Lorentz PS200 Instructions For Installation Operation Service page 65

Glossary of Solar Electricity and Water Pumping continued
Pump Jack - A deep well piston pump. The
piston and cylinder is submerged in the well
water and actuated by a rod inside the drop
pipe, powered by a motor at the surface. This
is an old-fashioned system that is still used for
extremely deep wells, including solar pumps
as deep as 1000 feet.
Self-Priming Pump - See priming.
Submersible Pump - A motor/pump combi-
nation designed to be placed entirely below
the water surface.
Surface Pump - A pump that is not sub-
mersible. It must be placed no more than
about 20 ft. above the surface of the water in
the well. See priming. (Exception: see jet
pump)
Solar Pump Components
DC Motor, Brush-Type - The traditional DC
motor, in which small carbon blocks called
"brushes" conduct current into the spinning
portion of the motor. They are used in most
solar surface pumps and in some low-power
solar submersibles. The motor chamber must
be filled with air and perfectly sealed from
moisture. Brushes naturally wear down after
years of use, and must be replaced periodi-
cally.
DC Motor, Brushless - High-technology
motor used in more advanced solar
submersibles. An electronic system is used to
precisely alternate the current, causing the
motor to spin. See three-phase AC. A sub-
mersible brushless motor is filled with water
and requires no maintenance.
DC Motor, Permanent Magnet - All DC
solar pumps use this type of motor in some
form. Being a variable speed motor by
nature, reduced voltage (in low sun) produces
proportionally reduced speed, and causes no
harm to the motor. Contrast: induction motor
Induction Motor (AC) - The type of electric
motor used in conventional single-phase AC
water pumps. It requires a high surge of
current to start, and a stable voltage supply,
making it relatively expensive to run from by
solar power. See Inverter.
Linear Current Booster (LCB) - An elec-
tronic device which varies the voltage and
current of a PV array to match the needs of an
array-direct pump, especially a positive
displacement pump. It allows the pump to
start and to run under low sun conditions
without stalling. Electrical analogy: variable
transformer. Mechanical analogy: automatic
transmission. Also called pump controller.
See pump controller .
Maximum Power Point Tracking (MPPT) -
An added refinement in some linear current
boosters, in which the input voltage tracks the
variations of the output voltage of the PV
array to draw the most possible solar power
under varying conditions of temperature, solar
intensity and load.
Pump Controller - An electronic device that
controls or processes the power to a pump. It
may perform any of the following functions:
stopping and starting the pump; protection
from overload; DC-to-AC conversion; voltage
conversion; power matching (see linear
current booster). It may also have provisions
for low-water shutoff and full-tank shutoff
devices, and status indicators.
Water Well Components
Borehole - Synonym for drilled well, espe-
cially outside of North America.
Casing - Plastic or steel tube that is perma-
nently inserted in the well after drilling. Its
size is specified according to its inside
diameter.
Cable Splice - A joint in electrical cable. A
submersible splice is protected by a water-
tight seal.
Drop Pipe - The pipe that carries water from
a pump in a well, up to the surface. It also
supports the pump.
Perforations - Slits cut into the well casing
to allow groundwater to enter. May be located
at more than one level, to coincide with water-
bearing strata in the earth.
Pitless Adapter - A special pipe fitting that
fits on a well casing, below ground. It lets the
pipe pass horizontally through the casing so
that no pipe is exposed above ground where it
could freeze. The pump may be installed and
removed without further need to dig around
the casing. This is done by using a 1"
threaded pipe as a handle.
Safety Rope - Rope used to secure the
pump in case of pipe breakage.
Submersible Cable - Electrical cable
designed for in-well submersion. Conductor
sizing is specified in square millimeters, or (in
North America) by American Wire Gauge
(AWG) in which a higher number indicates
smaller wire. It is connected to a pump by a
cable splice.
65