[RE-wrenches] 10 HP mtr

[Darryl Thayer]

I agree, but if the motor is running up to overload it may use more than the 10 HP by 1.15  any energy will be subtracted from the bill, if you have net metering, let us know some of the other particulars.

darryl

- On Fri, 11/6/09, Mick Abraham <mick at abrahamsolar.com> wrote:

> From: Mick Abraham <mick at abrahamsolar.com>
> Subject: Re: [RE-wrenches] 10 HP mtr
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Friday, November 6, 2009, 6:00 PM
> Motor math can be fun!
> 
> If the motor is 50% efficient, begin with 1 horsepower =
> 746 watts, so 10 horsepower = 7,460 watts but that would be
> at (the impossible) 100% efficiency.
> 
> Now apply the efficiency factor: 7,460 watts/.5 efficiency
> assumption = 14,920 watts (simplified down now to 14.9
> kilowatts)
> 
> 
> 
> 14.9 kW x 24 hours = 358 kilowatt-hours that must be offset
> per day. Multiply by 30 to get 10,740 kilowatt-hours that
> must be offset per month. 
> 
> If the motor efficiency is different than 50%, start over
> but follow the same mathematical pattern. 
> 
> 
> 
> Note: a motor that is rated for 10 horsepower may or may
> not actually be delivering 10 horsepower at the shaft. If
> the torque/RPM requirement for the pump is less than 10hp
> the motor will follow the load and the motor's power
> requirement will be lower.
> 
> 
> 
> Best idea: wait until the pumping system is installed and
> running, then measure the amperage and do math from there.
> OR: try to get a kilowatt-hour meter installed ahead of the
> pump motor and just read the kWh after one day, seven days,
> or a month.
> 
> 
> 
> Jolliness,
> 
> Mick Abraham, Proprietor
> www.abrahamsolar.com
> 
> Voice: 970-731-4675
> 
> 
> 
> On Fri, Nov 6, 2009 at 4:05 PM,
> Max Balchowsky <max at seesolar.com>
> wrote:
> 
> 
> I have a request to install an array to offset the usage
> for a 10 HP irrigation pump that I'm told is going to
> run 24/7 in PG&E territory,
> 
> what do you motor guys know about the usage I should
>  expect..........
> 
> 
> 
> Max Balchowsky
> 
> SEE Systems
> 
> 
> 
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