Electrical Data - Pentair PVM Serie Instrucciones De Funcionamiento

EN
ORIGINAL INSTRUCTION
4.3 MINIMUM INLET PRESSURE-NPSH
To avoid cavitation, make sure that there is a minimum pressure on the suction side of the pump.
• NPSHA: Net Positive Suction Head
Available
• The net positive suction head available
is a function of the pump suction
system.
• NPSHR: Net Positive Suction Head
Required
• The net positive suction head required
is a function of the pump design at
the operating point on the pump
performance curve.
WARNING
Stop operation of the pump if cavitation occurs. Cavitation will cause pump damage and the resultant damage is not subject
to warranty
4.4 MINIMUM NOMINAL FLOW RATE
To prevent overheating of the internal pump components, the pump should not be used at flows below the minimum flow rate.
WARNING
Do not run the pump against a closed discharge valve for longer than a few seconds.
The curve below shows the minimum flow rate required as a percentage of the pump nominal flow rate in relation to the liquid tempe-
rature

4.5 ELECTRICAL DATA

See the motor nameplate.
WARNING
Make sure that the supply voltages, phase and frequencies correspond to the motor specifications.
4.6 NUMBER OF STARTS PER HOUR
Motors up to and including 4 kW: Maximum 100 starts per hour. Motors of 5.5 kW and up: Maximum 40 starts per hour..
WARNING
If you use another brand of motor then check the manufacturer' s instructions for the maximum frequency of starts.
4
• NPSHA=Ha-Hs-Hf-Hv-Hst (in meters
head)
• Ha: Barometric pressure.(That can be
set to 10.2 m.)
• Hs: Suction lift
• Hf: Friction loss in suction pipe
• Hv = KT+KH: Vapor pressure
• KT: Pressure reduction due to liquid
temperature.
• KH: Pressure reduction due to
elevation above sea level.
• If the liquid is water, refer to the table
below to determine the values of KT
and KH.
• Hst: Safety margin. (minimum: 0.5
meters head)
• NPSHA > NPSHR: Pump running will
be fine.
• NPSHA < NPSHR: The pump will be dry
running or cavitating.