Metacentre DCO
Page 9
4.2 Power Supply
External Branch Circuit Protection:
A fused branch circuit protection, rated at
250Vac/20A maximum, with isolator must be
installed on the main incoming power supply,
external to the unit. The branch circuit fused
isolator must be fitted with two UL listed 250
Vac/2.0 A rated fuses, one on the live and one
on the neutral supply circuits. The fuses must
comply with UL 248-4, Class CC, Guide JDDZ
and be contained by Class CC fuse holders.
A suitable switch or circuit-break, meeting
IEC60947-1 and IEC 60947-3, must be used
as a means of disconnection. It must be
included in the building installation, in close
proximity of the equipment, and within easy
reach of the operator. It must be marked as
the disconnecting device.
E
L
N
1
2
3
4
E
L
N
E
X10
Use at least AWG 18 (maximum AWG 14)
wires for the incoming supply.
For field wiring terminals use copper
conductors rated 60 / 75°C only. Field wiring
tightening torque 1.2 Nm
A permanent earth connection to the unit’s
earth, as illustrated, must be implemented.
The AWG size of the earth connection must be
the same as the incoming supply wires.
The applied torque for fixing must be at least
1.2 Nm
The Metacentre DCO will accept any power
supply voltage between 115Vac to -
10%, 50/60Hz, 60VA; no internal adjustment or
setting change is necessary
.
4.3 Pressure Sensor Location
The system pressure sensor (P) must be
located in a position that will continuously
experience pressure that is common to the
delivery of all compressors in the system.
Generation Side Pressure Control:
1
P
P
2
System (Demand Side) Pressure Control:
1
P
2
P
1
P
2
P
P
System pressure will be lower than the set
‘generation’ pressure due to pressure
differential losses across air treatment
equipment. The nominal system pressure will
reduce as the air treatment differential
pressure increases.
Ensure each compressor is equipped with
independent excess pressure shutdown; an
increase in pressure differential across air
treatment equipment can result in excess
compressor discharge pressure.
Regular routine monitoring of pressure
differential across air treatment equipment is
recommended.
