20
Model MW ( 2 variable speed pumps )
model
MWF 30
Maximum motor rated power (single pump) @ 400 Va.c.
kW
3.0
Maximum motor rated power (single pump) @230 V a.c.
kW
1.7
Maximum current (single pump)
A
8.0
input
Three-phase voltage
V
400 +/- 10% (230 +/- 10%)
frequency
Hz
50- 60
max nominal current
A
16.0
output
(variable speed
pump 1)
Three-phase voltage
V
400 (230)
Frequency (variable speed pump 1)
Hz
0 --> 50- 60
max nominal current
A
8.0
output
(variable speed
pump 2)
Three-phase voltage
Hz
400 (230)
Frequency (variable speed pump 2)
A
0 --> 50- 60
max nominal current
kW
8.0
Main circuit breaker nominal current
A
40
Thermal magnetic switch nominal current
A
-
Fuse module nominal current
A
10
SURGE TANK
A surge tank of minimum volume is necessary even when an inverter is used and this for two main reasons:
1.
to avoid that each small requirement of the linked unit, or a small leak, cause
repeated pumps starts.
2.
to
absorb any overpressures from the system
, due to sudden maneuvers and stops, etc.
SURGE TANK VOLUME
By using diaphragm tanks, a total tank volume, expressed in litres, of not below 10% of the single pump flow
rate, expressed in litres/ min., is quite adequate.
For example, a unit equipped with pumps with a maximum flow rate of 200 l/min (single pump) and
standard application, requires a tank with volume of:
Vt = 200 x 10% = 20 litres
The resulting value must be rounded up to the nearest size on the market.
SURGE TANK INFLATING PRESSURE
The tank must be pre-inflated, in the absence of back pressure system (no system pressure) to a pressure of
70% compared to the working pressure of the inverter
For example, a unit working at 5 bar in a standard application requires an inflating pressure of:
P tank = 5 bar x 70% = 3.5 bar
SAFETY PRESSURE SWITCH
In order to ensure that
the plant pressure never exceeds a
certain limit
, even in the case of incorrect user maneuvers, a
normal mechanical pressure switch can be connected as an
input signal (INPUT, see fig. aside).
-
Adjusting the mechanical pressure switch
to the maximum
tolerable pressure from the system
- and
programming parameter
3.5 (INPUT 1 CONFIG) or 3.6
(INPUT 2 CONFIG) to the value 2 (EXT ENABLE - menu 3
HARDWARE SETUP menu)
The inverter will be switched off by the pressure switch
whenever the safety pressure is accidentally exceeded. When
the pressure drops below the critical value, restoration is
immediate and automatic
