Powering Electrostatic Tweeters

[EC8010]

Originally posted by maudio
The fact that toroids have so few layers also accounts for their good frequency response, small winding height = less leakage.

Interesting. I thought the better HF response of toroids was down to the better magnetic path of the core - no sharp bends or changes in permeability to cause leakage, and therefore leakage inductance. Thoughts?

[maudio]

Originally posted by EC8010


Interesting. I thought the better HF response of toroids was down to the better magnetic path of the core - no sharp bends or changes in permeability to cause leakage, and therefore leakage inductance. Thoughts?

That has little to do with it.

Leakage is mostly caused by the fact that the different windings never share all magnetic field lines, there are always some lines that don't go through all windings and so magnetic coupling is never 100%.
This is simply caused by the physical arrangement of the windings. They can never be all in exactly the same physical plane.

The thinner the layer of combined windings is the better. Since having few layers also reduces capacitance there is a double benefit for high frequency response.

A common way to reduce leakage is to interleave the primary and secondary in several layers. But the price for that is higher internal capacitances, which reduces the positive effect on high freq response.

In fact it's possible to calculate a pretty good estimate of what leakage for a given transformer will be, based on the arrangement of the windings and their sizes. Have a look at the RDH4, there is a whole chapter on the subject.

[poynton]

Originally posted by ak_47_boy
[B............Two 120V primary 6V secondary transformers work good, that will give you a 40:1 step up............. You can run the 6V side in parelell to get a lower independence also. ............ [/B]

Originally posted by DSP_Geek


This is not the safest suggestion I've ever seen here. The transformer insulation is rated at 120 V, perhaps three times that to cover overvoltages, but 3 KV? At that point it needs better isolation than you're likely to get from a power toroid.

Find another way.

The easiest way to find out if the insulation will take the voltage is to try it !!!

Anyone have 2 transformers - 240/60v and 240/6v ??

That should give 2.4Kv on the output.



Andy

[Brian Beck]

The easiest way to find out if the insulation will take the voltage is to try it !!!

You can try it of course. But what works today might not work tomorrow. If the insulation materials pick up moisture and airborne contaminants, there can be an aging effect resulting in degradation of voltage stand-off. Also, a brief voltage peak might cause no breakdown, but sustained voltages could "punch through". Finally, once leakage starts, carbon tracking and dust attraction can make it worse and worse.