Heat Loss in MCCs?

[dudikr2]

Have to figure out the heat loss in MCCs for some HVAC guys. The disconnecting device is 600 amps, but the buses are rated up to 2000 amps and 4.16 kV. The motors I'm working with are 500 hp. I was told it was around 0.5% heat loss. Here are some references I'm looking at. I can't post the SKM schematic on here for confidential reasons. Any help would be appreciated. I am a new engineer and am trying to learn. A lot of guys taught me on this website yesterday about heat loss in transformers, now I'm working on MCCs.

https://solutionone-qa.schneider-electric.com/cbm/HelpFiles/0210e/chm_0210_016_ndx0000024605.htm

also,
Motor Control Centers

Section : 500 Watts per section
Low voltage starters size 00 : 50 Watts
Low voltage starters size 0 : 50 Watts
Low voltage starters size 1 : 50 Watts
Low voltage starters size 2 : 100 Watts
Low voltage starters size 3 : 130 Watts
Low voltage starters size 4 : 200 Watts
Low voltage starters size 5 : 300 Watts
Low voltage starters size 6 : 650 Watts
Medium voltage starters size 200 Amp : 400 Watts
Medium voltage starters size 400 Amp : 1300 Watts
Medium voltage starters size 700 Amp : 1700 Watts

 

[kwired]

I would think thermal vs electronic current monitoring devices will have different impact, but still on top of conductor and contactor heating contributions.

 

[dudikr2]

So are there any suggestions as to the percentage heat loss? Maybe some sort of table for me to use.

 

[dudikr2]

I believe i found it. Page 11 in this document there's a table.

http://static.schneider-electric.us... Voltage Motor Control Centers/8998CT9701.pdf

 

[Jraef]

I would think thermal vs electronic current monitoring devices will have different impact, but still on top of conductor and contactor heating contributions.

Heat from a thermal element, such as a bimetal overload relay, is typically considered to be 9W per phase. I know because I once submitted an energy rebate request for changing out an entire MCC with 400+ starters to solid state OL relays, based on eliminating that heat losses in all of those heater elements. The utility (BC Hydro) wanted proof, so we conducted a study. Didn't amount to much money back from the utility, but it was kind of a fun exercise. Bottom line though, the watts loss values in those estimates likely include that.

 

[Cow]

I see a list for your starters, when do you start tackling soft-starts and VFD's?

 

[Julius Right]

See for instance :
https://www.mne.ksu.edu/people/personal/white/pdf-files/heat2.pdf