Generator Size

It all depends on the 70kVA loads. Load starting requirements? If the 70 kVA loads were all carbon comp resistors, then a 210 kVA genset would be fine. Not so if you were driving piston style refrigeration compressors. You'll need some transformers too.

What is this "telephone" device you speak of? How does one interface with it?

Absolutely hilarious!

He needs a generator that is larger than 210 kVA to be sure, since nearly any load hooked up to this will surge a bit on start.

How much larger clearly depends on the specifics of the three load devices.

If they happened to be single phase motors, that is one thing. Three phase motors or even DC motors, quite another, but I would probably start with 100% overage (420 kVA) for starters and see if that works.

You can't put silly putty back in a bottle very easily without making thin strings of it.

https://www.youtube.com/watch?v=prw0EjAl6HA

Thanks for your replies.

Just another, if the three loads are connected in single phase, direct on line because no transformers will be used. What size of genset should be considered? How to compute that one?

It is exactly the same, as specifics of the sequence of starting and the nature of the loads are STILL withheld from the forum.

It might be a different piece of equipment, now being single phase, and the rating is just the same.

How did those telephone calls with the equipment suppliers go, by the way? The forum always has opportunities for learning from subscribers that post the outcome of their deliberations.

telephone calls with equipment manufacturer - genset manufacturer will refer you to their distributor / contractors. These guys will quote you a price for installation. They are not engineers and have no idea of application theory.

That's nonsense.

<...you...> It's not needed here so there won't be any outgoing calls from this location!

They might quote the original poster, were that individual to ask, and that quotation will provide the answer to that individual's original question. However, the original poster STILL needs to discuss with the recipient(s) of the call(s) what the details of the loads are and any sequential-starting, which is STILL unforthcoming to the forum. Perhaps that individual will have a better chance with the suppliers directly.

Just because a quotation has been received doesn't place one under any obligation to purchase, and it can be a useful learning exercise that does not warrant denial.

Under those circumstances:

<unsubscribes>

The result will be the result of the telephone conversation with your vendor, you still need to allow for start up surges of each load, especially when the impedance is complex, not simply resistive.

Your question is not clear. What is meant by 3 loads, 70kVA each for 220 volts , and 440Volts?

I assume it is 3 loads of 70kVA , 3 phase 440 Volt.

Hence 3 x 70 = 210 kVA

If we consider the Generator works at 80% efficiency, then you need 262.5kVA Generator. ( 210kvA/0.8)

That would only be true if the loads were to exclude the prospect of three 70kVA motors starting simultaneously. The original poster STILL has not excluded that prospect from this forum's deliberations.

Your "information" is insufficient and inconsistent. Please describe correctly what you have/want.

...directly to equipment vendors, by telephone in the first instance.