Pump Control Assessed Learning Exam

Video 1--Introduction

Question 1 *

Motors are a common way to power pumps. Four technologies mentioned to protect motors are:

Thermal overloads, contactors, soft starters, variable frequency drives
Relays, fuses, soft starters, variable frequency drives
Enclosures, heat sinks, contactors, soft starters
Circuit breakers, enclosures, thermal overloads, contactors
Question 2 *

Which best describes a contactor’s basic functions, as explained?

Accurately positions motor, in line with pump linkages, to reduce mechanical wear
Gradual start-up, jam protection, ground-fault protection, and, in larger units, voltage and power monitoring
On/off, protection from thermal overload and phase loss, jam protection, ground-fault protection, and, in larger units, voltage and power monitoring and remote monitoring via an industrial network
Variable to rapid start-up, jam protection, ground-fault protection, and, in larger units, voltage and remote monitoring
Question 3 *

Which best describes a soft starter’s basic functions, as explained?

Same as contactor, plus it can vary the motor speed.
Same as variable frequency drive, and it can ramp up or ramp down rather than starting across the line.
Same as thermal overload, plus it controls motor speed.
Same as contactor, plus it can ramp up or ramp down rather than starting across the line.
Question 4 *

To simplify the system and create energy savings, which of the following can a variable speed drive eliminate, according to the video?

Gears, motors, pumps, valves
Gears and louvers
Belts, fans, and valves
A and B
B and C
Question 5 *

As explained, for remote monitoring, industrial networks can connect to:

Soft starters
Variable frequency drives
All of the above
A and C

Video 2--Pump Examples; Sense and Predict Failures

Question 1 *

Pumps shown on the workbench, as described, were designed for:

Gasoline, fire protection, coal slurry, olive oil
Sump pump, well pump, lubrication pump, sewer pump
Sump pump, fire protection, liquefied natural gas, sewer pump
None of the above
All of the above
Question 2 *

According to the video, motors can:

Be located inside the same housing as the pump
Connect to a pump via a C-face connection [Type C Face is a NEMA standard connection;
Connect with a Lovejoy connector between a motor shaft and pump
All of the above
B and C
Question 3 *

Contactors, soft starters, and drives, according to the video, can:

Sense current and power of a motor
Look for irregular patterns
Provide an alarm
Trip the motor to take it offline
All the above
Question 4 *

The video suggests that ways to reduce mechanical stress on a system include:

Take an early lunch
Use a soft starter, to ramp up slowly and avoid high-inrush current and rapid start
Sense and monitor when motor load increases without reason to anticipate failure before it happens
Use lubrication pumps in explosion-proof areas
B and C

Video 3--Different Methods

Question 1 *

In the video, a float switch on a sump pump, a timer or dial-based controls on a washer, and a temperature switch on a refrigerator or air conditioner were examples of:

Simple on/off controls
Proportional-integral-derivative (PID) controls
Explosion-proof controls
All of the above
B and C
Question 2 *

For small horsepower motor-pump combinations, just a switch can handle the current, but for larger horsepower applications, the video suggested:

Get a larger shovel
Contactors, smart contactors, smart starters, and drives offer greater control and system protection
Create a safety zone and controlling access
An overload relay is enough control and protection for all applications
C and D

Video 4--Smart Contactors

Question 1 *

Contactors and soft starters are available in a variety of units offering basic thermal protection to advanced solid-state capabilities. Sizing guidance comes from standards organizations mentioned in the video. These are:

NEMA (National Electrical Manufacturers Association) and UL (Underwriters Laboratories Inc.), by horsepower;
IEC (International Electrotechnical Commission) by FLA full-load amps, to correspond to an ac rating on the device;
UL (Underwriters Laboratories Inc.) by motor frame size;
A and B
B and C
Question 2 *

Solid-state electronics provide modern overload protection and additional features including ground-fault current monitoring. Thermal overloads provide more traditional overload protection, according to the video, by:

Integrating circuit breakers
Including ground-fault sensing devices
Variable frequency drives
Running current through metal, also called a bimetallic thermal overload
A and B
Question 3 *

According to the diagram and graphs shown:

A backward S in each line between the contactor and motor represents a thermal or bimetallic relay, which can be replaced with solid-state electronics.
Current monitoring is not linear, which makes it difficult to detect changes under small load conditions.
Power is linear with percentage of load, so it is easier to see load changes and system inefficiencies.
All of the above
B and C
Question 4 *

Choose the correct statement, according to the video.

Contactors offer ramp-up and speed control, eliminating the need for a soft starter or drive.
Contactors offer on-off capabilities and power protection appropriate for many applications.
Starting a 250 hp motor with a contactor instead of soft starter or drive probably won’t create a spike in peak demand and extra charges by the local electric utility.
A and B
B and C

Video 5--Soft Starters or Drives?

Question 1 *

Soft starters are also called soft starter or solid-state reduced voltage starters. Which was not another common name mentioned for a variable frequency drive (VFD)?

Adjustable speed drive (AFD)
Variable speed drive (VSD)
Silicon-controlled rectifier (SCR)
Question 2 *

Gradual start of a large motor-pump system using a soft starter or drive, instead of full-on, can:

Reduce water hammer and pipe stress
Reduce stress on motor-pump couplings, valve and pump seals, and components
Reduce large in-rush currents and keep lights from dimming
Eliminate related peak demand charges
Do all of the above
Question 3 *

According to the video:

A soft starter can include a bypass contactor and can remove the silicon-controlled rectifier (SCR) from the circuit once the motor gets up to speed, then the motor runs across the line.
A soft starter can include phase loss protection, phase unbalance protection, and jam and stall protection for the pumping industry.
Drives provide ramp-up and ramp-down functionality of soft starters, and can vary speed as needed to change pump output.
All of the above
A and B

Video 6--Soft Starters

Question 1 *

Soft starters come in various styles, depending on horsepower and application needs, according to the video. Select the fictional fourth, which does not describe soft starter capabilities.

Soft controller without overload. Thermal overload protection can be added in the panel and connected if needed.
Valve throttling capability, which runs a pump at a lower constant speed to replace the need for a valve
Soft starter with solid-state electronic overload, which can be network enabled
Soft starter with thermal overload protection, jam and stall protection, phase loss and phase unbalance protection
Question 2 *

A side benefit to soft starter retrofit might be scrap metal reclamation. An old two-speed, 250 hp soft starter might have a 3 ft x 6 ft footprint incorporating two large copper transformers, the video said. It can be replaced with one that can be remotely monitored and (as of 2012) is about the size of:

A two-drawer file cabinet
A small bag of groceries
A brick
A smartphone
A or D, depending on desired functions
Question 3 *

Two main reasons to use a soft starter are to reduce electrical stresses and reduce mechanical stresses, the video says, plus an upper current limit setting can avoid peak-demand charges. The graph of time versus current shows how:

Some motors can draw eight to twelve times full load amps (FLA) when starting without a soft starter, and cut that in half to four to six FLA by using a soft starter.
Using a soft starter can extend peak demand charges into two 15-minute periods, thus lowering the overall electric bill.
The “X” on the soft starter graph dotted line represents the point at which the motor is up to speed and the SCR bypass kicks in, limiting voltage and heat loss.
A and B
A and C
Question 4 *

The water hammer video clip shows:

Pipe damage that can occur when a motor instantly drives a pump to full speed
Slower motor start, avoiding motor-pump linkage stresses
Soft stopping a motor and pump compared to an instant shutdown
A and B
None of the above

Video 7--Variable Speed Drives

Question 1 *

Variable-speed drives (VFDs):

Are “one size fit all”
Generally offer the capabilities of contactors and soft starters
Can accept control commands from other controllers and can act as a controller vary motor-pump speed itself
Can include feature sets specific to various applications, such as pumping, heating ventilation, and air conditioning (HVAC), and other applications.
B, C, and D
Question 2 *

VFD graphics in the video show:

Line (building) voltage converts ac voltage to dc, and capacitors store dc voltage to compensate for sags or swells
Inverter section, “where the magic happens,” has insulated gate bipolar transistors (IGBTs), which switch on and off at up to 16,000 cycles per second, simulating an ac sin wave using pulse width modulation and delivering a variable frequency output.
How a VFD connects to pumps and valves
All of the above
A and B
Question 3 *

Choose which of the following was not true or not discussed in the VFD for pumps video.

VFD features such as keypad, start and stop buttons, up/down arrows, I/O (inputs and outputs) connections, speed presets, various networking options
Rule of thumb: Reducing the speed of the pump by 20% saves about 20% maintenance costs.
Example: If pressure drops in building piping because everyone returns from lunch and is flushing toilets and washing hands, a pressure transducer could send a signal to a drive to actuate a pump-motor combination to keep pressure in pipes at a constant 60 psi. The drive uses a PID (proportional-integral-derivative) control loop where receive a feedback signal from a transducer and make a decision.
Drive helps the motor-pump system use only the energy that’s needed, rather than using a valve to control [limit] the flow of water through a system.
Rule of thumb: Reducing the speed of the pump by 20% actually saves 50% in energy use.

Video 8--Review of Methods, Benefits

Question 1 *

In pump and other applications, for connected motors:

Contactors provide on-off capability and overload protection
Soft starters add gradual on and off functions
Variable frequency drives (VFDs) can vary speed of the motor-pump combination, providing just the speed needed
All of the above
A and C
Question 2 *

Energy savings are realized with:

Contactors, providing thermal protection, saving assets before early wear or failures
Soft starters by reducing system stresses and limiting demand charges
VFDs that control motor speed to use just the energy needed
VFDs that also can reduce waste by eliminating multiple on-off cycles. Running at a constant slower speed can reduce system wear-and-tear and pump only what’s needed when it’s needed.
All of the above