pump performance testing

living with the lab

© 2011 LWTL Faculty Team

living with the lab

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The content of this presentation is for informational purposes only and is intended only for students attending Louisiana Tech University.

The author of this information does not make any claims as to the validity or accuracy of the information or methods presented.

The procedures demonstrated here are potentially dangerous and could result in injury or damage.

Louisiana Tech University and the State of Louisiana, their officers, employees, agents or volunteers, are not liable or responsible for any injuries, illness, damage or losses which may result from your using the materials or ideas, or from your performing the experiments or procedures depicted in this presentation.

If you do not agree, then do not view this content.

DISCLAIMER

pump testing system

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switch for DC power to pump digital scale to weigh water

water collection column

water collection bucket

12VDC power supply

container to prevent water leakage

tubing with valve to connect pump to bucket

wiring to allow connection of multimeters

terminals for pump power

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connect pump just to see if it will run

connect black leads togetherconnect red leads together

connect lower leads to pump

flip the switch to power pump very briefly just to see if it turns

don’t run pump dry

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what if your pump doesn’t run????can you hear or feel the pump try to run? yesno

you probably aren’t getting any power to the motor

• is the power supply plugged in?

• check your alligator clip connections

• is the switch on?

• if these things fail, then use your multimeter to see if you have power at the motor leads when the switch is turned on

your shaft or impeller is stuck and can’t freely rotate

• look through the clear faceplate to see if you can see the problem

• your impeller may be touching the face plate o unscrew the faceplate screws some . . . all you need

to do is to slightly compress the o-ring to prevent leaking out of the front

o get an oversized o-ring from instructor if needed o sand impeller so it is flush with the top of the pump

body to prevent contact

• the bushing may be squeezing the motor shaft too tightly → ream out the bushing with a #42 bit

• the barbed fitting may be contacting the impeller → try unscrewing the fitting a few turns

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fill your bucket to the correct level

7 inches

fill water to the bottom of the tape measure

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hook the pump up to the water supply

inlet (from water bucket)outlet

(hooked to long tube)

open valve until water flows freely through pump . . . this “primes” the pump

the pump should ALWAYS stay below the water level in the bucket

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turn the pump on and see what happens 1. if pump doesn’t pump at least one foot, then . . .

• make sure water runs freely through pump when it is off (is it primed?)• turn outlet upward and tap pump against water bucket to allow bubbles

to float out• try reversing the polarity of the motor to see if that helps• if none of these things work, you likely have an air leak

o most air leaks are at the faceplate o-ring (keep uniform gap between pump body and faceplate)

o it is also possible that you have an air leak at the bronze bushing → the small o-ring may have been pushed out

o can also have an air leak around a barbed fitting . . . did you use Teflon tape?

2. see how high the pump can pump

exit

tube

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pump testing

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• see how high your pump can pump water• measure electrical current and voltage as well as the mass of water collected at eight

or more heights (or pump heads) up to a maximum of 72 inches• generate a plot of pump head versus flow rate• generate a plot of pump efficiency versus pump head

head or height that water is pumped

(in)

electrical current needed to power pump

(A)

voltage across pump leads

(V)

length of time that water is collected

(s)

mass of water collected over 20 seconds

(g)

height 1 20

height 2 20

… height 8 (or more) 20

h = head

m = mass of water collected

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current and voltage measurement

voltage

curre

nt

voltage is measured between the + and – power leads

current is measured by “breaking a lead” and letting the current pass through the multimeter

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collect water at different heights for 20 seconds . . . and weight the water

head or height that water is pumped

(in)

electrical current needed to power pump

(A)

voltage across pump leads

(V)

length of time that water is collected

(s)

mass of water collected over 20 seconds

(g)

height 1 20

height 2 20

… height 8 (or more) 20

let water run back down pipe between

measurement

remember to zero the digital balance to account for container weight

the displayed weight is the actual weight of the water

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• Keep water away from all electrical equipment except the pump, and do your best to keep the pump motor dry.

• Don’t handle the wall adapter or other power supply with wet hands or wet feet (or when in contact with water).

• Wipe up any water that leaks onto the floor.

• Report any problems encountered to the help desk or to your instructor.

SAFETY

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cleanup• empty bucket and catch pan back in sink• mop up any water leaked or spilled on the floor• put the station back in its original configuration

individual versus team

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Group Assignment: Fabrication and testing of your pump are group assignments. The pump fabrication was completed in groups of two students, and pump testing is to be completed by groups of two to four students; two pump fabrication teams should combine to test the better of the two pumps fabricated. It is common for four students to share the same raw data from pump testing. Individual Assignment: The pump project counts as a significant percentage of your overall grade, and the work that you submit for this grade must be your own. Please be aware that the pump assignment is not a “regular” homework assignment. You are allowed to discuss your work with other students, but no direct copying of work and no sharing of computer files is allowed (such as Excel and Mathcad files); please type in the raw data collected into Excel yourself. You may share photographs that you took of your group during fabrication and testing.

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start your analysis . . .