Generator sizing for a 3 phase ice maker

[skkippboo]

I have a 3 phase ice machine that I would like to run on a generator, completely separated and totally isolated from any other electrical system.

My voltages read 208V on the high leg, 120V on the other two, 240V between any of the three legs.

My machine pulls just under 50 amps on each leg measured by an amp meter.

How many kilowatts do I need to run this machine?

 

[iwire]

Skip, as you are not an electrian the forum rules prevent us from helping you install this unit but we can help with your sizing question.

You should look at the nameplate information on the ice maker and post that info.

But going with what you posted the units running load is about 20 KW or 20,000 watts.


240V*50A*1.73=20760W/1000=20.76KW

But that assumes the unit was drawing it's max when you took the reading and does not take into account the needed start up current or the units power factor.

 

[skkippboo]

Thank you for your help in the calculation, that is what I calculated as well but just wanted to check to be sure. As far as installation, I have enough experience working with these machines to be able to install the electrical connections. Thanks again.

 

[kingpb]

You better take into consideration the last sentence in Bob's post. Continuous power requirements and starting power requirements are two different things, and generators rated close to the load are sensitive to this.

 

[dbuckley]

You better take into consideration the last sentence in Bob's post. Continuous power requirements and starting power requirements are two different things, and generators rated close to the load are sensitive to this.

Thirded.

Managing inrush currents with a genset is mostly about the prime mover being able to step up to provide the necessary grunt to keep the generating rolling at 1800RMP or whatever. If the engine slows, even a bit, then the genset management will shut it down. Inrush and step-change handling is rarely an electrical problem. Lower cost generators are usually tighter on available grunt.

I observed a generator test at installation a few years back; the genset was rated at 220KW continuous. The bloke set his loadbank to 220KW, pressed the green button and the genset stopped dead. The genset could produce 220KW, but only if you started at something like 100KW, then took jumps up to about 180KW and then finessed it from there to 220KW, by which time a lot of smoke was coming out the exhausts, but 220KW of heat was coming out the loadbank, and thus the device passed muster. Fortunately, the expected load was well less than the genset capability, and the largest step change was a few tens of KW..

The lesson from this is that the genset couldn't handle a step load well less than the rated output, let alone an inrush on top of the stated output.