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Re: [TCML] Impedance



Hi Matthew,


Use the resonant frequency of the TC.
 At resonance, In an ideal system, L1*C1=L2*C2,  XL1=-XC1, and XL2=-XC2. 


Assuming you are talking about the tank capacitor and primary coil (You don't actually say). If tank capacitor was measured as 0.02x10^-6 and the resonant frequency is 234kHz, then at that resonant frequency, (note 2*pi*f= 6.283*234*10^3= 1.470*10^6)
 XC1=1/(2*pi*f*C) = 1/(1.470*10^6*0.02*10^-6) =1/(1.470*0.02)= 1/0.0294 =34.01 ohms
now setting |XC1|=|XL1| or 34.01=2*pi*f*L
34.01=1.470*10^6*L
23.14*10^-6=L. 
The inductance of your primary. when tapped at the resonance spot, should be close to 23.14 uH. This is in very good agreement with what you have reported. Remember, in an ideal system Z(f0)=0. In a real system Z(fo)~R where R is the resistance of all the primary wiring + resistance of L1 +resistance of spark gap, while it is firing.


The only time you want to use the line frequency,( in your case 50 Hz), is to make sure that your tank cap is NOT resonant with your power transformer's secondary. In this case the XL of the transformer is very close to its impedance Z~=XL because XL>>R.So you want f=1/[2*pi*sqrt(L*C)] to NOT be close to 50.


Another thing that would make your question clearer would be consistant use of parentheses and one of the generally accepted forms of exponentiation notation.


10^-6,10^3 or 10**-6, 10**3 or 10E-6 10E3, are all clear as to intent, 10-6 or 103 are not and can lead to errors and or confusion.


Matt D.






-----Original Message-----
From: matty mcqueeney <matty_queeney@xxxxxxxxxxxxx>
To: tesla <tesla@xxxxxxxxxx>
Sent: Thu, Apr 17, 2014 6:21 am
Subject: [TCML] Impedance




Hi guys, I am having a bit of a problem finding the Impedance.. Here are my 
figures below, but I am confused if I use the AC supply frequency which is 50 or 
the resonant frequency which is 234 x103  .  Reactance of the circuit inductance

XL
= 2 Pi x Frequency x Inductance

2 PI x 50 x 0.0232
x10-3

= 7.288 x10-3

 

 Reactance of the circuit capacitance

Xc = 1/2 Pi x Frequency x Capacitance1/2 Pi x 50 x 0.02 x10-6



= 159.15 x103 ImpedanceZ= ((XL –XC) 2)0.5((7.288 x10-3 –159.15 x103)2)0.5
= 159.15 x103

Or Reactance of the circuit inductanceXL = 2 Pi x Resonant Freq x Inductance2 x 
234 x103 x 0.0232 x10-3=34.11  Reactance of the circuit capacitanceXc = 1/2 Pi x 
Resonant Freq x Capacitance1/2 Pi x 234 x103 x 0.0232 x10-6= 1591.54 kHz  
ImpedanceZ= ((XL –XC) 2)0.5((34.11 –34.00)2)0.5= 0.11 which one is the correct 
one? and for the secondary, if the Frequency is 50... would I do the same? This 
would be really helpful, Thanks. Matthew   

 		 	   		  
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