[RE-wrenches] Magnum and Pumps

Jason Szumlanski jason at fafcosolar.com
Wed Jul 2 08:00:37 PDT 2014


For what it's worth, I've run a single speed 1.5HP pool pump with a
MS4448PAE in a mobile application on a 38.4kWh battery bank (sixteen Rolls
S-530's). I have also run a 2.5HP Hayward EcoStar Variable Speed pool pump
at full RPM, but that startup current is likely less than you well pump.

I'm going to guess your 3/4HP well pump will be a breeze to start with this
inverter.


Jason Szumlanski

​Fafco Solar​



On Wed, Jul 2, 2014 at 10:47 AM, Allan Sindelar <allan at sindelarsolar.com>
wrote:

>  Drake,
> As a normal CYA, I'll always gently let a customer know that this (or any)
> particular combination of inverter and load sometimes proves incompatible,
> just in case the unexpected happens. (We once had a MS4448 that would not
> reliably start and run a condensing boiler; a switch to a different boiler
> resolved the issue.)
>
> Having said that note of caution, I wouldn't give it any concern. 3/4 HP
> and 1 HP well pumps have never been an issue; I would expect 1.5 HP to be
> easy to run. At 2 HP I'd be asking these questions here.
>
> You might check that it's a 3-wire, capacitor-start motor, but nowadays
> nearly all are. Two-wire pumps (with no control box) can add 50% to the
> surge.
>
> The Magnum has a fairly poor voltage regulation response. Sometimes the AC
> voltage can drop to ~80 VAC momentarily. So you might also caution your
> customer that the lights may flicker when the pump starts. In our home we
> know whenever our Kenmore fridge turns on.
>
> Allan
>
>  *Allan Sindelar*
> allan at sindelarsolar.com
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder (Retired), Positive Energy, Inc.
> *505 780-2738 <505%20780-2738> cell*
>
>
>  On 7/2/2014 8:17 AM, Drake wrote:
>
> Hello Wrenches,
>
> 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.
>
> 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.
>
> 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.
>
> 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.
>
> 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:
>
>    - Is there enough information to know if this setup will handle the
>    pump, and if so, will it?
>    - 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?
>    - Does the surge current need to equal locked rotor. How long must the
>    inverter meet its required maximum surge?
>    - From experience with Magnums and pumps, does this seem like a good
>    combination?
>
>
> Thank you,
>
> Drake
>
> Drake Chamberlin
>
>
>
>
>
> *Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified
> Solar PV 740-448-7328 <740-448-7328> *http://athens-electric.com/
>
>
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