[RE-wrenches] Magnum and Pumps

[Jason Szumlanski]

To further qualify my statements, the inverter will start the pump without
issue, but I should echo the warnings by others that if there are other
loads present, especially other motor loads that could start ​concurrently,
you may experience issues. As long as your customer understands the
limitations and possibilities, you may be just fine.


Jason Szumlanski

​Fafco Solar​



On Wed, Jul 2, 2014 at 11:00 AM, Jason Szumlanski <jason at fafcosolar.com>
wrote:

> 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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