[RE-wrenches] Inverter for fire protection pump

Sat Aug 28 08:44:20 PDT 2010

Wrenches,

This group's experience, collective wisdom, and willingness to share 
practical knowledge and interesting ideas are how I envision higher 
education in the future. Thank you all for your helpful information. I'll 
report back what the customer decides to do.

Joel Davidson

----- Original Message ----- 
From: "Darryl Thayer" <daryl_solar at yahoo.com>
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Sent: Saturday, August 28, 2010 8:24 AM
Subject: Re: [RE-wrenches] Inverter for fire protection pump

Sorry this could be more helpful if I had a better memory, I don't mean to 
ramble, but some wrenches may find value.

I am working on a standalone system now and I am in testing.  Normally I use 
OUtback, (and I am very happy)  and this time I decided to use Magnum 4024 
AE.  The job has both a large motor and is AC coupled to DGI inverter.  The 
large motor draws over 120 amp (120 volt) surge when connected to a grid 
source.  I have started this motor in test repeatedly My Greenlee amp clamp 
says it is surging at 90 amps! The VOM says the min voltage is 97 volts. 
This is on ONE 4024 AE,  Magnum is getting close to release of the paralled 
version The test battery set is Trojan T105 single string, and the surge DC 
measured by Ideal DC clamp on is 280 amps.  Voltage and minimum battery 
voltage is 21 volts Ideal VOM.  I would think that the parrellel version 
could handle your motor.

Old system
I did a fire pump install in a large residence, I think back in 2004?  the 
specs were similar except the starting surge was higher and the running was 
almost the same (maximum of 20 amps and less depending upon flow).  I used 
an Odd number of OUtback inverters (5) but not all were to this task.  First 
the starting surge measured by my greenlee clamp-on amp meter was higher on 
the grid than it is on the inverters.  I did a lot of field tests, however I 
do not know where I put the data.  I noticed that if I had fully charged 
batteries the starting was 100% reliable but on batteries at near 50% SoC 
the system started to fault on "low AC" during start-up The batteries were 
L-16 Surrette 48 volt string. If the system was started every five minutes 
it would fault, but if a longer waiting period  I remember during the course 
of the job I started the pump over 100 times in test mode with out a 
failure.  (this system gets annual tests and no problems so far)

Pumps:  We found that the pump current draw depended upon the flow rate we 
allowed..  If we had one head open, the current draw was less than all heads 
open.  The maximum curent draw was at some flow rate in the middle flow 
range! The starting surge was independent of whether the valve was open or 
closed.  If it would be possible to use a SQflex this would be a good 
choise.  Finally this system is grid tied and has a relay to Outback if the 
Grid should fail and it has a generator inlet box if a generator is avaiable 
to take the load.

--- On Fri, 8/27/10, Joel Davidson <joel.davidson at sbcglobal.net> wrote:

> From: Joel Davidson <joel.davidson at sbcglobal.net>
> Subject: Re: [RE-wrenches] Inverter for fire protection pump
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Friday, August 27, 2010, 9:50 PM
> Hi Ray,
>
> Thank you for your input. The pump is part of a fire
> protection system that sucks water out of the swimming pool
> and pumps it to roof sprinklers with fire retardant added to
> the water. I'll forward your email to my colleague who has
> the details.
>
> Best regards,
> Joel Davidson
>
> ----- Original Message ----- From: "R Ray Walters" <ray at solarray.com>
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Sent: Friday, August 27, 2010 7:23 PM
> Subject: Re: [RE-wrenches] Inverter for fire protection
> pump
>
>
> > Forgot to mention the usual info: look at the pump to
> see if a smaller or no surge Grundfos SQE might be able to
> handle the flow rate and pressure needed.
> > Pumps are cheap, when you're considering multiple
> inverters......
> > Given what you mentioned (110 amp surge at 240 vac), I
> don't think even a quad stack of Outbacks could do it. (
> please ignore my earlier post)
> > A quad stack could run that, just not start it.
> Franklin makes a soft start controller, that might work with
> that pump. What is the Horse power rating?
> >
> > R. Walters
> > ray at solarray.com
> > Solar Engineer
> >
> >
> >
> >
> > On Aug 27, 2010, at 3:52 PM, R Ray Walters wrote:
> >
> >> Little beyond a pair of Outbacks, possibly a
> pair of Magnasine inverters, or a quad stack of Outbacks.
> >>
> >> R. Walters
> >> ray at solarray.com
> >> Solar Engineer
> >>
> >>
> >>
> >>
> >> On Aug 26, 2010, at 2:41 PM, Joel Davidson wrote:
> >>
> >>> Wrenches,
> >>> Our customer has a fire protection pumping
> system that operates at 240VAC and 22 amps with a 110 amps
> starting surge. The pump will only be used for up to 4 hours
> in an emergency (but hopefully never). The customer wants an
> inverter and battery (no generator or PV) in case grid power
> is destroyed by fire. What inverter(s) do you recommend?
> Thank you very much for sharing your off-grid knowledge.
> >>> Joel Davidson
> >>>
> >>>
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