volt X amps X power factor = watts since the PF for resistive heating elements is ~1 Using just volts X amps = watts is ok.
140v x 2 amps = 280 watts max. for your new variac.
The 150 watt heaters are rated that @ a specific voltage & @ have a specific resistance, DetriotAc would know exactly.
Or You can measure the resistance of the cartridges ,Ohms. then the voltage the variac is putting out and plug those numbers into a ohms law calculator. that will give you the watts and amps.
Something is confusing me because when my old variac was set at 95 volts it was drawing 200 watts from the wall based off the killowat reader but if thats the case then
95volts x 6amps = 570 watts?
How does the resistance of the heat cartridges fit in again?
Your mixing numbers from the primary side(wall recepticale,variac input) and the secondary side (variac output.)
Your primary side is your line voltage,say 115 or 120 volt(this is constant) and current (amps) is only limited by wire size 14/2 or 12/2 and circuit breaker or fuse in electrical panel (15 amp for 14/2 wire) or (20 amp for 12/2 wire.)
Your Secondary side of the variac is adjustable 0 to 140 volts with a max of 2.4 amps.
I'm guessing DetriotAc wired the heating cartridges in parallel, so enter the volts from the variac output then the ohms from 1 cartridge intocalclator , this will give you wattage for 1 cartridge............then multiply X 2 for total watts
For your purposes ,it's more accurate to use numbers from the secondary side of the variac to calculate actual wattage.
EDIT: If you measure wattage from the primary side of the transformer you'll be measuring the transformers ineffiency also ,given of as heat to surrounding air.
if a 5 amp variac when set at 100volts was heating my cartridges up to 200watts then for a 2amp variac I would need to set the output to at least double or 200volts to achive the same results.
if a 5 amp variac when set at 100volts was heating my cartridges up to 200watts then for a (2.5 amp) (corrected) variac I would need to set the output to at least double or 200volts to achive the same results.
If so it sounds like I made a poor investment...
Yes your on the right track, kinda
but you have fixed resistance (ohms)
if you double the volts you can half the current (amps) for the same wattage(ohms will change)
If you half the volts you double the current(amps) for the same wattage.(ohms will change)
BUT the Ohms will need to be different, You have fixed ohms(resistance)
Since your ohms is fixed(on secondary side),your only variables are 0 to 140 volts or 0 to 2.4 amps.
Electricity is dangerous. More so than filling a second stage of a cascade while it's running, or using propane as a sheilding gas.
There really isn't an elegant way to say this - in terms of safety you clearly lack the most basic electrical knowledge to undertake this type of electrical construction project.
If you wire your variac for line output @120Vout you get the 2.4A - max constant current allowable in the winding at rated voltage.
If you wire in overvoltage configuration @140V you get 2A. - more voltage at the expensive of current (minor transformer action)
Also note that the spec sheet says 350-1200 cycles per second.
There really isn't an elegant way to say this - in terms of safety you clearly lack the most basic electrical knowledge to undertake this type of electrical construction project.
Come on man of course I lack basic understanding of electrical calculations and of course its dangerous but its my risk and one i have taken before successfully. My question has nothing to do with wiring a variac been there done that with my W5M my question was in wether downgrading to a W2 was going to leave me underpowered and the answer is yes...
In parting thanks again Walt for the assist its much appreciated and SexyMF I hope you know im not angry for you ragging on my lack of electrical prowess?
SexyMF good catch on the freq, I just looked @ the chart....... didn't read even read the first paragraph. 350 to 1200 cycles(hertz) not even designed for standard current. As everyone knows standard in USA is 60 hertz & 50 hertz for Europe.
Forums are not for getting personal. I read and reply to them knowing that they are public. Electroincs and electrical is my profession. So that is my input to the forums. Most people are worried about venting gas. I'm more concerned about electrical wiring.
After all, you can create and play with whatever electrical gadgets you like. As long as you don't sell them. The only ramifications are insurance and personal safety.
As for the frequency. You can run it on a lower frequency but I suspect the efficiency will plummet because you are way out of spec.
Linear Mode
