Transformer Current Loss With Little Voltage Loss

[bhsrnd]

Is it ever possible that amperage levels provided by the utility could sag without sagging the voltage to below nominal levels (i.e.- 480v)? If so, would this be transformer related?

 

[charlie b]

I don't follow. If the utility amps "sag," that is get lower, that will increase (not decrease) the voltage at every point along the line. What are you trying to ask?

 

[steve066]

If I understand the question right, the answer is basically no. Ohms law must hold at any point in the system. Say your load is a 480 ohm resistor. At 480V, it normally draws 1 Amp. If the utility can only supply 1/2 amp (say, because it is overloaded) then the voltage across the load will have to drop to 240V. There is no way the current can be anything other than 1 amp if the voltage is 480V and the load is 1 ohm.

Motor loads and capacitive loads and nonlinear sources and loads make the issue a little more complicated. And if we consider standing waves, then the voltage and current can be different at different points along a transmission line. But I think it would be a very rare case if you measured normal voltage but the utility couldn't provide the current draw.

Edit: I am also assuming you are measuring the voltage with the load connected. If you measure the voltage without the load connected, the answer would be a definate yes.
Steve

 

[bhsrnd]

Steve, you answered my question. What you said was my assumption but I wanted someone more knowledgable to verify it for me. Thanks!