<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">If you have a clamp on meter that can capture inrush current (I use a Fluke 337 for this) you can get a good idea of the starting current needed.<div><br></div><div>One problem is that while backing up the house, you will likely have other loads operating when the pump starts which will decrease the available surge current. I would recommend using a stacked pair of 4448’s as a minimum if you have other house loads. <div><div apple-content-edited="true"><br>Larry Crutcher<br>Starlight Solar Power Systems<br><br><br><br>
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<br><div><div>On Jul 2, 2014, at 8:17 AM, Drake <<a href="mailto:drake.chamberlin@redwoodalliance.org">drake.chamberlin@redwoodalliance.org</a>> wrote:</div><br class="Apple-interchange-newline"><div>
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Hello Wrenches,<br><br>
We are hoping to use a Magnum PAE 4448 to back up a household that
includes a 3/4 HP deep well pump. There is about 120 feet of vertical
rise and about 1000 feet of horizontal distance. <br><br>
I have been told that there is a correlation between the locked rotor
current of a pump and the predictable ability of a specified inverter to
power that pump. <br><br>
The plumber who installed the pump left no paperwork and retained no
records of what pump he put in the hole last year. He could only say it
was a 3/4 HP pump. We are therefore unable to obtain the manufacturer's
nameplate specifications.<br><br>
The Magnum PAE 4448 has a 1 mS surge of 70 A (at 240 V) and a 100 MS
surge of 40 A. According to the NEC Table 430.251(A), a 3/4 HP motor has
a locked rotor current of 41.4 amps at 230 V. <br><br>
This inverter can surge at 35.4 A for 5 seconds. The specified battery
bank will be 8 Full River L-16 AGMs. Can anyone say if:
<ul>
<li>Is there enough information to know if this setup will handle the
pump, and if so, will it?
</li><li>How can an inverter's ability to power a motor or pump be calculated
by knowing its locked rotor current? Which surge periods should be
compared to the locked rotor current?
</li><li>Does the surge current need to equal locked rotor. How long must the
inverter meet its required maximum surge?
</li><li>From experience with Magnums and pumps, does this seem like a good
combination?
</li></ul><br>
Thank you,<br><br>
Drake <br><br>
Drake Chamberlin<br>
<i>Athens Electric LLC<br>
OH License 44810<br>
CO License 3773<br>
NABCEP Certified Solar PV <br>
740-448-7328<br>
</i><a href="http://athens-electric.com/">http://athens-electric.com/</a>
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