Two possibilities:
1. You make a mistake somewhere in the measurements;
2. The two cores differ in quality resulting in the difference in inductance (I presume there is no airgap which might be responsible).
The different winding techniques will not influence the inductance because this is a function of number of turns and core; only difference should be the capacities, and that will show up while doing HF measurements.
Yes, but I measured both OPTs with the same gear and got very different result...
Do you think that the two winding style (with the same turns) has different self resonant frequency? I mean the normal winding and the progressive winding.
What is the best way to measure the inductance at 50hz?
I have scope and signal generator.
Tyimo
Do you think that the two winding style (with the same turns) has different self resonant frequency? I mean the normal winding and the progressive winding.
What is the best way to measure the inductance at 50hz?
I have scope and signal generator.
Tyimo
Now that I understand that you did not do the measurements with the appropriate gear I tend to say 1. Yes.
Please note that silicon steel core material should be measured at frequencies at which it is supposed to be "active", that is around 100 Hz, with dedicated L meters.
And then it merely gives you an indication of what is really going on as especially with silicon steel cores inductance varies with frequency and signal amplitude.
Ther is a very big problem with the progressive wind!
This technique kills induction!
The back and forth field lines cancel each other out.
I got only the quarter of induction than with normal winding.
Tyimo
As other said, this is not possible, assuming we are talking about what is usually thought under 'progressive winding'. In this technique the turns (NOT windings) are not packed around the core linearly (perhaps with several layers resulting as the turns are packed around the whole core magnetic length), but rather N number of turns is placed next to each other, then M number of turns are placed right over the previous N ones 'backwards', then the process is repeated untill all turns in a winding are wound. M must be less than N. For instance, if N was 10 and M was 5, turns 1-2-3-4-5-6-7-8-9-10 would be wound, then turn 11 goes over 10, turn 12 over 9, turn 13 over 8 turn 14 over 7, turn 15 over 6. Then the process is repeated so turn 16 goes over 15, 17 over 14, 18 over 13, 19 over 12, 20 over 11 and 21, 22, 23, 24, 25 go over the bare core, etc. The total number of turns wound is the same, all in the same magnetic direction, but there are no discrete layers. N andm M need to be calculated so that all the turns for each winding end up in one full magnetic length of the core, i.e. one full revolution of the toroid core on the winding machine. There is no difference in inductance, but the inter-winding capacitance is much lower.
In response to your other question, I have done several prototypes of toroid OPTs, and settled on one final build. That one is not 'the ultimate' but is a good compromise resulting in reasonable work hours on the winder and manipulation costs, and the results are very good.
It should be noted that neatness of the work pays off - quite directly, it affects the leakage inductance the most. Windings must be placed precisely on the cor, with no bunching, no gaps. If you must make a gap for wire leads and taps, be sure to align the following layers precisely so that they also have gaps in the same place. This can be a problem on toroids as the rubber driver wheels that turn the core on the winder can get stuck in the gaps resulting in uneven winding.
When you're into transformers buy an LCR meter, it's kind of basic equipment; you don't need laboratory quality for normal checkups.
I tried to find one, but didn't seen anything what would measure under 400Hz and over 20H.
Almost bought this:
http://cgi.ebay.com/ws/eBayISAPI.dl...hZu5ddM%3D&viewitem=&sspagename=STRK:MEWAX:IT
Almost bought this:
http://cgi.ebay.com/ws/eBayISAPI.dl...hZu5ddM%3D&viewitem=&sspagename=STRK:MEWAX:IT
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the easiest thing to do to measure at lower frequencies is to use line voltage through a variac. Place an ac ammeter in series and then you can calculate the impedance. If done at 50 or 60hz the impedance will be predominantly inductive in nature so dividing the Z by 2piF nets you the L
Say with 100V across the winding you get 10ma of current. 100/.01= 10,000 ohms impedance. 10,000/2/3.15/50=31.8hy's
dave
Say with 100V across the winding you get 10ma of current. 100/.01= 10,000 ohms impedance. 10,000/2/3.15/50=31.8hy's
dave
LCR4080 can't measure inductance lower then 0.1H, therefore, its impossible to check with it leakage inductance.
I would recommend very old Russian E7-11. It could measure:
Inductance: 0.5 uH - 1000H (at fixed frequencies 100Hz & 1000Hz from internal generator, or 100Hz - 5KHz from external generator);
Resistance: 0.1 Ohm - 10 MOhm;
Capacitance: 0.5 pF - 100 uF.
Additionally, it can measure inductance with DC BIAS 0 - 30mA, Q factor of inductors, and tangent loss of capacitors.
Its heavy, bulky, cumbersome to use, but it uses real bridge and military-grade critical components with 0.3% tolerance.
Its low-ohm limit allows to check, for example, resistance of secondary winding of output transformer. I have a software which can calc it for EI/D2C or toroid (based on geometry, wire parameters and winding layout), but it always good to know what real numbers are.
I think you can find it on flea market for something close to nothing. The only problem with this device that you may need a professional specialist who can check, repair & calibrate it if necessary.
I would recommend very old Russian E7-11. It could measure:
Inductance: 0.5 uH - 1000H (at fixed frequencies 100Hz & 1000Hz from internal generator, or 100Hz - 5KHz from external generator);
Resistance: 0.1 Ohm - 10 MOhm;
Capacitance: 0.5 pF - 100 uF.
Additionally, it can measure inductance with DC BIAS 0 - 30mA, Q factor of inductors, and tangent loss of capacitors.
Its heavy, bulky, cumbersome to use, but it uses real bridge and military-grade critical components with 0.3% tolerance.
Its low-ohm limit allows to check, for example, resistance of secondary winding of output transformer. I have a software which can calc it for EI/D2C or toroid (based on geometry, wire parameters and winding layout), but it always good to know what real numbers are.
I think you can find it on flea market for something close to nothing. The only problem with this device that you may need a professional specialist who can check, repair & calibrate it if necessary.
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