The Submersible Wastewater Pump Association (SWPA) has
developed a Standardized Presentation Format for Pump and Motor
Characteristics for a pump or family of pumps. The required information
included in the presentation format is the minimum data needed by a specifier
or designer to adequately evaluate using a specific submersible wastewater
pump for a specific application.
By using the SWPA Standardized Presentation Format,
pump manufacturers present data in a consistent format so the designer or
specifier can make an informed comparison between different brands or types
of equipment. A major component of the presentation format is a series of
Standardized Pump/Motor Definitions developed by the Association
(see page 3). They define the terms that the data represent.
SWPA members (see the Membership Roster) may use the
Association's Logo with the designation "Approved Curve and Data
Format" in conjunction with statements that their performance
curve(s) provide a minimum number of data categories and the minimum design
information as recommended by the Association. Pump manufacturers, at their
discretion, may include additional information. SWPA assumes no responsibility
for any other manufacturer claims made relating to the pump performance curve(s)
or for the correctness of the information presented.
The following statement is to be included on any performance
curve(s) carrying the SWPA Member Logo. "SWPA Data Categories Presented --
Data on this sheet supply design information as the minimum recommended by the
Submersible Wastewater Pump Association (SWPA) and is defined in accordance
with SWPA's Standardized Definitions for Pump and Motor Characteristics. The
accuracy of the data is the responsibility of (company name)."
At the pump manufacturer’s choice, the presentation may be in
a one-page or two-page format, including a performance curve(s) and the
minimum pump and motor data design as recommended by SWPA.
Each company seeking approval to use the "Approved
Curve and Data Format" logo, is required to file a formal application
which includes a Statement of Compliance, attesting that the company’s
Chief Engineer or Technical Manager: "Has reviewed our performance
curve(s) and appropriate minimum data as prescribed by SWPA and to the best
of our ability and knowledge all sheets for which we are seeking approval to
display the SWPA Member Logo are in compliance with the SWPA recommendations
for minimum data to be included and that the data is presented as defined by
SWPA's Standardized Pump/Motor Definitions."
Each application and accompanying curve and data presentation
is reviewed by the Association’s Technical Committee to insure that the minimum
recommended data and information are included. Those that meet the minimum
requirements are then permitted to use the logo and accompanying language,
indicating conformance with the SWPA Standardized Presentation Format.
Standardized Pump/Motor Definitions
The Standardized Pump/Motor Definitions presented here
were developed by SWPA’s Technical Committee which includes knowledgeable
specialists from submersible pump and accessory companies.
Pump Hydraulic Efficiency:
Expressed as a percentage of liquid horsepower to brake horsepower over the
recommended operating range of the indicated impeller size(s).
Brake Horsepower (BHP):
The power delivered to the pump shaft under stated operating conditions of
the pump where horsepower is 550 foot/pounds per second, expressed by graph
or figured by:
BHP = (Q x H x S.G.) / (K x Eff.)
where:
K x Eff.
Q = U.S. GPM
H = Head in Feet
S.G. = 1.0
K = 3960
Eff. = Pump Hydraulic Efficiency
Motor Horsepower Rating:
The motor horsepower nameplate rating fully-loaded at the ambient temperature.
RPM:
Nominal revolutions per minute of the motor/pump rotating assembly.
GPM:
The volume delivered at the pump discharge flange expressed in gallons
per minute (GPM). Expressed on X axis of curve.
TDH:
The value or quantity used to express the energy content of the liquid
per unit height. Expressed on Y axis of curve.
Discharge Diameter:
The inside diameter of the discharge port of the pump as measured at the
integrally cast discharge flange to the pump casting (volute).
Impeller Diameter:
The concentric outside diameter as measured radially of the pump impeller.
Sphere Size:
The maximum physical diameter of a non-deformable sphere that can pass through
the pump without obstruction or interference of any kind from volute
entry port to discharge port.
Motor Characteristics:
Motor characteristics terms are as defined
by NEMA motors and generators No. MGI-1978, NEC-1990, IEEE Std. 100-1992.
Electrical Motor Terms:
A) Horsepower:
A system of rating motors whereby horsepower values are determined, for
various synchronous speeds, from the minimum value of breakdown torque that
the motor design will provide.
B) Starting Amps (Locked Rotor):
The maximum current drawn by the motor during the starting period.
C) Phase (Three-phase circuit):
A combination of circuits energized by alternating electromotive forces
which differ in phase by one-third of a cycle (120 degrees). In practice,
the phases may vary several degrees from the specified angle.
D) Hertz (HZ):
A unit of frequency equal to one cycle per second.
E) NEC Code Letter:
Motors with 60- and 50-hertz ratings shall be marked with a code
letter designating the locked-rotor kVA per horsepower on 60 hertz.
F) Voltage (Nominal):
A nominal value assigned to a circuit or system for the purpose
of conveniently designating its voltage class (as 120/240, 480Y/277, 600, etc.).
The actual voltage at which a circuit operates can vary from the nominal
within a range that permits satisfactory operation of equipment.
G) Design Letter:
A letter that is shown on the motor nameplate indicating NEMA's
classification of that motor. Classification encompasses characteristics
such as full-voltage starting, locked rotor torque, breakdown torque, and
others that determine electrical type.
H) Revolutions Per Minute (RPM):
The number of revolutions a given shaft makes in one minute's time.
I) Full Load Amps (Full load current):
The current flowing through a line terminal of a winding when rated
voltage is applied at rated frequency with rated horsepower connected load.
SWPA is... a national trade
association representing the manufacturers of submersible pumps for municipal
and industrial wastewater applications. SWPA is and has been a leader in the
wastewater pump industry since its inception. Founded in 1976, the Association’s
primary focus is on industry guidelines, education, and promotion. SWPA’s members
are the industry’s leaders: regular members are pump manufacturers; associate
members are manufacturers of components and accessory products. They supply
access doors, basins, cords and cables, control panels, electric motors, lift
station accessories, seals, stainless steel enclosures, valves, wet wells and
other component parts and accessory items to pump manufacturers and the aftermarket.
- Approved Curve and Data Format -
