effects of / protection from undervoltage
In the 'do I really need a surge protector for a basic trailer' thread, saw a lot about 'undervoltage'...many responses that 'undervoltage is more common that a surge, and causes as much or more damag...
Forum Discussion
wa8yxm wrote:valhalla360 wrote:
A key formula to remember Watts = Volts * Amps. Electric motors generally pull the same wattage, so if the volts go down, the amps must go up to compensate. Items like a toaster draw a steady amperage, so if the voltage goes down, they just don't get as hot.
That formula is actually not complete. and before you think I'm critical of you. I am college trained and it took me 40 years to figure it out :)
One of the interesting things about teh Kill-A-Watt meter is the folks who designed it.. Figured it out
For things like a space heater.. Or an electric Skillet.. YES Volts*Amps=Watts
For motors not so easy as there is one more variable (Power factor) the Kill-a-watt computes both Volt-Amps (Volts*amps) Watts (Almost always less) and power factor (The relationship between the voltage and current sine waves)
I've heard of one case where the power factor was near zero and the motor would not run.... I know the "Engineer" who fixed it (ok so he does not even have a high school diploma but he's very well self taught)
Yes, I over simplified but figured the OP wasn't interested in the intricacies but the general idea.
