Hello, everyone.

This is Enta.

You're using a generator, right? lol

Well, that's only natural, isn't it?

I brought the 60-kVA unit I had just bought last month to the ground anchor job site.

On a job site, electricity is everything, after all.

How do you go about selecting that generator?

 

I'm guessing—based on experience—that 45 kVA should be enough power here, right? Or maybe 60 kVA would be enough?

I think they're making their selections along those lines.

Don't you think it would be better to turn that into a definitive selection?

 

For example, let’s consider the generator used during sprayed mortar work.

Spray Machine Motor: 15,000 W (15 kW)

Conveyor belt: 1,500 W (1.5 kW) × 2 units = 3,000 W

Measuring Instruments: Margin of Error

Sand Hopper Vibrator: 50 W (0.05 kW)

Submersible Pump: 1,500 W (1.5 kW)

Total: 19,550 W (19.55 kW)

 

Divide this 19.55 kW by the power efficiency.

The power efficiency is 0.65.

Since modern generators are highly efficient, a factor of 0.7, 0.75, or even 0.8 might be acceptable, but since you may be using a rental generator or your own equipment might be older, please use a factor of 0.65 (to be on the safe side).

19.55 kW ÷ 0.65 = 30.0 kVA

The required generator size is 30 kVA.

However, this value does not take into account the load placed on the motor when it starts moving.

This KVA value applies only when everything is operating stably.

Please use a larger generator to account for the inrush current during motor startup.

Actually, a typical spray applicator often uses a 45-kVA unit, right?

Since they don't all start up at the same time, the barrier won't come down, but please be careful—if you try to start them all at once, the generator might make a "brrrrrr" sound and shut down.

Start the generator and use the distribution panel to supply power to each machine, starting them up one by one.

Doing it all at once would be crazy lol

Please use this calculation to determine whether the power capacity of the machinery being used for the construction project is sufficient.

There’s a clear difference between knowing this and not knowing it.

It can also provide a starting point for solving problems on-site.

 

See you later.

Electricity Cost Calculator + Power Conversion Tool

I found a website that was even more convenient than that.
It automatically calculates the KVA.