Re: PM design - Simulation results far from Prototype results....

["rooom99" <kramer-b@xxxxxxxxxxx>]

Dear Tony,

Whats your gap geometry? Gap width, gap height?

Better use 1010 low carbon steel for loudspeaker magnets.
It is available without problems (check Taiwan sources).
To reduce the carbon content, you can anneal the steel.

Hope it helps....

Regards,
Hermann



--- In femm@xxxxxxxxxxxxxxx, Sven Olsen <a1greatdane@xxxx> wrote:
> Dear Tony,
> I take it we are talking about a circular airgap structure for a 
loudspeaker voice coil. You indicate 1.2 Tesla in this gap, but the 
steel pieces can very well be saturated - check with the cursor in 
femm for point properties and see what the reading are or lay a line 
contour through the steel. If you read more than 2 Tesla, there's a 
good chance your 1018 steel is saturated.
> Best regards
> 
> 
> tonyrouget <tonyrouget@xxxx> wrote:
> Dear All,
> Thanks for your help and share of knowledge...
> 
> 1)I am pretty sure about the Neo35H since I have the spec sheet and 
> it's a reliable supplier, 
> 
> however I wasn't expecting the Steel to be one of my problem..Maybe 
I 
> have too much saturation in my design..
> 
> Is 1.2T saturated for 1018 steel ?? I thought it was a bit higher 
for 
> the 1018..
> 
> Thanks for your help.
> 
> Regards
> Tony
> 
> 
> 
> 
> 
> 
> 
> 
> --- In femm@xxxxxxxxxxxxxxx, Sven Olsen <a1greatdane@xxxx> wrote:
> > Dear Tony,
> > the results I have with using femm indicates that some thing else 
> is wrong in your real world implementation. My real world results 
is 
> normaly at max 5% out from the simulations. Are you sure about your 
> quality of steel? It only takes a small lead contenst to render the 
> magnetic quality of the steel virtually useless. How about the 
> quality of the neo? You say 35N, but are you sure? There's many 
> qualities comming out of 'ping-pong land'. Is the neo fully and 
> optimally magnetized? It takes a very serius magnetizer to fully 
> charge the circuit.
> > Best regards
> > A1greatdane
> > 
> > tonyrouget <tonyrouget@xxxx> wrote:
> > Dear All,
> > 
> > First of all, thanks David for your great software!!
> > 
> > I have a quick question:
> > 
> > Did anybody already experienced any problems to relate Femm 
> > simulation results with the real world??
> > 
> > And if Yes, what could be the cause of the simulation error.???
> > 
> > In other words, I have designed a loudspeaker motor assembly with 
> > Neodymium 35 and I was expecting 1.2 to 1.4T in the airgap.
> > Confident of my design and simulation results I built a prototype 
> and 
> > could only get 0.8T Maximum in my Airgap with the Gaussmeter..
> > 
> > I am using 1018 Steel and Neo 35H. I've been inputing the tech 
> specs 
> > of my magnet and editing a new model in my library..
> > 
> > If you had already experienced simulation problems, please give 
me 
> > your input..
> > 
> > Regards
> > Tony
> > 
> > 
> > 
> > 
> > 
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