MiguelM
Member
- Location
- Angel Fire, NM
My father-in-law has a PV power back-up system installed. The voltage supplied by each inverter is rated for 105V (it is a stacked system) but metered, shows 99-101V. He wants to use it to run his well pump. My concern is that the if the well pump motor is not supplied with 120-110V, it may overheat and "burn up". I don't have the specs on the well pump.
Here's where my limited knowledge derails me:
My theory in electrical tells me that when the voltage is lower, the current being pulled to supply the power required by the motor should increase. However,I ran the well pump on the inverters and checked the voltage at the ac supply to the pump. The meter read 99 volts on each leg or 199 across both. I then metered the current through each leg with a loop meter and read 5.24A.
I did the same, this time with the supply to the pump coming from the residential supply. Each leg read 124V or 250V across both legs. The current read at 5.9A through each leg.
In other words, the current being pulled by the motor was higher with a lower voltage-opposite of what I expected.
I did the same experimenet with a halogen light and again with a shop vac. The same result. The a/c current drawn by each of these items was higher when the voltage supplied was lower.
Please explain this before I have to pull out my electrical theory books from the attic.
Thanks.
Miguel M.
Here's where my limited knowledge derails me:
My theory in electrical tells me that when the voltage is lower, the current being pulled to supply the power required by the motor should increase. However,I ran the well pump on the inverters and checked the voltage at the ac supply to the pump. The meter read 99 volts on each leg or 199 across both. I then metered the current through each leg with a loop meter and read 5.24A.
I did the same, this time with the supply to the pump coming from the residential supply. Each leg read 124V or 250V across both legs. The current read at 5.9A through each leg.
In other words, the current being pulled by the motor was higher with a lower voltage-opposite of what I expected.
I did the same experimenet with a halogen light and again with a shop vac. The same result. The a/c current drawn by each of these items was higher when the voltage supplied was lower.
Please explain this before I have to pull out my electrical theory books from the attic.
Thanks.
Miguel M.