[RE-wrenches] 100ms for Locked Rotor Amps?

[Jeff Clearwater]

Thanks Ray and Jerry,

Great to hear from you both with your years of combined experience :)

So yes looking at the 5 sec has me switching back to a trusty Radian - 
even then from what you are saying it may not work.

And you are right Ray -  Outback is careful to rate the "overload 
capability" in KVA rather than KW due most likely to voltage sag of course.

So this 53 LRA 2 HP motor - if I can only trust the 5 second (50 A) 
might not start - especially with other loads on the system?

RADIAN SURGE RATINGS:

Maximum Output Current
1 ms peak 100 Amps AC at 240 VAC, 200 Amps AC at 120 VAC
100 ms RMS 70.7 Amps AC at 240 VAC

Overload Capability
100 ms surge 16.97 kVa
5 seconds 12 kVa
30 minute 9 kVa

Other's experience with 2 HP sewage pump or well pump motors on a Radian?

Thanks!

Jeff


Ray wrote on 7/25/19 5:48 PM:

> I only look at the 5 sec and 30 sec surge ratings to get an idea what 
> an inverter can really do in the real world.  All those millisecond 
> ratings/ in rush current specs won't get a pump or motor started, and 
> will basically just get you into trouble.  The reason they have those 
> ratings in amps and not watts, is that the voltage craters during that 
> 100mS surge.
>
> I can't tell you how many times we tried to start a pump, compressor, 
> or large table saw, and the inverter just shut off, even though the 
> "in rush current" was within the theoretical inverter capacity.  
> Actual Wrench list testimonials are much more valuable than those 
> arcane specs.
>
> Ray Walters
> Remote Solar
> 303 505-8760
> On 7/25/19 5:15 PM, Jeff Clearwater wrote:
>> Hey There Wrenches,
>>
>> So be advised that after a little research the SW dual stack will NOT 
>> double the surge ratings of a single SW.
>>
>> But that brings me to my second question:
>>
>> What inverter surge rating should one refer to when looking at 
>> maximum Inrush or LRA - 1ms?  100ms?  1 sec?
>>
>> Yourengineering wisdom welcomed!
>>
>> Thanks,
>>
>> Jeff
>>
>>
>>
>> Jeff Clearwater wrote on 7/23/19 8:27 PM:
>>
>>> Thanks for the tip!  I'll check the firmware.
>>>
>>> Dave Angelini Offgrid Solar wrote on 7/22/19 9:11 AM:
>>>
>>>> Hi Jeff,
>>>>
>>>> I am not going to guess if this will work, it should.  I use XW's 
>>>> because they start anything I have come across.
>>>>
>>>> If you do this, make sure but SW's have the latest and same 
>>>> firmware. There were problems with stacked SW's early on in their 
>>>> development.
>>>>
>>>> *Dave Angelini Offgrid Solar "we go where powerlines don't" 
>>>> http://members.sti.net/offgridsolar/ e-mail offgridsolar at sti.net 
>>>> <mailto:offgridsolar at sti.net> text 209 813 0060*
>>>>
>>>> On Mon, 22 Jul 2019 07:26:07 -0700, Jeff Clearwater 
>>>> <jeffc at villagepowerdesign.com> wrote:
>>>>
>>>>> Hey Esteemed Wrenches,
>>>>>
>>>>> So I recently built a power trailer with a single 4 KW (4048) 
>>>>> Schneider SW for a client with a moderate cabin lifestyle.
>>>>>
>>>>> But he lives on a high hill and even though his 2 HP Macerator is 
>>>>> only rated at 15 amps continuous that baby starts up with a 
>>>>> whopping kick - probably close to or at it's 53 Amps Locked Rotor 
>>>>> rating.
>>>>>
>>>>> The SW has the following surge capability:
>>>>>
>>>>> SW 4048 Rated@ 240 Volts:
>>>>> Continuous - 15.2 Amps 3700 Watts
>>>>> 30 Minutes - 18.3 Amps 4400 Watts
>>>>> 5 Secs - 29.2 Amps 7000 Watts
>>>>> Max (100ms?) - 41 Amps - 9840 Watts
>>>>>
>>>>> Can I be confidant that 2 stacked SWs will start this baby?
>>>>>
>>>>> Any experience with similar macerators - or simply educated guesses?
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Jeff
>>>>>
>>>> -- 
>>>>   
>>>> *Dave Angelini Offgrid Solar "we go where powerlines don't" 
>>>> http://members.sti.net/offgridsolar/ e-mail offgridsolar at sti.net 
>>>> <mailto:offgridsolar at sti.net> text 209 813 0060*
>>>
>>>
>>>
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