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OPERATION DESCRIPTION
SETS WITH VARIABLE-SPEED MOTORS AND PRESSURE TRANSDUCER CONTROL
The starting and stopping of the pumps are determined based on the pressure values set on the controller.
Each frequency converter is connected to a pressure transducer.
The controllers exchange information with each other and provide for cyclic changeover.
The figure shows the operating mode of a two-pump booster set
(Typical Field Set).
• On demand, water is drawn from the tank.
• When the pressure drops belows the PS setting the first pump
starts and the speed is adjusted to maintain a costant pressure as
demand increases.
• If the water consumption increases and the pump reaches
maximum speed, the second pump starts and the speed is adjusted
to maintain constant pressure.
• When demand decreases, the speed is reduced until minimum
speed is reached and one of the pumps are switched off.
• If consumption keeps decreasing the pump slows down, fills the
tank and stops at the pressure setting.
PS
Pressure
Flow
Figure 3
Pmax
Duplex
OPERATING CHARACTERISTICS AND LIMITS
Type of pumped liquids Water containing no gas or corrosive and/or aggressive substances
Fluid temperature Above 0° F to 180° F, Pressure transducer limited
Ambient temperature Above 0° F to 104° F, VFD/Display, keep away from direct sun
Maximum operating pressure 360 PSI (Pump without transducer)
Minimum inlet pressure According to NPSH curve and losses, with a minimum margin of 0.5 m
Maximum inlet pressure
The inlet pressure added to the pressure of the pump at zero flow must be lower
than the maximum operating pressure of the set (suction and discharge).
Installation
Indoors/outdoors, protected from the direct sun. Away from heat sources. Maximum
elevation 3300 feet ASL. Maximum humidity 50% without condensation.
Hourly starts
Maximum 60 up to 10 HP. Above 10 HP and up to 50 HP, maximum 40 starts per
hour. Variable speed drive starts.
Sound emission See table
* Note: For higher temperature it is necessary to use special materials (only on request).
NOISE EMISSION LEVELS
60 Hz 3500 RPM LpA (dB ±4)
HP NEMA Motor Frame PHV
1 56 < 70
2 56 < 70
3 56 < 70
5 145 < 70
7½ 182-184 < 70
10 215 < 70
15 254 73
20 256 75
25 284 75
30 284 75
* Note: Adjusted from 50 Hz data, may vary.