated and compressor starts to run normally, the
connection is changed to a delta (

Start-up method:
At start-up ( At start-up (
The real wiring is shown in the below fi gure
1. The connection of U~X, V~Y and W~Z is a motor, which is inside of screw compressor.
2. At start (
3. At operation (

Real Wiring Real Wiring:
pag. 165
SMGB0003 rev.0 - 11/2006
) to add the power voltage to all phase fully.
Line voltage=1
connection) connection)
) connection 52C, 6C:ON 42C:OFF
) connection 52C, 42C:ON 6C:OFF
start-up, partly waiting start-up as well as normal start-up
At operation ( At operation (
start-up system
), and 1/root3 of power
6 6
connection) connection)