[RE-wrenches] Magnum and Pumps

Jason Szumlanski jason at fafcosolar.com
Wed Jul 2 12:17:12 PDT 2014


Sorry, typo - that's a 48V string (one string of 8 batteries).

Jason Szumlansk​i

Fafco Solar



On Wed, Jul 2, 2014 at 3:15 PM, Jason Szumlanski <jason at fafcosolar.com>
wrote:

> ​Even at 9600W, which is above the 5 second surge rating of the inverter,​
> we're looking at about 200A on the DC side, which would be a 1-hr rate on
> an L-16 string. While that is high, it should not be an issue. Even at the
> 1ms surge of 16,800W, a 48 string of L16's should be able to handle that.
>
> Jason Szumlanski
>
> ​Fafco Solar​
>
>
>
>
>
> On Wed, Jul 2, 2014 at 2:35 PM, Roy Butler <roy at four-winds-energy.com>
> wrote:
>
>>  I haven't seen anyone mention the battery bank. If I understand
>> correctly, there's a single string of sealed
>> L16 batteries on this inverter. I have my doubts as to whether or not
>> that bank can provide the high current
>> the inverter needs to start this load.
>>
>> Roy Butler
>> NABCEP Certified Solar PV Installer®
>> NYSERDA eligible PV & wind installer
>> IREC Certified Master Trainer™ for Small Wind Installer
>> Four Winds Renewable Energy, LLC
>> 8902 Route 46, Arkport, NY 14807607-324-9747  www.four-winds-energy.com
>>
>> Join us at the 10th Annual Small Wind Conference
>> A Gathering of Installers, Manufacturers, Dealers, & Distributors
>> June 17 and 18, 2014 in Stevens Point, Wisconsinwww.smallwindconference.com
>>
>> Although no trees were killed in the sending of this message,
>> a large number of electrons were terribly inconvenienced.
>>
>>
>>
>> On 7/2/2014 2:10 PM, Jason Szumlanski wrote:
>>
>>  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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