Cheap loadtester materials

[dejanbinladen]

bump


ok i am trying to assamble my first load tester likes jinu i have everything expect variac, so my question is, is it really needed, if the catridge heater is 350W isnt that enough ??? why do i need variac, could someone explain in short please, i am bulidng my first SS so dont be rough

[n00b 0f l337]

The Variac does what its name implies, Variable-AC.
By varying the AC voltage, you vary the load produced by the cartridge.

Right now you have 0 OR 350W as your settings.
A variac would give you 0 TO 350W as your settings.

Ebay is your friend, $40-50 for a tool that's incredibly useful is awesome.

[dejanbinladen]

The Variac does what its name implies, Variable-AC.
By varying the AC voltage, you vary the load produced by the cartridge.

Right now you have 0 OR 350W as your settings.
A variac would give you 0 TO 350W as your settings.

Ebay is your friend, $40-50 for a tool that's incredibly useful is awesome.

ok you mean if i want to tune SS to lets say 200W?!?!?!? but i want to tune it to 350W (cartridge i oredered) so do i need variac anyway ?

dont get mad i am trying hard

[n00b 0f l337]

Not mad at all, looking forward to your project log!
When tuning, 0 and max isn't really viable.
When you flip the switch to 350W it probably will throw the single stage off pretty far.
You also want to know how it works through the mid-range, and want to tune for things inbetween to check for floodback.

Without a variac, if it doesn't hold 350W, you won't know how far away you are from 350W.

[dejanbinladen]

ok i cant find anything near me, can i use light dimer ?

[n00b 0f l337]

Not really.
The dimmer will use up power and heat up drastically, and won't be accurate to measure from.
Plus will cost you about a 1/4th of the variac.

If you've got the cash to invest in building a phase setup; $40-50 for a variac shouldn't be a bad kick.

[dejanbinladen]

i ordered this should be in next week, could it replace "router speed control unit", if so, this could be the cheaper alternative to begginers like me ?!?!?
http://www.ebay.com/itm/2000W-high-p...92104727148169

[ZenEffect]

I dont see how you can get accuracy out of that thing alone. there is no guage, and you dont know if the taper is logarithmic or linear. i dont doubt that it will serve its function in reducing voltage to the heater cartridge... but how are you going to measure how many watts are being used by the heater? do you have a clamp-on meter?

[dejanbinladen]

i have mesaure tool dont worry and the catridge, only thing i dont is this "variac" and i ordered this everything else i have.
so could it work or not ?

[ZenEffect]

i have mesaure tool dont worry and the catridge, only thing i dont is this "variac" and i ordered this everything else i have.
so could it work or not ?

if you can measure load accurately, then i dont see why not. looks like its gonna get hot though, mount it on a bit of wood or something with a fan.

[dejanbinladen]

ok i got all the stuff for load tester, and today I assemble it, and when i powered it on it goes only to 136W-138W, first i thouht it may be the little variac and directly connected the catridge to power source. it stayed at 138W
One i ordered and payed for is 350W i was pissed so now i contacted the seller to send another one, so antoher month wating.

here are few pics of the build


stay tuned

[dejanbinladen]

i am lost here some help please
i put 350W directly on the wire and kilawat and it show about 138W, then i thought it could be the wrong catridge they sent me, so i ordered 250W plug it in and its also about 135W :S
today recieved 300W and it says 180w.

this is all with or without variac

is the killawatt measuring wrong or what i am lost here :S HELP

[n00b 0f l337]

You put "350W directly on the wire"...
Not sure if its phrasing or if I'm confused. But how did you manage that?

Do you mean you added a 350W load of heaters to the wire?

Are the cartridges the right voltage? You appear to be on 220V, and that chinese seller has both 110 and 220 cartridges.
Have you tested it without your little circuit? Because that is NOT a variac. And from what I can see on it, it doesn't look like it would even do anything...

Test the items one at a time. Kill a watt in to the wall. See if it can read voltage.
If it can read voltage...

Wall --> "Variac" --> Kill-a-watt

Then see what voltage the kill-a-watt reads when you adjust the "variac".
That little thing might just be a solid state FREQUENCY adjuster for small fans. The 2000W rating is certainly BS. Maybe that fuse is rated for 2000W!

[n00b 0f l337]

Okay looked at other "products" they have.
It's advertised incorrectly and is clearly JUST a thyristor. That means it is meant to adjust the amount of a given cycle that is let through.
That from my understanding, well, it won't do anything with a resistive load cartridge. It'll just show up with faulty readings, and you'll have no idea how much power is actually being used.

EDIT: Not to be blunt, but like I said earlier, get a Variac else they're really isn't another method to get these things to work. I mean, you could get a bunch of different transformer coils and use them one at a time to down/up voltage. But that's going to be more expensive then a $50 variac.

EDIT2: A thyristor is sort of a one way valve for power. But when used in AC current, that means its blocking the ALTERNATING part.
As you increase the resistor attached to the SCR (more resistance as you go down this chart), the SCR turns back on at a later point. Notice how the entire "negative" voltage "stroke" is gone.
That system may work for adjusting a motor, or a fan, but will not function for a steady resistance based load, at least from my understanding.
Chances are a kill-a-watt wouldn't have much idea what to do with that kind of signal either way.

[dejanbinladen]

thx noob

maybe i didnt explain well. i dont even use this variac, i directly plug catridge to the outlet and it low on watts. its not the variac problme cause i dont even use it yet.

on one of the catridges says 220V 250W

[n00b 0f l337]

Interesting, so even with no "variac" its a no go..
That doesn't make much sense at all I must say. Time to test another item to eliminate if its the kill-a-watt or the cartridges are all bad...

Got any other electrical devices laying about? If you put that kill-a-watt on a lamp with a 60W lightbulb or such check the reading.
Aka test other devices.

[dejanbinladen]

ok i wll try with the lamp

EDIT - i tried lamp from the bedroom its 40W bulb and wat meter says 43W so it seems its working fine, but cant believe that all the 3 catrdiges are fake :S

[n00b 0f l337]

I have some of the same ones, work absolutely fine. So now we have to identify what's wrong.
Measure the resistance across the cartridge and contact the seller for what the resistance should be.

[dejanbinladen]

i am sure you will understand the seller doesnt give a banana about my problem, i contacted for the 350w and for apologie they send me this 300w and its 180w sooo... no point IMHO

[n00b 0f l337]

Giving up doesn't do you much good either way.
Here's something you can try.

Hookup two cartridges at once in parallel. Make sure the power is additive.
Goal here is just to find the error.

[dejanbinladen]

ok thx man once again i will try that

[n00b 0f l337]

No problem.
Just seems like a strange issue.
Do you happen to also own a multimeter that can read amperage? We can test this the old fashion way and go around the kill-a-watt to isolate the issue.
It's hard for a cartridge heater to be "broken" you know what I mean?

[samsarulz]

Bump again


Hello guys. Had been reading for a while about the cartridge heaters and after some fails using some peltiers I decided to use something better, safer and reliable.

HAve asked runmc and he has lend me a hand in this matter by helping me to choose which things I need to buy:

Variac, and cartridge heaters are OK. I know where to buy both (same as runmc on Ebay and else with McMaster Cann) . Now looking for copper from OnlineMetals (thanks teyber).

Thanks in advance

[runmc]

Ask Buckeye if he'll see you his.

[samsarulz]

Ask Buckeye if he'll see you his.

Thanks again ron. I will for sure.