Power Wiring; Control Wiring - SURREY Multi split Manual De Instalación, Operación Y Mantenimiento

b) Power wiring:
There are wiring openings on both sides of the ventilation module, as shown in Pictures
2. Install the wiring starting from the customer power point directly to the electric box
of the condenser unit, and then the motors of the ventilation module.
The unit supplier gauge shall be dimensioned for the sum of the maximum currents, that
is, equal to 125% of the maximum current of the bigger compressor or motor, plus 100%
of all other compressors and motors. The cables shall be 105°C class or higher.
Do not forget to install the protective conduit (grounding). The supplied voltage shall
conform to the nameplate. The voltage between phases must be balanced within 2%
imbalance and the current within 10%, with the compressor in operation. Contact your
local power supply utility to correct the improper voltage or any phase imbalance.
Voltage imbalance calculation
- Voltage imbalance (%) = Higher difference in relation
to the average voltage /average voltage
- Example: - Rated power supply
380V - 3 ph - 50Hz
- Measurements:
- Average voltage 383 + 378 + 374 = 378V
The current imbalance calculation must be made in the same way as the voltage
imbalance calculation.
The causes of the voltage imbalance may be:
* Bad contact (contactor, electric connections, loose wires, oxidized or carbonized
conduits).
* Conduits with improper gauge.
* Charge imbalance in a three-phase power supply system.
c) Control wiring:
Refer to the electric diagrams in order to perform the field connections among the units
and the selecting switch.
M A N U A L D E I N S TA L A C I Ó N , O P E R A C I Ó N Y M A N T E N I M I E N T O
AB = 383V
BC = 378V
AC = 374V
3
- Difference toward the average voltage:
AB = 383 - 378 = 5
BC = 378 - 378 = 0
AC = 378 - 374 = 4
- The biggest difference is AB = 5. Thus, the % of voltage
imbalance is:
5 x 100 = 1,32%
378
(OK)
41