Hitachi RAF-25NH5 Instructions De Service page 266

2) Switching power supply for indoor unit
Fig. 4-3 shows the switching power supply circuit for the indoor units.
3A, fuse
Input voltage after
rectification, approx.
325V DC
※
It is supplied via
CN1 from control
P.W.B.
The switching power supply circuit consists 2 circuits , and is carried on the SW-D-P.W.B.
The circuit for A cycle generates 35V of the power supply voltage for the indoor unit 1¥ 2, and 12V and 5V for the drive of
electric expansion valve. Similarly . the circuit for B cycle generates 35V of the power supply voltage for the indoor unit 3 ¥ 4,
and 12V and 5V for the drive of B cycle electric expansion valve. The voltage specification of each output is in fig . 4-2 below.
Fig . 4-2 Voltage specification.
Output name
35 V Ð A
BEN 12V Ð A
BEN 5V Ð A
35V Ð B
BEN 12V Ð B
BEN 5V Ð B
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SW transformer 3
Fig. 4-3 Switching power supply circuit for indoor unit
Output specification Main load circuit
35 ± 2.5) V
Indoor unit 1 ¥ 2, Reversing valve for A cycle
12 ± 2.0) V
Electric expansion valve 1 ¥ 2 for A cycle
5 ± 0.5) V
Control circuit for electric expansion valve of A cycle
35 ± 2.5) V
Indoor unit 3 ¥ 4 only unit 3 operates for 3 rooms)
12 ± 2.0) V
Electric expansion valve 1 ¥ 2 for B cycle
5 ± 0.5) V
Control circuit for electric expansion valve of B cycle
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SW transformer 2
A cycle
B cycle