Sizing Generator- Florida Nursery

[theplantman]

We have recently installed a new 20hp well that runs some critical watering areas on our farm. We want to have a standby generator installed, and in reaching out to generator/electrical companies, we are getting many different opinions on what we need. As a result, I have landed here to ask for advice. Here is what we have that we want to run, and the equipment that has been installed thus far:

Duke Energy 230 3-phrase power (I am told this is the highest we have available)
Pump Motor: Franklin 20hp pump model #236604 Franklin Motor Link (see three attaches pages on this motor)
Danfoss VLT AQUA Drive FC-202P18KT2ERH (see photo)
(18) Greenhouse Fans. They draw 1amp each, wired 110v.
(6) Very small irrigation timers.

The most complete quote, was a custom Diesel Generator made for this application. See attached quote.

We have gotten proposals from companies for 30kw, 40kw, 65kw with either Propane or Diesel. The issue is no consistency or agreement between electricians we have reached out to, so makes us worry about selecting a company/generator and it be to small and not work, or way overkill and burn up unneeded fuel. If there are any questions or further information I need to gather, let me know!

Thanks!

Alex the farmer

 

[theplantman]

@waross I think this is what you are asking for. Please note, we dont run everything all the time. I noted 240v power on items using that level of power. For all other power, we are 110v.

 

[waross]

Sorry. I don't have the energy to take you through basic load profiles to advanced gen-set sizing.

I noted 240v power on items using that level of power.

What you may think is 240 Volts is usually 208 Volts.
1. This can lead to a 15% difference in KVA loading.

For all other power, we are 110v.

110 Volts has been an obsolete standard for over 60 years.
If this is wild leg delta, the 120 Volt KVA loading on the gen set will be 150% of the sum of the calculated KVA loads.

Conveyor Belt

Green House Fans

This doesn't tell me any thing about the actual load.
I'll bow out and let TugboatEng deal with this one.

 

[XR250]

110 Volts has been an obsolete standard for over 60 years.

Whatever. I think this is just what some people call modern 120V. i still do from time to time.

 

[TugboatEng]

The differentiation does matter. The obsolete voltages like 460, 440, 230, and 110 are often from delta wound sources so you don't get a neutral. Grounding gets interesting as well.

 

[waross]

The differentiation does matter. The obsolete voltages like 460, 440, 230, and 110 are often from delta wound sources so you don't get a neutral. Grounding gets interesting as well.

You missed 127 Volts.
I a couple of years servicing lobster boats I saw more strange voltages than I did in 40 years of onshore work.
460, 230 and 115 are not obsolete voltages.
They are standard motor voltage ratings.
I guess they don't use high leg delta systems on boats.
High leg delta systems with a neutral are not as common as they once were.
There are still a lot of legacy high leg delta systems out there.
The open delta variant of the high leg system is still installed new for niche applications by some utilities.

Whatever

Ya, whatever.
It usually doesn't make a difference until you are specifying a generator.
I have more than once specified a generator correctly, only to have some "Whatever Expert" in the supply chain Base the KVA on a "Whatever" voltage and supply a set with not enough KVA at the specified voltage to support the load.
Another delta issue that few posting outside their area of expertise will be aware of is the restricted load division of single phase loads on three phase high leg systems.
An extreme but possible example:
Generator voltages:
L1 to X0 = 120 Volts
X0 to L2 = 120 Volts
L2 to L3 = 240 Volts.
Loading.
L1 to X0 = 3 KVA
X0 to L2 = 15 KVA
Minimum KVA adder to support 15 KVA at 120 Volts = 22.5 KVA
Adder for 3 KVA = zero KVA
Balanced three phase loads added at the calculated KVA.
It takes at least 150 KVA of generator capacity to support 100 KVA of 120 Volt single phase loading on a high leg delta generator.

Hamlet (Shakespeare) “There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy.”