NGWA CPI flashcards
NGWA CPI · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Total dynamic head
- The total head a pump must overcome: static lift plus drawdown plus discharge pressure head plus friction losses in pipe and fittings.
- Drawdown
- The drop in water level in a well from static level to the pumping level while the pump is running.
- Static water level
- The undisturbed water level in a well measured when the pump has been off long enough for the level to stabilize.
- Pumping water level
- The stabilized water level in a well while the pump is operating at a steady rate.
- Specific capacity
- Pumping rate divided by drawdown, usually expressed in gallons per minute per foot of drawdown; a declining value suggests well fouling.
- Pressure tank drawdown
- The usable volume of water a tank delivers between the pump cut-in and cut-out pressures; larger pressure spread yields more drawdown.
- Tank precharge
- The air pressure in a bladder tank, set about 2 psi below cut-in pressure with the system drained of water.
- Check valve function
- A valve that allows flow in one direction only, holding the water column in the drop pipe when the pump stops.
- Motor cooling flow
- Water passing the submersible motor at roughly 0.5 ft/s or more carries away heat; insufficient flow overheats and shortens motor life.
- Pump curve
- A graph of head versus flow for a pump; the operating point is where the pump curve intersects the system curve.
- Well yield test
- A controlled pumping test that measures rate, drawdown, and recovery to establish a safe pumping rate for the well.
- Confined aquifer
- A water-bearing layer bounded above and below by low-permeability material, which can produce water under pressure.
- Artesian well
- A well completed in a confined aquifer where the potentiometric surface rises above the aquifer top; if above land, the well flows.
- Well screen
- A slotted or perforated section of casing that admits water while holding back formation material and supporting the borehole.
- Gravel pack
- Uniformly graded gravel placed around a well screen to filter fine formation material and stabilize the borehole in fine soils.
- Annular seal
- Grout or other approved material placed between the casing and borehole wall to prevent surface contamination from moving down the annulus.
- Water table
- The upper surface of the saturated zone in an unconfined aquifer, which rises and falls with recharge and pumping.
- Recovery test
- Measurement of water level rise after pumping stops; slow recovery indicates low permeability or a damaged well.
- Ohm's law
- The relationship that voltage equals current times resistance; used to check pump circuit voltage drop and current draw.
- Full-load amps
- The current a motor draws at rated load, shown on the nameplate and used to size overload protection.
- Start capacitor
- A capacitor that boosts starting torque in a single-phase motor and is switched out once the motor reaches running speed.
- Control box
- An enclosure containing the starting capacitor and relay used with three-wire submersible pumps; two-wire pumps do not need one.
- Pressure switch
- A switch that starts the pump at cut-in pressure and stops it at cut-out pressure; worn contacts can weld and run the pump continuously.
- Three-phase reversal
- Reversing rotation of a three-phase motor by swapping any two of the three supply conductors at the starter or disconnect.
- Lockout/tagout
- The procedure of de-energizing, locking, and tagging a disconnect before servicing pump or motor circuits to prevent accidental energizing.
- Equipment grounding
- A continuous conductor bonding the pump, motor frame, and well casing to the electrical system ground to prevent shock hazard.
- Short cycling
- Rapid on-off operation of a pump, usually caused by a waterlogged tank, failed pressure switch, or leaking check valve.
- Voltage drop
- Loss of voltage along a conductor due to resistance; long pump circuits need larger wire to keep voltage at the motor within limits.
- 811 one-call
- The service called before digging or drilling so buried utilities are located and marked; work must wait the required notice period.
- Mechanic's lien
- A legal claim against property for unpaid work; contractors must follow state notice and filing deadlines to preserve the right.
- Confined space entry
- Entry into a pit or vault requires atmospheric testing, ventilation, a permit, and an attendant outside the space.
- Change order
- A written, signed amendment to a contract that documents added or deleted work, price adjustment, and schedule effect.