[RE-wrenches] Starting 3/4 Sub Pump (was Power Factor)

Allan Sindelar allan at positiveenergysolar.com
Thu Jul 30 17:16:59 PDT 2009


Matt and boB,
This is only somewhat relevant, but may help:
A few days ago, on initial bootup of a new system with a Magnum MS4024AE, we
easily ran a 1HP submersible at nearly 500' head plus pressurizing (single
pump system). However, this was a Grundfos SQ, so the soft-start made it
much easier. Steady draw was about 88ADC at 25 VDC, or around 2200 watts. I
had cautioned the client that this combination wasn't certain to work,
although I expected that it would. 

Allan Sindelar
Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of boB Gudgel
Sent: Thursday, July 30, 2009 4:45 PM
To: Matt
Cc: RE-wrenches
Subject: Re: [RE-wrenches] Power Factor

Matt wrote:
> Possibly a PF question, or maybe one for Magnum - boB,
>
> One of the guys at work is (almost) running a 3/4 hp sub pump with a Magna
AE 48. Or rather, he isn't. According to him when he first fired it up, it
operated the pump just fine. The next time he tried, though. he couldn't
even get a buzz out of the starter. No workee.
>   
Sounds kind of like a "pump is broken or worn out" problem, doesn't it ?

If there is enough ac voltage applied to the pump, the it should do 
~something~, or lights should dim or some
kind of sign should show itself, wouldn't you think ?   Otherwise, I 
would suspect it might be a surge problem.

Is there a pilot light or something ?   Maybe a fuse blew or breaker 
tripped somewhere ?   (when the pump went off?)

Doesn't sound like a PF problem though... However,  since you mention 
it, with loads that are not a 1.0 power factor,
at least for displacement power factor, when reactive phase shift is 
involved, the inverter must be able to "sink" current
from the stored reactive energy as well as be a source to the motor.   
The Magnum does that just fine, as does any other
decent inverter.

Maybe Tony, Eldon or Gary at Magnum has seen this before ?    425-353-8833

boB





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