Discharge Procedure And How To Cut Off Power To Power Circuit - Hitachi RAM-55QH5 Service Manual

Discharge procedure and how to cut off power to power circuit

Caution
DANGER
Voltage of about 360V is charged at both ends of smoothing capacitor 330 µ F x 3.
G
High voltage (DC 360V) is also charged at screw and terminal sections of system power module.
G
During continuity check of each circuit of electrical parts in outdoor unit is performed, to prevent
G
secondary trouble, disconnect red/gray wire connected to system power module (SPM) from diode stack.
(Also be sure to perform discharging of smoothing capacitor.)
1. Disconnect power plug.
2. Wait for 10 minutes or more after power is turned off and then remove electrical parts box lid. As shown below.
Apply soldering iron of 30-75W for 15 seconds or more to P1 and N1 black/white lead receptacles on system
power module to discharge voltage from smoothing capacitor.
Do not loosen or remove screws of system power module: If screw is loose, voltage will not be discharged.
3. Before operation check of each part of circuit, remove receptacle of red/gray lead connected to system power
modelu from diodde stack.
Screws of system power module are live parts: Do not touch
them. Screw tightening torque and method are strictly specified.
When the screw is loosened or removed once, be sure to
tighten according to the procedure shown on the right, with
tightening torque of 0.8±0.2N•m.
SMOOTHING
SPM (SYSTEM POWER MODULE)
CAPACITOR
REACTOR
DIODE STACK
SERVICE SWITCH
‚ O E E E E E‚ `
CONTROL P.W.B.
SELF-DIAGNOSIS LAMPS
– 107 –
Do not use soldering iron with
transformer: Doing so will blow thermal
fuse inside transformer.
As shown left, apply soldering iron to metal
parts (receptacles) in sleeve corresponding
to P and N1 terminals of system power
module.
No.2
2P TERMINAL BOARD
SWITCHING
POWER P.W.B.
No.3 No.4 No.5
No.1 No.7 No.6