Kevin.M
New User
- Location
- Sacramento CA
I am looking to power a 100HP 480/3p motor for irrigation and looking to power it with solar. I have come up with 100KWAC can someone help confirm
480V 3P 100 HP motor, How much solar would I need
- Thread starter Kevin.M
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- Status
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Will this be an off-grid location? If so, do you want to run the motor reliably through low sun, partial clouds, etc? And how do you intend to start the motor?
If this is a grid tied project and you are just trying to offset the average power consumption of the motor it is an easier design project and a lot cheaper.
How many hours per day will the motor have to run? At full speed?
What is your latitude and will you need to produce full motor consumption during the winter months too?
If this is a grid tied project and you are just trying to offset the average power consumption of the motor it is an easier design project and a lot cheaper.
How many hours per day will the motor have to run? At full speed?
What is your latitude and will you need to produce full motor consumption during the winter months too?
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Are you looking to offset an electric bill or power it off grid? For off grid it gets a lot more complicated; you cannot just put up modules and an inverter.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Everything GD said, plus this;
The 100kW is just a gross guesstimation tool for trying to figure out how much diesel generator capacity you need for running loads. Unfortunately is has no bearing on what it might take to START that load, and even though a rotating generator can provide you with a LITTLE bit of fudge factor there, you still need a lot of reserve capacity if it's only one motor. the 1kW/HP rule is for when you have a bunch of smaller motors and you want to size the generator for them all, assuming you start them one at a time. On a solar power system, you don't even have that little fudge factor... That motor, if started Across-the-Line, will want to see 600% of it's FLA for a few seconds. So converted to kw, you are looking at a 450kW minimum solar system. You could cut that down by using something like a VFD to control the starting power requirements, hence the questions as to how you plan on starting it. A Soft Starter would be the least you should do, but I'm not sure many soft starters will like running off of a solar inverter. If it were me, I would use a VFD and feed the solar DC directly into the bus of the drive, bypass the AC inverter; it's redundant. But now you need to factor in the motor voltage and thereby the VFD voltage because that affects your solar panel configuration. For a solar panel system, 100HP at 240V is a lot of current, 100HP at 480V is a lot of voltage. There is no free lunch...
Bottom line, 100HP is a lot of solar power. Grossly inaccurate guestimation is you are probably going to need around .11 acres of solar panels to run that motor.
junkhound
Senior Member
- Location
- Renton, WA
- Occupation
- EE, power electronics specialty
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
Sorry; I am not following you. Are you talking about off grid or grid tied solar? It appears you are talking about off grid solar but you seem to be talking only about inverter power. That is an apples to oranges comparison; you cannot power an off grid AC motor by simply throwing out a bunch of modules and connecting them to an inverter. There are no solar inverters that can supply more than a couple thousand Watts of AC power without either a battery bank or a grid connection.
If you have a battery bank, that's where your motor starting current comes from, not the solar; in fact, with an off grid PV system you are always running off the batteries. The only purpose of the PV is to keep the batteries charged up. The bottom line isn't so much the number of solar modules you would have to have to supply the average load, it's the ampere-hours and discharge rate of battery capacity you'd have to have to start and run the motor.
The way you must design an off grid system is this: you start with the load requirements, both peak demand and average daily usage, plus the days of autonomy (days without much sunshine) that you want to be able to tolerate without losing power. Critical to that analysis is how many hours a day you need to run the motor, how much current it draws on startup, and how many times a day it starts. Using those numbers you calculate the battery capacity that you will need. Then and only then can you calculate the size solar array you will need at your particular location to keep the batteries charged up.
There is no simple straightforward answer to the OP's question.
kwired
Electron manager
- Location
- NE Nebraska
If it were cost effective enough I would think we would see some of those around here, I have never seen such a system.
Only solar well I am aware of is one guy that has one for a small pasture pump to pump water for cows in that pasture in remote location - probably only a 1/2 Hp well or maybe even less then that and only needs to pump a few hundred gallons of water but has all day to do it for the most part.
Only solar well I am aware of is one guy that has one for a small pasture pump to pump water for cows in that pasture in remote location - probably only a 1/2 Hp well or maybe even less then that and only needs to pump a few hundred gallons of water but has all day to do it for the most part.
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