Description Of Main Circuit Operation - Hitachi RAM-40QH5 Service Manual

DESCRIPTION OF MAIN CIRCUIT OPERATION (OUTDOOR)
Model RAM-40QH5
1. Power Circuit
This circuit full-wave rectifies 220-240V AC applied between terminals L and N, and boosts it to a
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required voltage with the active module, to create a DC voltage.
The voltage becomes 260-380V when the compressor is operated
(1) System power module (SPM2)
(Surrent ACT module, smoothing capacitors
and power module are combined into one
unit)
Active module
1
The active filter, consisting of a reactor
and switching element, eliminates
higher harmonic components contained
in the current generated when the
compressor is operated, and improves
the power-factor.
Smoothing capacitor smoothes voltage,
2
which has been rectified by diode stack
and boosted at ACT section.
Power module section
3
Refer to item 3 System Power Module
Circuit.
(2) Diode stacks
These rectify the 220-240V AC from
terminals L and N to a DC power supply.
Fig. 1-1
< Reference >
In case of malfunction or defective connection:
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Immediately after the compressor starts, it may stop
due to "abnormally low speed" active error, etc.
The compressor may continue to operate normally,
but the power-factor will decrease, the operation
current will increase, and the overcurrent breaker
of the household power board will probably activate.
In case of active module faulty or defective contact:
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Although the compressor continues to operate
normally, the power-factor will decrease, the
operation current will increase, and the overcurrent
breaker of the household power board will probably
activate.
< Reference >
If diode bridge 1 is faulty, the compressor may stop
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due to "lp", "anbormally low speed", etc. immediately
after it starts, or it may not operate at all because
no DC voltage is generated between the positive e
and negative d terminals.
If diode bridge (D25VB60) is faulty, be aware that
the 25A fuse might also have blown.
If diode bridge (DS) is faulty, DC voltage may be
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not generated and the compressor may not operate
at all. Also, be aware that the 3A fuse might have
blown.
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