Heat Loss from Electrical Equipment

Heat loss from electrical equipment like switch-gear, transformers and variable frequency drives.

Transformers

Transformers are in general highly efficient and large power transformers - 100 MVA and larger - can be more than 99% efficient. Smaller transformers - like used in consumer electronics - may be less than 85% efficient.

Heat loss for

150 kVA and smaller : 50 Watts/kVA (aprox. 5%)
150 - 500 kVA : 30 Watts/kVA (aprox. 3%)
500 - 1000 kVA : 25 Watts/kVA (aprox. 2.5%)
1000 - 2500 kVA : 20 Watts/kVA (aprox. 2%)
larger than 2500 kVA : 15 Watts/kVA (aprox. 1.5%)

Switch Gear - Circuit Switch Breakers

Low voltage breaker 0-40 Amps : 10 Watts
Low voltage breaker 50-100 Amps : 20 Watts
Low voltage breaker 225 Amps : 60 Watts
Low voltage breaker 400 Amps : 100 Watts
Low voltage breaker 600 Amps : 130 Watts
Low voltage breaker 800 Amps : 170 Watts
Low voltage breaker 1600 Amps : 460 Watts
Low voltage breaker 2000 Amps : 600 Watts
Low voltage breaker 3000 Amps : 1100 Watts
Low voltage breaker 4000 Amps : 1500 Watts
Medium voltage breaker/switch 600 Amps : 1000 Watts
Medium voltage breaker/switch 1200 Amps : 1500 Watts
Medium voltage breaker/switch 2000 Amps : 2000 Watts
Medium voltage breaker/switch 2500 Amps : 2500 Watts

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

Variable Frequency Drive

Variable frequency drive : 2 - 6% of kVA rating
Bus duct : 0.015 Watts /ft Amp
Capacitors : 2 Watts / KVAR

Related Documents

Calculating Cooling Loads - Calculating chiller and cooling tower refrigeration loads - in tons.
Cooling and Heating Equations - Latent and sensible cooling and heating equations - imperial units.
Cooling Load - Latent and Sensible Heat - Latent and sensible cooling loads to consider when designing HVAC systems.
Electrical Equipment typical Power Consumption - Typical power consumption and running time for common electrical equipment.
Electrical Motors - Heat Loss - Heat loss from an electrical motor to the surroundings.
Electrical Motors - Starting Devices - Direct-on-line starters, star-delta starters, frequency drives and soft starters.
Heat Gain from Electrical Motors in Continuous Operation - Amount of heat transferred from electrical motor to ambient room vs. locations of fan and motor.
Heat Gain from Lights - Heat contributed by lights may have major impact on air-condition systems.
Human Heat Gain - Heat gain from persons in air conditioned spaces - in btu/hr.
Indoor Temperature and Humidity Loads - Calculate sensible and latent heat from persons, lights, electric equipment, machines, evaporation from water surfaces, polluting fluids and miscellaneous loads.
LENI - Lighting Energy Numeric Indicator - Energy consumption of lighting systems
Metabolic Heat Gain from Persons - Human metabolic heat gain in air conditioned rooms.
Microwave Heating - Heating with microwaves.

Heat Loss from Electrical Equipment

Heat loss from electrical equipment like switch-gear, transformers and variable frequency drives.

Transformers

Switch Gear - Circuit Switch Breakers

Motor Control Centers

Variable Frequency Drive

Related Topics

Related Documents

Share

Search Engineering ToolBox

SketchUp Extension - Online 3D modeling!

About Engineering ToolBox!

Privacy

Advertise in the ToolBox

Topics

Unit Converters