Heat produced by electric motors
Heat produced by electric motors
(OP)
Looking for info on calculating the heat produced by electric motors of various voltages.
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Heat produced by electric motors
|
Heat produced by electric motorsHeat produced by electric motors(OP)
Looking for info on calculating the heat produced by electric motors of various voltages.
Red Flag SubmittedThank you for helping keep Eng-Tips Forums free from inappropriate posts. Reply To This ThreadPosting in the Eng-Tips forums is a member-only feature.Click Here to join Eng-Tips and talk with other members! |
ResourcesWhat is rapid injection molding? For engineers working with tight product design timelines, rapid injection molding can be a critical tool for prototyping and testing functional models. Download Now
The world has changed considerably since the 1980s, when CAD first started displacing drafting tables. Download Now
Prototyping has always been a critical part of product development. Download Now
As the cloud is increasingly adopted for product development, questions remain as to just how cloud software tools compare to on-premise solutions. Download Now
|
RE: Heat produced by electric motors
RE: Heat produced by electric motors
We are not like this. Not normally. But sometimes.
What have you found so far? What motors are you talking about? There are so many types. Are they DC, AC, small, large, asynchronous, synchronous, single phase, three-phase, open, enclosed, ventilated? You need to reformulate your question before you can expect a decent answer.
Gunnar Englund
www.gke.org
RE: Heat produced by electric motors
RE: Heat produced by electric motors
These motors run about 8 to 10 hours a day.I was hoping there is a formula which would be a standard in heat calculations.
RE: Heat produced by electric motors
Most motor manufactures list efficiency at 1/2, 3/4 and full load.
RE: Heat produced by electric motors
The only way to be sure is get the motor manufacturer's data on each specific motor. If that is impractical (and it usually is), the rule of thumb that my HVAC friends use is to assume 75% load on each motor, and 85% efficiency. This is a gross generalization of course, but if you are calculating heat losses into a building for AC load calcs, that represents a reasonable compromise. The motors that are running at higher loads will have slightly lower loss percentages but more overall power to begin with, and lightly loaded motors have higher loss percentages but lower overall power.
So how you would do that is to convert each motor HP to kW (746W/HP), multiply by .75 for loading, then again by .15 for losses (85% efficiency), which will give you watts loss (heat rejection) into the environment. From that you can calculate BTUs if necessary.
As a side note to this, if it is a new installation, chances are the motors will need to be energy efficient designs so the "guesstimate" efficiency at 75% load can be higher, probably around 87%.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Heat produced by electric motors
RE: Heat produced by electric motors
take the centre height (in mm)and divide by 100.
ie for a 710 centre height, expect 7.5kW dissipation.
Its the right ball park for medium machines - I've checked a couple some years ago. Not sure how it would translate to fractional horsepower machines though
Richard
RE: Heat produced by electric motors
This 'formula' is rather strange...
Motors of 710mm shaft axis height may have output of several MW, with total losses well over 100 kW (which mean heating of surroundings - unless the losses are carried away by cooling medium, eg. water).
RE: Heat produced by electric motors
RE: Heat produced by electric motors
yes you are correct, I should have stated that this is the heat from a TEWAC (water cooled) machine. I was eating my lunch when i responded and didnt fully absorb the question. Having taken blinkers off now,, i realise that my formula is not much use for totally enclosed machines as all the losses have to find their way through the frame. sorry to have confused you