I am confused of inductance and impedance of transformer
Is this Equation correct?
V is voltage, N is turns, Z is impedance and L is inductance
Is this Equation correct?
V is voltage, N is turns, Z is impedance and L is inductance
In ltspice, inductance is needed to set the OPT, and I need to set a OPT 2K+2K:8, how to set the inductance of prim and sec?
Looks fine to me - inductance and impedance scale as N*N.
Does the trafo seller have a spec sheet? Normally the primary (shunt) inductance is given. You then set the secondary inductance according to the turns ratio squared.
Does the trafo seller have a spec sheet? Normally the primary (shunt) inductance is given. You then set the secondary inductance according to the turns ratio squared.
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The inductance of a coil goes up as the square of the turns (N Squared).
A primary with 2000 turns will have 4 times the inductance of a primary of 1000 turns (if they are on the same magnetic core).
The impedance of a primary goes up as the square of the turns (N Squared).
If the core and the secondary are constant, and there is a proper constant load on the secondary, Then the primary with 2000 turns will have 4 times the impedance of a primary with 1000 turns.
Of course the other way to look at it is as jerrylong initially stated, the Root of inductance, and the Root of impedance; are proportional to their associated Vs and the Ns (primary inductance, impedance, V, and N) and (secondary inductance, impedance, V, and N).
A primary with 2000 turns will have 4 times the inductance of a primary of 1000 turns (if they are on the same magnetic core).
The impedance of a primary goes up as the square of the turns (N Squared).
If the core and the secondary are constant, and there is a proper constant load on the secondary, Then the primary with 2000 turns will have 4 times the impedance of a primary with 1000 turns.
Of course the other way to look at it is as jerrylong initially stated, the Root of inductance, and the Root of impedance; are proportional to their associated Vs and the Ns (primary inductance, impedance, V, and N) and (secondary inductance, impedance, V, and N).
2k+2k:8 is a 8k:8 push pull OPT.
At first you should know the total primary inductance. This value is not always given by the manufacturer, but let's assume that it is 40 H.
This is quite close to the values of Edcor and Hammond 8k PP-transformers.
Since one primary halve has 1/2 of the total number of turns, the inductance of is 1/4 of total, i.e. 10 H.
The total impedance transforming ratio is 8k:8 = 1000, then Lpri/Lsec = 1000 too.
Then the inductance of the secondary is 40 H/1000 = 40 mH.
So the 8k:8 PP OPT has two 10 H primary halves (forming 40 H total inductance) and 40 mH secondary.
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It is a AudioReserch VSi55 OPT, I have mesured the impendance of prim by connected a 8R resistor to Sec(0~8), the prim impendance is 4K(P1~P2),
the conductance of Prim(P1~B) is about 14.427H
and P2~B is about 14H, tested with 100Hz/1V
with this infomation how to set the SPICE model? or need to test more?
the conductance of Prim(P1~B) is about 14.427H
and P2~B is about 14H, tested with 100Hz/1V
with this infomation how to set the SPICE model? or need to test more?
That amplifier has 6550 tubes, so the OPT is likely 4k, not 8k.
If inductance of one primary halve is 14 H, then inductance of whole primary is 4 x 14 H = 56 H.
Since impedance transforming ratio is 4k/8 = 500, the inductance of secondary is 56 H / 500 = 112 mH.
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Thank you, here is the verification by the SIM, you can get more examples at :: View topic - Drop down transformer models for LTSpice
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In my experience of measuring transformer inductance you're better off measuring at a lower stimulus voltage or at higher frequency. So 0.1V @ 100Hz or 1V @ 1kHz. This is because the inductance is a somewhat non-linear function of frequency, rising at LF.
Its also a good idea to calculate the K value (mutual inductance) by making a measurement of the leakage inductance. Short the secondaries and measure the primary inductance, this inductance is the leakage inductance, call it LLe. With the primary inductance of LPr the K value = (1-LLe/LPr).
I am trying to sim the AudioReserch VSi55, and need a CPC5602 SPICE model, can someone post it here, or if I can find it anywhere?
You can replace CPC5602 with a 4...6 mA constant current generator. I may need some fine tune for current value to get the best THD.
It is fully sufficient for LT Spice simulation.
There is maybe an error in your schematic. One 6550 cathode is connected to GND and the other to OPT secondary.
Should it be so that both have connection to secondary ?
It is fully sufficient for LT Spice simulation.
There is maybe an error in your schematic. One 6550 cathode is connected to GND and the other to OPT secondary.
Should it be so that both have connection to secondary ?
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A couple of things I noticed about your OPT - you have the inductance as the impedance (1k5 and 8). And your K = 0.99 is showing a very high leakage inductance (1% of the primary L) so you'll be unlikely to get the full audio bandwidth out.
With LT Spice simulations and in the case that the CCS is at the cathode, you will not find any substancial difference between ideal CCS as I suggested and CPC5602.
There are several other parts in the schematic which cause 10 x more effect to THD and frequency response than this CCS.
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