Toroidal Chokes

[denny9167]

I know of several companies that distribute toroidal power transformers at a reasonable cost,I have yet to find any that also make stock power chokes using a toroidal core,any suggestions.

[Jeb-D.]

Originally Posted by denny9167

I know of several companies that distribute toroidal power transformers at a reasonable cost,I have yet to find any that also make stock power chokes using a toroidal core,any suggestions.

Toroidal is not a good choice for a choke. They don't handle DC well.

[TheGimp]

Speaking of alternative chokes, has anyone ever evaluated blasts for florescent bulbs? I've got a small one for a circular 22W lamp and it is rated at .35A. I plan on taking it to work Monday and measuring the inductance. I'm guessing this one will only be a Henry or so, but they might be an inexpensive alternative.

Has anyone ever evaluated them?

[Kashmire]

Toroid chokes are awesome. I've used toroid chokes as the CCS (constant current source) for the Pass Zen amps, operating a couple amps (see one of the threads here). I used the Amveco chokes. They have some standard catalog items starting at 5 Amps DC to 60A DC. This was a little too high for me, so I called them and ordered 4 chokes at 2.5A 120mH. These worked great. The various core sizes are based on Watt-hours of inductive energy storage, so you can order whatever current/inductance you are looking for. For me, 2.5 Amps is perfect, because it suits my Zen, Aleph, and First Watt power supplies perfectly.

My dual-mono Zen setup used four chokes. Each channel used one choke in the power supply (in a "pi" filter, or CLC configuration) ahead of the capacitance multiplier, and one choke as the CCS. The frequency performance was excellent, and the power supply was dead quiet with 120mH running at 2A.

Toroid chokes contain their magnetic fields (low leakage), are very compact for their inductive energy storage, efficient, have great DC performance, and excellent frequency characteristics.

[denny9167]

I should have clarified something, I will be using the choke in a tube power supply,I need one in the order of about 10H.

[kevinkr]

Originally Posted by denny9167

I should have clarified something, I will be using the choke in a tube power supply,I need one in the order of about 10H.

I would talk to Amveco to find out whether or not they can build a toroid choke that can handle your application, the key is to make sure that the core never saturates in normal operation. I doubt there will be any significant advantage parametrically speaking compared to a conventional EI choke, except that magnetic fields should be better contained again as long as the core doesn't saturate. Form factor might be an advantage in your application, the probable higher cost compared to an ots choke is a potential disadvantage.

[TheGimp]

The ballast ended up being 0.35H, and when I checked at the local hardware store ballasts were more expensive than conventional chokes. Scratch that idea.

[bequerel]

Try Plitron :-)
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