Homemade Load Tester

[_HL4E_HalfLife_]

Well i finally figured out a way to make a load tester to my SS systems and this is what i came up with.

http://img74.imageshack.us/img74/1784/heatloader0lb.jpg (http://imageshack.us)

http://img74.imageshack.us/img74/192/heatloader10po.jpg (http://imageshack.us)

http://img73.imageshack.us/img73/1875/heatloader27su.jpg (http://imageshack.us)

http://img74.imageshack.us/img74/5199/heatloader37lc.jpg (http://imageshack.us)

There's 2 seperate heating coils in this load tester a 40 watt and an 80 watt coil. The only thing left to do is to polish the bottom.

[wdrzal]

Thats a good idea for starters, mabee using armature wire the insulation is much thinner allowing more wraps for higher heat load. How are you powering that ???? what is the resistance of the coils??

[_HL4E_HalfLife_]

Thats a good idea for starters, mabee using armature wire the insulation is much thinner allowing more wraps for higher heat load. How are you powering that ???? what is the resistance of the coils??

I didn't want to use armature wire because of the chance there might be a spot where the insulation got scraped off and that could cause electrical problems.

Both coils are rated for 120v AC so im gonna just put a plug on each coil and plug it in.:D

Im not sure why u want to know what the resistances are but with my meter set to x1K one coil is .354ohms and the other is .169ohms.

The coils are made to be in a fridge they are put in the drain pan to evaporate the water that comes from the freezer when in defrost.

[wdrzal]

if you just plug that in the wall your just going to have a dead short. I asked for 2 reason the above and if you know the resistance and voltage you can calculate the watts and amps.

[wdrzal]

I made a mistake he said reading were at 1K and I calulated X1

[wdrzal]

one more thing electric conductivity rises when cooled, so cooling will add to posted numbers. they where calculated at the standard 20c

[wdrzal]

But is is a good idea, the correct resistance and voltage & power supply and you may have some thing.

[wdrzal]

wait halflife I made a mistake,very sorry you set you meter at 1k not 1 give me readings set at ohms X 1

[star882]

In which case:
.169 kohms = 169 ohms
.354 kohms = 354 ohms
W=V*A, A=V/R, so W=V^2/R

120V^2 / 169 ohms = 85.207W
120V^2 / 354 ohms = 40.678W

[wdrzal]

its going to be a 1000 time worse

reading is times 1000 so you take the reading and divide for times 1

[_HL4E_HalfLife_]

Guys...Guys.. there rated for 40 watts and 80 watts it was on the packaged bag they came in. So star was pretty much right on.

[wdrzal]

That was just copper wire right? if you were on R1K thats reading times 1000 so you take reading and divide by 1000 to get rx1

[jinu117]

Very ingeniutive :) But what temp are the wires rated for? I've forgot to leave mine on numerous times -_-; Many burnt evap hold down.... -_-; I suggest maybe some kind of thermal shut off for safety :) I know I should put one on mine... i've seen it going 600c few times... oh the smell of burnt plastic...!!!!
(In your case, wire insulation could melt and hotwire each other decreasing resistance... and you know the rest)
--> Everything else was intact as heatcartridge and wires leading to it, etc are rated for much higher temp... like brazing temp... just burnt enclosure really... but it's so hard to take it off evap.

[wdrzal]

come-on fess up, what happened???? did it melt or since its high temperature insulation did the breaker just trip.

Fess up

[jinu117]

come-on fess up, what happened???? did it melt or since its high temperature insulation did the breaker just trip.

Fess up

LoL. Basically this is what happened. Mine is sitting in copper block... so copper temp keeps going up... I come back later seeing smokes in garage... open the garage door to clean... air.. (no the smell stays for few days). Basically insulation on evap will melt up (about few inches of it), mounting will melt up, One good thing is evap never gets really that hot since mounting will melt through first and lose contact from the hot thing.
After first accident I use high temp insulation fibre stuff on load tester so I don't have to deal with melted rubber basically. Plastic attached to evap, etc. No trip really as my heatcartridge is rated well over the temp it was subjected to (think 800c? Don't remember off my head). Just very unpleasant smell, grunt work cleaning off evap afterwards, resinsulationg, and much of c*ssing for how stupid I am to burn off another enclosure. So far 5 mountings... bleh and about 10 hours cleaning up stuff and relapping, etc. In fact, I finally ordered thermal cut off just now :p

[wdrzal]

I ment for half/life to fess up, whats that line about 2 birds with one stone.:lol:

[wdrzal]

jinu you got me laughing so hard it hurts.

[wdrzal]

Plug you voltage and resistance in here:


http://www.chromalox.com/technical/ohmscalculator/

[Jort]

thats why i made myself a little box for it.

it needs 12Vto run, so if the prommy or other cooling is of the loadtester brakes down too.

http://www.belgium-coolingsolutions.be/Pics/phase-change//Heatloadtester/drawing.jpg

http://www.belgium-coolingsolutions.be/Pics/phase-change//Heatloadtester/e.JPG

:)

[_HL4E_HalfLife_]

I ment for half/life to fess up, whats that line about 2 birds with one stone.:lol:

Fess up to what?? im confused:confused:

[wdrzal]

If you plugged that in you got a direct short unless you used a resistor somewhere. That wire just has high temperature insulation for around ovens and the like.

[_HL4E_HalfLife_]

If you plugged that in you got a direct short unless you used a resistor somewhere. That wire just has high temperature insulation for around ovens and the like.

No it don't, when i plug it in it slowly heats up which is what its suppose to do. As i said already there ment to be in the drain pan of a fridge to evaporate the water.
Do you think they would make a drain pan heater that would blow a breaker every time the fridge went into defrost?:stick:

[wdrzal]

did you try x1 first, if not do that

maybee got readings crossed:shrug:

[johann]

I cannot see how the heat transfer between the wires and copper could be sufficient with the rubber insulation in between.

My loadtester at 120w get very hot very fast, if its not under an evap thats cooling it burns out in a couple minutes. If you say it gets hot slowly then I doubt it will generate enough heat to simulate a real cpu.

Just my thougths

[ilkkahy]

I dont see the point in making your own resistor as they can be bought from shop with reasonable price and they also work.

Here is something from my little tester:
http://www.xtremesystems.org/forums/showpost.php?p=1347250&postcount=23
And picture:
http://koti.mbnet.fi/ilkkahy/ln2&co2%20kupit/testattavat%201%20(Small).jpg

[expansionvalve]

No it don't, when i plug it in it slowly heats up which is what its suppose to do. As i said already there ment to be in the drain pan of a fridge to evaporate the water.
Do you think they would make a drain pan heater that would blow a breaker every time the fridge went into defrost?:stick:

never heard of them being used to evaporate water, whats the point in evaporating water? all i can see happening is that the evaporate will get sucked back upto the evap coil and refreeze......

i use a very similar heater cable but we use it to keep drain pans/hoses free of ice so the the defrost water can drain out the drain hose.

just my pennys worth on this miserable Monday morning...

[_HL4E_HalfLife_]

never heard of them being used to evaporate water, whats the point in evaporating water? all i can see happening is that the evaporate will get sucked back upto the evap coil and refreeze......

i use a very similar heater cable but we use it to keep drain pans/hoses free of ice so the the defrost water can drain out the drain hose.

just my pennys worth on this miserable Monday morning...

I just spent the past 30 min typing up a reply and the friggin forum says im not logged in (which i am) and lost it all:mad: :mad: :mad: man that pisses me off big time:soap: :upset: :brick: :cussing: :censored: :mad:

[SexyMF]

I am qualified for single and three phase power. I am an electronics engineer. With all the safety talk here lately I am bemused at why all you rookies who don't even understand the very basics of electricity (how to read a meter or calculate AC/DC power) happily dispense advice to go out and attach lethal mains to a resistor. I've never seen a fuse in anybodies circuit. Or and isolating transformer, or the use of low voltage (like <50).

Also remember that resistors are rated at 25C. The resistance changes with temperature. And lets face it, -40 to +100C is a wide change. If resistance didn't change with temperature we would never have superconductors.

Your CPU wouldn't work any better at -40C if all was equal.


I think that those warming coils are short term rated (not on for long) and only need to slightly greater than 0C for defrost to work.

[SexyMF]

{inserts 2C}