Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Current in Induction heating (Peak or RMS)?
Posted 23 ago 2012, 08:39 GMT-4 Low-Frequency Electromagnetics, Heat Transfer & Phase Change Version 4.2a 6 Replies
Please login with a confirmed email address before reporting spam
When solving using the Induction Heating solver, can anybody confirm if the "Current Excitation" in the "Coil Group Domain" is peak or RMS? I have a suspicion that the value to be specified is the PEAK value, since the expression for the coil power has a factor of 1/2. Can anybody confirm?
Abhishek
Please login with a confirmed email address before reporting spam
Please login with a confirmed email address before reporting spam
which solver do you use ? if it's the harmnic or frequency domain, indeed you define an (0-peak) amplitude excitation, and then usually the average power has a factor 1/2 ... no ?
The best is always to make a very simple model you can write out analytically, to validate your undersanding of COMSOLs behaviour (and this before you validate COMSOL's results ;)
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
I am using the "Induction Heating" Model as given in COMSOL 4.2a. I think it uses Harmonic analysis for the ACDC part.
Any idea if the Coil Current to be specified is the peak or rms?
Regards,
Abhishek
Please login with a confirmed email address before reporting spam
for the harmonic solver the forces you apply are the amplitude (0-pk) of the "sinus" type harmonic excitation you desire
you have then also some rms value outputs, check the equatoions of COMSOL and the doc
--
Good luck
Ivar
Please login with a confirmed email address before reporting spam
Thanks! .. I also thumbed through the induction heating example again (www.comsol.com/showroom/gallery/148/), and I noticed that the "Current Amplitude" is mentioned. So as you said, the peak current needs to be specified.
Also, I noticed that the coil voltage output can be obtained by multiplying the specified current with the coil impedance. Just for an example (from one of my analysed cases):
Coil current (Specified): 250 A (i.e. since no phase is mentioned, so its equivalent to 250exp(0*i), i.e. 250 + 0i A)
Coil impedance (Ω): 0.0225+0.76284i (As output from comsol)
Coil voltage (V): 5.62594+190.71109i (As output from comsol)
As we can see (250 + 0i)*(0.0025+0.76284i) = 5.625 + 190.71i V (same as comsol output)
Being am a mechanical engineer, I could not make much sense of the theory manual :-), but thanks for your help :-)
Regards,
Abhishek Basak
Please login with a confirmed email address before reporting spam
on my side being a Physicist and Systems Engineer I have learned most of my systems approaches by studing the manuals for all items I encounter, in the beginning you feel overrun, but after some years you get used to it and you catch more than what you think, and its generally very useful ;)
--
Good luck
Ivar