146
DC Inverter Multi
VRF Service Manual
3.2.4 Inspection of Electrical System
1) Check if there is any electromagnetic interference, mill dust and acid and alkaline gas around the units.
a. Power supply of the units can’t work with equipments with inverter or close to the equipment with strong
eletromagnetic interference. If there is any electromagnetic interference, make record in time, and if the situation gets
worse, the installation site must be relocated or corresponding measures must be taken.
b. Prevent acid or alkaline gas or liquid from corroding cables of the units.
2) Inspection of Appearance of Power Cord
Inspect if power cords of units are installed according to requirements of manufacturer, if the wire is firmly
connected with wiring terminal and if there is any conducting wire exposed in other joints of the power cords.
Connecting wire
inside the unit
Connecting wire
inside the unit
Connecting wire
inside the unit
Patch
board
Patch
board
Patch
board
Fixed mode of
presser bit
Fixed mode of
inverted U shaped
External
power wire
External
power wire
External
power wire
Exposed
conducting
wire
Right
Right
Wrong
3) Inspection of Power Supply Capacity of the Units
Due to the working current changes greatly under different conditions which is much more than rated current, the
electric network is unstable and power factor decreases, the capacity of power supply shall be 1.5~1.8 times of rated power.
4) Selection and Usage Mode of Air Switch and Fuse-link
a. For commercial air conditioners, independent air switch, fuse-link and other similar components must be installed,
the selection and usage mode of which shall be proper.
Note:
a1.Air switch can be protection for overload and short circuit. The ability of breaking current and response speed is
not as good as fuse-link but it can be manually reset after it is operated.
a2.Fuse-link just can be protection for short circuit of the units. Its ability of breaking current and response speed are
good but it shall be replaced after it is operated.
b.The selection of air switch can refer to rated current of the complete unit, 2.25 times of which shall be close to the
current of air switch.
5) Inspection of Components inside the Eelectric Box ( De-energization )
Firstly, inspect if the components inside the electric box dropped off during transportation and then check if there is
any loose components or wiring. For huge units, the terminal of patch board and wiring terminal shall be screwed up again
and after the units have been running for 2 months, screw them once again. Due to the auxiliary contact of AC contactor
has been debugged in factory, it can’be disassembled.
6) Cautions of Laying the Power Cord
The trunking and ame-retarded PVC pipe shall be used when laying the power cord and for huge-sized power cord,
the cable supporting sytem shall be used. Don’t expose the power cord under sunshine or rain.
a. Relationship of Power, Current and Width of Cable
Selection of Cable
Category: Rubber, PVC
Width of Cable: Firstly, gure out the distance between electric cabinet and the unit and then the total length of cable.
Finally, check the Ω/km according to the model of the cable to determine the width of cable.
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