System Components Flashcards
The law which states that voltage (V) is equal to current (I) times resistance (R) is known as:
a) Power of watts Law
b) Coulomb Law
c) Ohm’s Law
d) Capacitor Law
c) Ohm’s Law
In an alternating current the number of times that the current alternates per second is its: a) Power b) Current c) Frequency d) Resistance
c) Frequency
If a 110V single phase motor draws 8 amperes what is its power rating in watts?
a) 13.75 watts
b) 880 watts
c) 1.2 horsepower
d) 0.9 Kilowatts
b) 880 watts
In wastewater treatment plants the most common power source for large horsepower motors is:
a) Single phase alternating current
b) Dual phase alternating current
c) Three phase alternating current
d) Polyphase direct current
c) Three phase alternating current
The minimum distance an operator should keep from a fallen power line, an exposed underground power line or a piece of equipment in contact with a live power source is: a) 1 metre b) 2 metres unless line is sparking c) 10 metres d) 25 metres
c) 10 metres
A transformer is an electrical device used to store electrical energy to meet the initial high current demand when starting some types of electrical motor.
a) True
b) False
b) False
To control the flow rate from a positive-displacement pump, such as a progressive cavity pump or a plunger pump, the operators should do which of the following:
a) Throttle the discharge valve by closing the valve as needed to control the flow
b) Throttle the inlet by closing the suction valve as needed to control the flow
c) Adjust the speed of rotation of a progressive cavity pump or the stroke length and or speed of a plunger pump
d) Install a short length of pipe smaller in diameter than the discharge pipe to provide additional head
c) Adjust the speed of rotation of a progressive cavity pump or the stroke length and or speed of a plunger pump
Which of the following statements is true:
a) Centrifugal pumps will pump more flow when the total head increases
b) Positive displacement pumps will pump approximately the same flow, regardless of the total head
c) A vortex pump is a positive displacement pump
d) The flow from a positive displacement pump will increase significantly if the total head decreases
b) Positive displacement pumps will pump approximately the same flow, regardless of the total head
Which of the following are positive displacement pumps:
a) Vortex, air lift, pneumatic displacement
b) Peristaltic, progressive cavity, piston
c) Plunger, recessed impeller torque flow, diaphragm
d) Submersible, axial flow, split case
b) Peristaltic, progressive cavity, piston
A wear ring is used in a submersible pump to:
a) Provide the operator with a visual indication of wear due to grit and cavitation
b) Act as a spacer to take up wear on an impeller due to cavitation
c) Provide an easily replaceable and relatively inexpensive way of protecting the impeller
d) Throttle the inlet to the pump to ensure that recirculation in the volute does not occur
c) Provide an easily replaceable and relatively inexpensive way of protecting the impeller
Submersible pumps can be installed in a dry well application.
a) True
b) False
a) True
In a packed pump, the lantern ring provides openings that the operator can use to
shine a light on the shaft making visual inspection easier.
a) True
b) False
b) False
In a wastewater treatment plant valves may be used to:
a) Vary the rate of flow
b) Start or stop flow
c) Isolate components of a system
d) All of the above
d) All of the above
Which of the following type of valve is best suited for use on fluids that may contain stringy solids?
a) Gate
b) Globe
c) Plug
d) Butterfly
c) Plug
Butterfly valves are commonly used in what type of service in a wastewater treatment plant?
a) As an isolation valve on a return activated sludge pump
b) To throttle flow to a dewatering centrifuge
c) As isolation valves on a centrifugal blower
d) As an inlet valve on a primary scum pump
c) As isolation valves on a centrifugal blower
