Heat Loss in MCCs?

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dudikr2

Member
Location
New York, NY
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

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

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
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.
 
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