Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Electrical Motors - Heat Loss

Heat loss from an electrical motor to the surroundings.

Sponsored Links

Heat Loss from Electric Motors during Operation

Heat loss from electric motors due to inefficiency:  

Size of Motor
(kW)
Efficiency
(%)
Heat Loss
(watts/kW)
0 - 2 75 250
3 - 15 85 150
15 - 150 90 100
150 - 92 80
  • 1 kW = 1.34 hp
  • 1 hp = 0.746 k W

Example - Heat Loss from an Electric Motor

The heat loss from an electric motor supplied with 10 kW can with the heat loss 150 watts/kW from the table above be calculated as

(10 kW) (150 watts/kW)

= 1500 watts

= 1.5 kW

The rest of the energy

(10 kW) - (1.5kW)

= 8.5 kW

is output mechanical energy. 

If the motor and the mechanical equipment connected to the motor is in the same room - or enclosure - all electric energy supplied to the motor will convert to heat and temperature increase in the room.

Heat Loss from an Electric Driven Device to a Room

The heat transferred to a room or enclosure depends on the location of the motor and the driven device related to the room. 

  1. motor and driven device in the room - all energy to the motor is at the end transferred to the room (heat loss from the motor and frictional energy from the driven device)
  2. motor in the room and device outside the room - only heat loss from the motor is transferred to the room - frictional energy from the driven device is lost outside the room
  3. motor outside the room and device inside the room - frictional loss from the driven device is transferred to the room - energy loss from the electric motor is lost outside the room
Nameplate Rating
(hp)
Motor Efficiency
(%)
Heat Loss to Room Air
(Btu/hr per rated hp)

Load Calculator!
Motor in Room
Driven Device inside Room
Motor in Room
Driven Devise Outside Room
Motor Outside Room
Driven Device inside Room
0 - 1.5 0.80 2542 508 2034
1.5 - 12.5 0.85 2542 381 2161
12.5 - 0.90 2542 254 2289
  • 1 Btu/h = 0.293 W 
  • 1 horsepower = 2542 Btu/hr
Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

3 10

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more