You still don't get it. I had accepted your analysis below on the basis that resonance occurs. My analysis method using your Rmec and the appropriate coil inductance agrees with this. How many times to I have to repeat that before it sinks in? It is obvious that this requires a different mechanical impedance than that given by Berenak's models using your other data. That is the inconsistency- not the calculations.
As for your use of Eq.3.60 , I correctly said that is wrong
You said: "Now to eq. 3.60, note this is of pure mechanical
You are taking BlI =BlE/Ze where Ze is the input impedance Zcoil
+(Bl^2)/Zmec So far so good
Now you add (Bl^2)/Re to both sides to get BlE/Ze+(Bl^2)/Re =(Bl^2)/Re
+(Zm+Zl) which is questionable to say the least. Assuming that you made a typo and meant to say
BlE/Ze+[(Bl^2)/Re]U =[(Bl^2)/Re +(Zm+Zl)]U you have a correct but rather useless expression of the form that if 2 =2 then 2+2 =2+2
You then take a completely imaginative jump based on wishful thinking rather than any analytic process to get BlI=BlE/Re which leads to (1.41*11.01)/7.09 =11.01*0.172 OR 2.192 =1.894 ???????
Do you wonder why I say that you are wrong.?
The only way that BlI =Re is when Ze =Re which corresponds to the blocked rotor condition where U is 0, and inductance is negligable. A blocked speaker isn't of much use.
Note that the Ze in Eq.3.59 is the coil impedance (Re+jwL) and Zm+Zl in Eq.
3.60 is the actual mechanical impedance.
Note that, in your evaluation of the mechanical equation you forgot the electrical equation (3.59) E =ZcoilI +BlU You cannot take Eq.3.60 in isolation as the electrical and mechanical sides are coupled. Solve the two equations together as I did. Repeated below for negligable inductance.
"Eq.3.59 E=ZcI +BlU where Zc is the coil impedance leads to I =(E-BlU)/Zc Ignoring coil inductance: I=(E-BlU)/Re
Eq.3.60 0= -BlI +ZmecU {or BlI =ZmecU }where Zmec =Rms+2Rmr
+j(Xmd-1/wCms) is the open circuit mechanical impedance (I =0 or Re =infinite) {which Berenak calls Zm+Zl and the Zm is NOT the Zm of Chapter 7.}
Substitute for I in 3.60 to get BlI =Bl(E-BlU)/Re =ZmecU
or BlE/Re-(Bl^2)U/Re =ZmU
(NB BlI = BlE/Re -(Bl^2)U/Re --definitely not BlE/Re)****
giving BlE/Re ={(Bl^2)/Re +Zmec}U or U ={BlE/Re) /{(Bl^2)/Re+ Rms +2Rmr +j(Xmd-1/WCms) } which is Eq. 7.1
Surely you can do better with regard to a bit of elementary algebra. It also might be a good idea to follow Berenak's sequential development leading to Eq.7.1.
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N
Northstar
Look who's talking, after refering to sophomoric and 8th grade levels.
Disingenuous. Proper checks are provided following the analysis. Just show an error in the analysis or stop your childlike nit-picking of it. You are a sore loser.
You imply a discrepency in my data. Please give the values you have for these, and show any discrepency. L was ignored early on, as it must be to agree with Small and Beranek in some areas. Note the sentence directly preceding eq.7.1 where Beranak states "neglecting w^2L^2 compared with (Rg+Re)^2". Did you not read this, or did you read it but find it favorable to ignore it. Which is it? Apparentyly you do know that L cannot be neglected in the overall picture.
I have used Ze as real from the start: Pin=(E^2/Ze)-(I^2Re)=Pmec=0.0328 watt. It took you quite a while to ask if Ze was real. Why was that?
Bull. You kept harping until I send the speaker to an independent lab for spec verification at my expense. You are just a sore loser.
No. You stated input power as [v^2 (Rms+2Rmr)]+(I^2Re). Correct input power is E^2/Ze as proven by my analysis. This is your *fundamnetal* error, unrelated to any data. You have tried to wiggle out of this before, in attempts to rewrite history, but to no avail. So what wiggling approach do you want to use this time?
No. Please show where 2.4 was given by me as Rmec. You cannot. This incorrect magnitude has been espoused only by you.
Again, look who's talking.
You don't know the half of the "what ifs" Pal.
I told you it went beyond what Beranek and others dealt with, and it went over your head. This does not mean they were incapable at all. It means it goes into aspects of the mechanical they bypassed and went directly on to the acoustical as Pa=v^2*Rmr for example. Your adamant and closed-minded approach has not been conducive to approaching this.
Disingenuousness, otherwise you are in denial or plain dumb, and I cannot believe the latter. My analysis clearly explains Rmec in simple basic accepted expressions. Answer this please: Why do you not see as "explanation" that Rmec=Pmec/v^2 when it is just a rearrangement of the basic electrical power equation P=I^2*R in mechanical analogy form as P=v^2*R, then Rmec=Pmec/v^2 ? This should cool you down a bit about explanation for Rmec.
Look who's talking about belated - - - took you over a year to accept Pmec=Pin-Pheat in correct form as related to a loudspeaker motor.
Your comment is inappropriate anyway, as some equations by Beranek and others ignore L, while it must be used in the overall picture. One either uses it or does not to get agreement with these authorities in some areas. You need to join the club, Pal (admittance is free, but does require a little consideration to detail).
Yes I do have IMO, however what I expect is open-mindedness and lack of sophomoric comments. As to a rougher ride - I expect a ***much*** smoother ride due to meeting with better understanding and respect. Absolutely and beyond doubt.
No. You are the one who misjudged both input and mechanical power, two of the most basic parameters.
Then accept Hallidays eq 7.47 for what it is. P=F cos angle v = BlI cos angle v = 0.0328. This is what I mean above - you either cannot or otherwise you refuse to rationalize the basics.
Playing "Devil's Advocate" to get me to explain things further down the road, when you do not accept basics that are discussed presently (and that lead to that down the road) such as P=F cos angle v = BlI cos angle v = 0.0328 is pertinent or that Rmec=Pmec/v^2 is "explanation" for 9.955 will not work. One does not get cooperation in this manner.
BTW what about your error re coil inductance, where you stated: "The value I got was 0.000051 henries" off by a factor of over 35? I notice you don't want to address that. Why is that?
Again, you assume with your close-minded attitude. Too bad.
No. I *know well* why you say that. Lack of understanding.
Mr. Kelly with all due respects (which are damned few, considering your nasty ongoing attitude), you are not considering things that should be considered, and I will not disclose those here. I had considered offering to do so privately, but I am now convinced this would not be a pleasant or desirable endevor. In summary, you closely approach being an arse (within smelling distance) with your "elementary algebra" remark which is based on your own ignorance.
The bottom line is that your analysis is wrong, and mine is correct. Otherwise point out any part of mine that is in error and be done with it. Just do it, OK? OK????? All your arguing above just appears as a red herring and smoke screen for your errors.
Northstar. email snipped-for-privacy@hotmail.com remove the high card to reply.
D
Don Kelly
----------- Please note that I did, repeatedly, accept this analysis. Can you not read or is your venom getting in your eyes? Your checks are on the arithmetic only.
--------------------
------------- Rms =1.57 2Rmr =0.83 sum =2.4 wMmd +2Xms =wmmd=35.91 Re=7.09 Cms=0.00025 Rg=0 w=1278 (203.4Hz) E=1.41 (and, as you earlier indicated- L was ignored)
The Zmec using this data was given to you repeatedly and my original analysis used this data. It was laid out in detail for you. The results for Zin =8.23 based on a current magnitude (calculated) of 0.1714 agree within accummulated data errors and well within with the "best calibrated error" of the Fluke 189 on the AC current range (see the Fluke website). However, I re- invite you do go over this analysis in detail- based on this data (which you provided )- and find any errors in theory or calculation. So far you have not., Until you do, you have no basis for saying that the results are incorrect. You can start with Eqs.3.59 and 3.60 or use any of the models shown by Berenak in Figures 7.2 to 7.4.
Now as an alternate approach:
Using the measured values of E, I , U that you gave to get Ze, Re and Zm magnitudes, and making NO a-priori assumptions whatsoever about phase- the results checked with the previous results that you didn't like. In neither of these did I consider inductance. My results with either set of data are consistent with no surprises. You are free to go through them in detail as they were given to you in detail.
However, there is a slight problem if inductance is negligable. Please note that while the primary resonance is between Mmd and Cms, the secondary resonance, if it exists, is between L and Mmd. No inductance means no secondary resonance. (see Eq.7.16). You can't have it both ways -negligable inductance and resonance at 203.4Hz.
----------- Actually I asked quite early on when I disagreeed with this.
--------------
---------- I didn't ask you to send the speaker to an independent lab and you certainly have not given me any of those results. You made a claim, after a consderable time, which was contrary to earlier claims.
-------------- Real power in general is E^2/Ze cos (angle of Ze) IF AND ONLY IF Ze is real, then your power input is correct. (this is basic circuit theory)- If not, E^2/Ze is NOT the power input. I am not rewriting history or distorting circuit theory. Historically, in terms of this discussion, the concept that 203.4Hz is the resonant frequency is quite recent. Prior to that, no statements were made to indicate that and, in fact you did say that (incorrect in the context) that Re/Ze was the cosine of the angle between E and I.
The point that you missed is that for resonance then there must be inductance such that wL =Xmot in order that Ze be real. I did the same analysis as I did before (and you rejected out of hand) using this fact and also using a mechanical resistance of 9.955 rather than Rms+2Rmr =2.4. The only changes that I made were in adding the inductance and changing the mechanical resistance as above. No changes in calculation procedures or theory were made. I did not use 7.1 to do this as .Berenak's 7.1 as written will give the wrong answer using your data. It gives: [(1.41*11.01)/7.09]/[17.1 +9.955 +j31.45] leads to a magnitude of U =0.0528. Correcting 7.1 to account for inductance (using Zcoil in place of Re) gives the U=0.0574
------------- >
------------ Rms =1.57 2Rmr =0.83 so Rms +2Rmr =2.4 This (correctly) does NOT include (Bl^2)/Re as it is the mechanical/acoustic resistance. This is the resistive part of the "open circuit mechanical impedance" (refer to Berenak 3.60 or to Kinsler ) . We have been over this before. How many times does it have to be said?
-------------
------------- Then you are saying that their models are incorrect. Is that it? You are effectively saying that they haven't accounted for all the mechanical resistance- essentially also implying that there is no point finding or using Rms as it is useless as it is swamped by this mysterious resistance. I wonder why Berenak even bothered with Eq.7.1 as it is based on 7.2 which is, apparently incorrect as it omits the mysterious added resistance. I note that Rmr =0.43 agrees with Eq.7.9 so that IF Berenak is right and You are also right, then your given value of Rms must be incorrect. I do expect errors in these values due to measurement problems and assumptions/approximations but 1.57 vs 9+ is a bit over the top. Since the mechanical elements do affect the velocity of the speaker, their incorrect models then must generally give the wrong values for Pa and it is just coincidence that they do give the correct velocity in this case. Do you really think that Berenak, Kinsler and others would ignore such an obvious difference and choose to use only Rms+2Rmr?. Do you think that such errors would be accepted as gospel for the last 40 to 50 years?
----------
----------- Where do you get the idea that I don't see that.? In Now it is necessary to determine what Rmec really is. You say that it is not Rms+2Rmr. so Pmec is not (U^2(Rms+2Rmr) - Ok- fair enough if you have some sort of reasonable explanation for your value of Rmec- that is why does it exist?- what is the physics behind it? If you can do this, you have, as I said, the basis for a refereed journal paper to show the gurus what they have missed. However that will take a better physical knowledge than you have shown so far.
-----------
*Bullshit*. Right from my very first analysis (not a year ago but it feels like it), I used this. I quote: "Pin=0.2162 watts (based on calculated I =0.1714 @26.56 degrees) I^2Re ==0.2082 Pin-I^2Re =0.00791 watts =Pmec loss +Pacoustic"
This is something that is true for any motor and something that I have known long before corresponding with you.
I also followed tthis with "Check:
2.4U^2 =0.00791 watts OK"
-------- . Berenak is not afraid to use approximations where they are valid-and to avoid them whrere they are not valid. I haven't omitted detail. It is not I who stated that L was negligable.
--------
------------ Wishful thinking- I have been kind and very patient.
-------
--------- Note that you left something out of Halliday -typo? Also note that I dealt with that- P=|F|*|U|*cos (angle between F and U) or P =(11.01*0.172*0.0574)cos (angle)=0.109*cos (angle) Note that when I use the angle of 85.8 degrees, the result is
0.109*0.0732=0.0080 If I used an angle of 0 the result would be 0.109 Calling on Halliday to justify your results doesn't work as his expression using your results agrees with your values and his expression using my results agree with my values. Hence neither of us can call on his expression to make a point. I explained this before. You apparently don't want to read what is in front of you if it is questioning your statements. Halliday's expression is analogous to P=EI cos (angle between E and I). So F=ZmecU so FU =Zmec(U^2) and FU cos (angle) =RmecU^2. So what is new? This is material in a first circuits course.
------------
------- Why are you so hung up on trivialities? Given a Pmec and a velocity, Rmec falls out. Given a different Pmec and the same velocity , another Rmec results.
The non-triviality is that if Rmec =9.955 then there is some physical dissipative load there is a physical reason for it- suspension, air resistance, other damping terms - what? You have no answer and neither do I. If 9.955 is correct and Rmr is correct then Rms=1.57 is incorrect or there is something that no one before you has foud worth reporting. Find the *why* for the 9.955 value that you have found. Also find the *why*for the fact that Xmec is lower than Xmd-1/wCms although this may? be errors in the Mmd and Cms data.
------------
---------- No desire to not address this - I gave you credit for understanding what I did. Sorry.
Ignoring inductance I got Zin =8.23 ohms- which is the main disagreement in external data that I had with your values (relating to I=0.1714 vs 0.1720 [+/- (0.75% of reading +5 least significant digits)] I then decided to find out what L was needed to get 8.198 ohms all other parameters unchanged. This is the source of this value- it is not the inductance needed to make Zin real. It is the inductance to make Zin =8.198 ohms. It's effect on the output velocity and any power was negligable. This is a "what if" exercise that only took a minute.
-----------
------ See below- It appears that disagreeing with you is a sign of close mindedness. It is if I had done waht you have done- simply saying "wrong" without presenting any justification. I did present a justification and analysis (which is not new) which is contrary to what you were saying. Did you bother to go through it or are you again going to dismiss it out of hand with no justification? However pleas try to go through the material below>
----------- Cop out again. I understand quite well- you don't know what you are doing when it comes to simple algebra. You talk about close mindedness- tell me what is wrong with what I said. I really would like to know. If you can't explain it rationally then say so. BlI =E/Re-[(Bl^2)/Re]U and not BlI=E/Re as you have claimed. That is clear. You apparently did not try or are not able to follow the material below (so what is new)
----------
---------- As your algebra is wrong- it is not my ignorance.
--------------------
-------- You have not even attempted to show where I have "gone wrong" based on the data that you gave me. If I am wrong- show me as I have repeatedly asked. It does lead to a different result as it does not lead to Ze being real or resonance being present.
Using the same analysis and theory, I can confirm your results using Rmec =9.955 and accounting for inductance. How many times do I have to say that? I have said that, on the basis of magnitudes of Ze, I ,Re and U as measured and assuming resonance- your values are correct.
Fact: Berenak's model, using the data that you first gave me, does not agree with your results.
Fact: Including sufficient inductance, with the above data, to get Zin =8.198 doesn't agree with your results except for magnitudes of I, Zin and U.
Fact: including sufficient inductance to get resonance, with the other data remaining the same, doesn't give your results.
Fact: Using sufficient inductance to get resonance and also setting Rmec = 9.955 DOES get your results which confirms your analysis as done (as well as my analysis methods).
Final Fact: On the basis of this, since the calculation method and the model was the same in all cases except for the changes indicated, your results do not agree with the results from the data that you gave me.
The conclusion is that either there is something missing in Berenak's models (which you apparently believe without having any physical basis to say that) or some of your data is wrong. Your choice.
I'm out of here so don't bother to reply unless you have someting more substantial than what you have presented up to now.
N
Northstar
snip
Good riddance of sophomoric level ability and disingenuousness.
Northstar
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