Hitachi YUTAMPO Series Service Manual page 45

4 Electrical checks of main parts
Outdoor unit
This circuit full-waves rectifies 230 VAC applied between terminals L and N and boosts it to a required voltage with the
IPM to create a DC voltage.
The voltage become 300-330 V when the compressor is operated.
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Main parts
Name
Intelligence power module (IPM)
Diode stack (DB601)
Smoothing capacitors (C021-C022, 375 μF, 420 V) This smoothes (averages) the voltage rectified by the diode stack.
IGBT to improve efficiency (Q601)
37 SMGB0135 rev.0 - 06/2020
A module that constitute by an inverter part.
In case of intelligence power module malfunction or connection failure
immediately after compressor starts, its may stop due to error of abnormal low
speed, switching failure, Ip stop and others.
These rectify the 230 VAC from terminal L and N to a DC power supply.
If diode stack (DB601) are faulty, DC voltage may not be generated and the
compressor may not operate at all. Also be aware that the 15A fuse might have
blown.
It will improve the efficiency during compressor load become heavy when current
flow through the chopper period of Q601.
Description
4