Hitachi RAF-25NH5 Instructions De Service page 262

4. P.W.B. Power Supply Circuit (Switching Power Circuit)
Ｔ Ｅ Ｒ Ｍ Ｉ Ｎ Ａ Ｌ
Ｂ Ｏ Ａ Ｒ Ｄ
２ ５ ＡＦ Ｕ Ｓ Ｅ
Ｌ
Ｂ Ｌ Ｋ
ＶＡ Ｒ Ｉ Ｓ Ｔ Ｏ Ｒ １
ＳＵＲＧ ＥＡＢＳＯＲＢ Ｅ Ｒ
ＶＡＲ Ｉ ＳＴＯＲ２
Ｎ ＷＨ Ｔ
Ｇ Ｒ Ｎ ３
Ｌ ０ ０ １
Cautions!
If it miss connections,
protection will work and
35V will not be outputted.
Indoor unit 1
Indoor unit 2
Indoor unit 3
Indoor unit 4
Terminal board
RAM-80QH5 has [SWITCHING POWER SUPPLY CIRCUIT FOR OUTDOOR CONTROL P.W.B.] (the circuit is in charge of outdoor
control power supply entirely) on their control P.W.B. RAM-80QH5 has [SWITCHING POWER SUPPLY CIRCUIT FOR INDOOR
UNIT] (the circuit generates 35V power supply for the indoor units of 4 rooms (3 rooms in case of 3 rooms multi) and 12V, 5V, for
electric expansion valve control on their SW-D- P.W.B. with 2-circuit.)
The functions of switching power circuit, input DC approx. 325V, which was rectificated by the diode bridge DB1, into the primary.
Switch the control IC on and off at high speed to generate the voltage in the switching transformer primary winding. Transmit the
voltage to the secondary winding through the transformer core. The voltage is generated at each secondary output corresponding to
each winding.
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Ｒ Ｅ Ａ Ｃ Ｔ Ｏ ＲＣ
Ｂ Ｌ Ｕ
Ｂ Ｌ Ｕ
Ｙ Ｅ Ｌ Ｙ Ｅ Ｌ
（Ｓ Ｐ Ｉ Ｒ Ａ Ｌ）
（Ｓ Ｐ Ｉ Ｒ Ａ Ｌ）
Ｎ Ｏ Ｉ Ｓ Ｅ
Ｐ ＯＷ Ｅ ＲＲ Ｅ Ｌ Ａ ＹＡ
Ｆ Ｉ Ｌ Ｔ Ｅ ＲＣ Ｏ Ｉ Ｌ １
Ｒ ０ ０ ２
Ｃ Ｔ −Ａ
Ｌ ０ ０ ４
Ｖ Ａ Ｒ Ｉ Ｓ Ｔ Ｏ Ｒ ３
Ｐ ＯＷ Ｅ ＲＲ Ｅ Ｌ Ａ ＹＢ
Ｒ ０ ０ ３
Ｒ ０ ０ ４
Ｌ ０ ０ ６
Ｌ ０ ０ ５
Ｃ Ｔ −Ｂ
１
Diode bridge
SW power supply for outdoor
control P.W.B.
12V-A, 12V-B, 5V-A, 5V-B
17V-A, 17V-B, -5V
Ｃ １
Ｄ １
The I/F circuit for unit 1
Ｃ ２
Ｄ ２ The I/F circuit for unit 2
Ｃ ３
Ｄ ３
The I/F circuit for unit 3
Ｃ ４
Ｄ ４
The I/F circuit for unit 4
Fig. 4-1 Function of P.W.B. Power Supply Circuit
- 292 -
Ｉ Ｎ Ｒ Ｕ Ｓ Ｈ
Ｐ Ｒ Ｅ Ｖ Ｅ Ｎ Ｔ Ｉ Ｏ Ｎ
Ｒ Ｅ Ｌ Ａ ＹＡ
Ｉ Ｎ Ｒ Ｕ Ｓ Ｈ
Ｐ Ｒ Ｅ Ｖ Ｅ Ｎ Ｔ Ｉ Ｏ Ｎ
Ｒ Ｅ Ｌ Ａ Ｙ Ｂ
ＳＷ−Ｄ
３ Ａ Ｆ Ｕ Ｓ Ｅ
-
＋
P.W.B.
＋
Ｃ ２ ０ １
SW power supply
for unit 3 & unit 4.
(35V-B BEN5V-B)
(BEN12V-B)
SW power supply
for unit 1 & unit 2.
(35V-A BEN5V-A)
(BEN12V-A)