We have been pumping well water into a 1000 gallon sand filter and then from the sand filter to a pressure tank for many years. Since the sand filter has been in the mix, there is no need for high flow pumps, so we have replaced pumps with 1/2 hp 2 wire pumps over the past few years (more than one well). I am assuming these two wire pumps are either shaded pole or might be permanent split capacitor type with the capacitor hidden somewhere inside the pump unit. We still have a 3 wire with a starter box in one well.
I have a split phase sub-panel box with a transfer switch for emergency power and would really like to be able to run a well pump from an inverter without spending a lot for something that might never see use. Recently I purchased a PowerJack 6000W (24v input) for less than $200 on Ebay. Most of the Ebay listings show "Continuous rating" that is 50% of the number on the inverter's label, so I assume the 6000W is a product name, not specifically meant to be 6000 watt rated. The unit is however rated to carry a surge of 9000W. So just call it a 3000 watt unit. I am not sure what the starting current is on the 2 wire well pump but it is less than a normal capacitor start motor, so I had hopes it would work. I tested it on 2 of 3 of my 2 wire pumps and it worked just fine. The three wire pump it would not start. I think the starter box as a current relay, meaning the coil is pulled in by a specific current load and not by a voltage on the coil. You can spot those type relays by the size wire on the coil. Big fat wire = current sensitive. That 3 wire pump, it didn't start and the inverter didn't really complain either. My wife was monitoring the inverter input amps, showing 170 amps. I was not able to monitor the line voltage to the pump at the time but I expect it was low enough that the current was too low for the current relay to engage the start winding. Note, I have two BYD used batteries connected to the inverter.
I plan to be able to capture some starting current data with some additional tests, when I have time. But I am very happy to know we can pump into the filter and into the pressure tank with the existing setup. I wanted to share this success because I was not sure if it would start the pump or not.
I have a split phase sub-panel box with a transfer switch for emergency power and would really like to be able to run a well pump from an inverter without spending a lot for something that might never see use. Recently I purchased a PowerJack 6000W (24v input) for less than $200 on Ebay. Most of the Ebay listings show "Continuous rating" that is 50% of the number on the inverter's label, so I assume the 6000W is a product name, not specifically meant to be 6000 watt rated. The unit is however rated to carry a surge of 9000W. So just call it a 3000 watt unit. I am not sure what the starting current is on the 2 wire well pump but it is less than a normal capacitor start motor, so I had hopes it would work. I tested it on 2 of 3 of my 2 wire pumps and it worked just fine. The three wire pump it would not start. I think the starter box as a current relay, meaning the coil is pulled in by a specific current load and not by a voltage on the coil. You can spot those type relays by the size wire on the coil. Big fat wire = current sensitive. That 3 wire pump, it didn't start and the inverter didn't really complain either. My wife was monitoring the inverter input amps, showing 170 amps. I was not able to monitor the line voltage to the pump at the time but I expect it was low enough that the current was too low for the current relay to engage the start winding. Note, I have two BYD used batteries connected to the inverter.
I plan to be able to capture some starting current data with some additional tests, when I have time. But I am very happy to know we can pump into the filter and into the pressure tank with the existing setup. I wanted to share this success because I was not sure if it would start the pump or not.