Basic electrical lesson

[k0ua]

Imagine my surprise when I first heard a boiler rated in hp. I know it's the type of measurement, but it seemed strange. Hmm... makes me wonder how my tractor's 38 hp converts to btus/hr.

Not quite electrical I know, but I thought it was relevant nonetheless.

95365.81684 btu/hr.

 

[RobertBrown]

has anyone else ever tested a 9 vdc battery with your tongue......:anyone:
or am I the only one. :number1:




Ever get a fresh one and see who could hold on the tip of their tongue the longest?

 

[k0ua]

has anyone else ever tested a 9 vdc battery with your tongue......:anyone:
or am I the only one. :number1:




Ever get a fresh one and see who could hold on the tip of their tongue the longest?

I have done that thousands of times. 9V is about all you want though:shocked: If you can hold it on for a while it is not very good, or you are one heck of a man!

 

[Sparks45]

Have you ever noticed that the largest single digit is always one unit smaller than the base? Like, binary (base 2) is 1, decimal (base 10) is 9, hexadecimal (base 16) is F (arabic numerals 1 thru 9 then A thru F). To express the base number (in each base) it's 10, you just have to annotate the base in subscript. And 0 (zero) is just a placeholder. I found this the easiest way to explain things to young sailors who asked too many questions :confused2:
Charlie

 

[mikehaugen]

So here is something I've always wondered about... why are some things like smaller generators and power supplies rated in watts or kw, but other things like large generators and transformers rated in kva? Aren't they essentially the same units?

 

[k0ua]

So here is something I've always wondered about... why are some things like smaller generators and power supplies rated in watts or kw, but other things like large generators and transformers rated in kva? Aren't they essentially the same units?

Mike they are not exactly the same thing. In AC systems you have to take into account reactive loade. For instance on a motor the load is inductive and current lags voltage and some power flows back into the circuit on part of the cycle. KW refers to the power consumed in actual doing actual work, but KVA is potential power, but depending on if the power factor is 1 (non reactive) then they would be the same. I may not have explained this very well...I am not an electrical engineer, but I did play one on TV once.

James K0UA

 

[CobyRupert]

Mike they are not exactly the same thing. In AC systems you have to take into account reactive loade. For instance on a motor the load is inductive and current lags voltage and some power flows back into the circuit on part of the cycle. KW refers to the power consumed in actual doing actual work, but KVA is potential power, but depending on if the power factor is 1 (non reactive) then they would be the same. I may not have explained this very well...I am not an electrical engineer, but I did play one on TV once.
James K0UA

I once had Watts (real power) vs VA (Volt-Amps, or Volts x Amps) vs reactive power (VARS) explained to me by an electrical engineering professor like this (hold on it's very technical):
Volt-Amps is like the capacity of a mug of beer, lets say it holds a 1.5 pints; whereas Watts is the actual drinkable beer (minus the foam), lets say this is a pint. The reactive power (VARS) is the "useless" foam that requires mug capacity. In this case our beer power factor (do not confuse this with beer muscles) is 1 pint beer/1.5 capacity used or 66%.

Yep I learned a lot in college. Mostly about beer.

 

[mikehaugen]

Mike they are not exactly the same thing. In AC systems you have to take into account reactive loade. For instance on a motor the load is inductive and current lags voltage and some power flows back into the circuit on part of the cycle. KW refers to the power consumed in actual doing actual work, but KVA is potential power, but depending on if the power factor is 1 (non reactive) then they would be the same. I may not have explained this very well...I am not an electrical engineer, but I did play one on TV once.

James K0UA

I once had Watts (real power) vs VA (Volt-Amps, or Volts x Amps) vs reactive power (VARS) explained to me by an electrical engineering professor like this (hold on it's very technical):
Volt-Amps is like the capacity of a mug of beer, lets say it holds a 1.5 pints; whereas Watts is the actual drinkable beer (minus the foam), lets say this is a pint. The reactive power (VARS) is the "useless" foam that requires mug capacity. In this case our beer power factor (do not confuse this with beer muscles) is 1 pint beer/1.5 capacity used or 66%.

Yep I learned a lot in college. Mostly about beer.

Thanks guys... still not real clear, but I at least can recognize that there is a difference. :laughing:

 

[k0ua]

I once had Watts (real power) vs VA (Volt-Amps, or Volts x Amps) vs reactive power (VARS) explained to me by an electrical engineering professor like this (hold on it's very technical):
Volt-Amps is like the capacity of a mug of beer, lets say it holds a 1.5 pints; whereas Watts is the actual drinkable beer (minus the foam), lets say this is a pint. The reactive power (VARS) is the "useless" foam that requires mug capacity. In this case our beer power factor (do not confuse this with beer muscles) is 1 pint beer/1.5 capacity used or 66%.

Yep I learned a lot in college. Mostly about beer.

Wow. 66% PF would be a highly reactive beer mug! You better throw in some compensation pretty quick!.. maybe a shot of Whiskey?