Need an idea for a cool lab project

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Minuteman

Minuteman

Senior Member
Location
The Sooner Nation
Okay, so I'm teaching 2nd year apprentices, and I need to get them into the lab sometime. Not just to break up the monotony, but for GP.

This week we will discuss conductors and OCP. Anyone have a cool idea how we can demonstrate OCP properties? I have 18 students in second year (all employed in the trade) and would like to break up into 6 groups. Thanks in advance.
 
iMuse97

iMuse97

Senior Member
Location
Chicagoland
break open a few 20A CBs and ask them how many amps that breaker can hold before it trips.

run two 1500 watt space heaters on another 20A CB and see how long it actually goes.

Then have them explain to you how this happened, and why they breaker held for as long as it did, and why it tripped when it finally did.
 
Minuteman

Minuteman

Senior Member
Location
The Sooner Nation
iMuse97 said:
break open a few 20A CBs and ask them how many amps that breaker can hold before it trips.

run two 1500 watt space heaters on another 20A CB and see how long it actually goes.

Then have them explain to you how this happened, and why they breaker held for as long as it did, and why it tripped when it finally did.
Click to expand...

Great idea! I could also use a QO, GE, FPE, Zinsco and compare the differences. :grin:
 
S

SiddMartin

Senior Member
Location
PA
maybe throw in a sin. pole switch to dead short it and trip the breaker, not sure on liability if you can do that. And also you would have to wear PPE and all that Jazz..... maybe not a good idea?<>?:-?


oh, i see that you did say OCP,... whoops
 
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H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Minuteman said:
Okay, so I'm teaching 2nd year apprentices, and I need to get them into the lab sometime. Not just to break up the monotony, but for GP.

This week we will discuss conductors and OCP. Anyone have a cool idea how we can demonstrate OCP properties? I have 18 students in second year (all employed in the trade) and would like to break up into 6 groups. Thanks in advance.
Click to expand...

Using small gage wire is usually a great eye opener when it lights up (I wouldn't use coated wire, no need to set off the fire alarms:D).

apply resistance theory to long runs, where it might not operate a OCPD fast enough to protect a conductor, show how a ground rod in most cases cant open a OCPD, wow with all the discussions here, just look around for the myth buster threads and build upon it.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
For Fifteen minutes, you can bring out the big floor buffer turn it on and
hear the Cap turn off... :grin:

Radio Shack has some peg board books of little devices that can be built.

get two phone (older) handsets and place a 9 volt battery inline on one, and get to talk through wires...

Break out a rheostat (NOUN: A continuously variable electrical resistor used to regulate current. ) put that on line to something and play with the it...

Break out an motor (kept cold) and have them ohm and take reading in a preventative maintain routuine. Megger well... you can explain that :)

slowly heat a wire with current on it, noting results.( U can use a single blower on it)

off | stop| on... wire that and then add momentary switch.
Maybe, maybe not...

Get a magnet, gauss meter and wire, explain Gauss Law, the old magnet under paper with metal flakes, always a crowd pleaser.

You could go into orbital body's and the law of attraction Here that link is corny but its will explain it if you follow the links.

search all of newtons laws: But wait you say I don't need no Newton... oh

Newton's law of gravitation resembles Coulomb's law of electrical forces, which is used to calculate the magnitude of electrical force between two charged bodies. Both are inverse-square laws, in which force is inversely proportional to the square of the distance between the bodies. Coulomb's Law has the product of two charges in place of the product of the masses, and the electrostatic constant in place of the gravitational constant.

Newton
b65000f8f887a68545ce63eb1cada232.png

F is the magnitude of the gravitational force between the two point masses,
G is the gravitational constant,
m1 is the mass of the first point mass,
m2 is the mass of the second point mass, and
r is the distance between the two point masses.

verses

Coulomb's
u8l3b1.gif

Q1 represents the quantity of charge on object 1 (in Coulombs),
Q2 represents the quantity of charge on object 2 (in Coulombs),
and d represents the distance of separation between the two objects (in meters). The symbol k is a proportionality constant known as the Coulomb's law constant. The value of this constant is dependent upon the medium that the charged objects are immersed in.

Pure water experiment with Salts and and lemons and organges... citrus, measure for...

Explain polorized Glasses! Explain sun light as it goes forward.
Explain the Electromagic Spectrum...

Explain why a crystal displays a rainbow, back to Newton.

explain or experiment with Newton's Laws and the Electrical Force
Chapter three of electrical forces
 
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cadpoint

cadpoint

Senior Member
Location
Durham, NC
If you couldn't tell from other post a lite sprinkle of physics might well be in order, Just MO...

You have to take them into some of the aspects of why things work, they already know the work side,
you got to show them the wow, moments :D

Explain metal(s) and conductors and insulator and isolator properties.

Explain lugs, terminations w/code ref's - Torque properties defined explain correct practices.

Explain Bolt Thread Properties - materials properties of and bolt head labeling.

Breakers where mentioned, drill one open, do and overview on spring mechanical properties, have them measure the contact area/to amp wire sizes. Type of breakers, write away for broken merchandise and/or supply house or manufacture/ explain your situation/ and see the hosts site for instructors.

Explain breakers types, explain fuses, types of fuses, note properties types.
Explain a thermostat, note dual properties of old style.

Explain ASTM, ANSI, UL, NFPA, AHJ

Sorry it’s not so much group based stuff, but every time I read about teaching… well …

Enjoy

PS: You know you got the students when they don't want to leave or stay after to ask more questions! ;)
 
K

KP2

Senior Member
Location
New Milford, CT
O.L project

O.L project

We set up a load of 34 amps and a GE 15 amp breaker held for over 30 minutes. The cord was hot and the breaker hummed but at 36 amps it only held for a few minutes. after the breaker was warm it wouldn't last that long.
We set up the project to gradually increase the load and watched an amp meter to see the difference between a spike when the entire load is turned on at once verses on gradually.
 
Sierrasparky

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
As a safety Demo.
You can show the class how you can cook a hot dog with 120v.
All you need is a 2wire cord with plug and two nails.
Most students won't realize the damage to ones person with 120 volts.
It sure makes a tasy dog!
 
SG-1

SG-1

Senior Member
Location
Ware Shoals, South Carolina
Sierrasparky said:
As a safety Demo.
You can show the class how you can cook a hot dog with 120v.
All you need is a 2wire cord with plug and two nails.
Most students won't realize the damage to ones person with 120 volts.
It sure makes a tasy dog!
Click to expand...

Throw in a circuit breaker to prove it will not save the weenie, then switch to a GFCI to show how it will. A pickle works pretty good too. Watched a U-tube video using a pickle. I would suggest going out to eat after using the pickle.
 
Sierrasparky

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
SG-1 said:
Throw in a circuit breaker to prove it will not save the weenie, then switch to a GFCI to show how it will. A pickle works pretty good too. Watched a U-tube video using a pickle. I would suggest going out to eat after using the pickle.
Click to expand...

Tell me how you trip the GFCI? do you place a ground wire around the Dog?
 
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