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PS choke voltage ratings

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Posted on January 3, 2017 at 20:01:48
Posts: 273
Location: Ontario
Joined: September 20, 2007
When a choke maker such as Hammond say the voltage rating is 400v what does this mean? If I use a 400V rated choke where the B+ is about 425V is my choke going to melt? I find this puzzling because Edcor, for instance do not give a voltage rating. Thanks for any enlightenment.

 

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RE: PS choke voltage ratings, posted on January 3, 2017 at 20:26:08
Eli Duttman
Audiophile

Posts: 9357
Location: Monroe Township, NJ
Joined: March 31, 2000
That's the potential difference across the choke limit. You'll be FINE in a CLC filter. Another consideration is the HIPOT rating between winding and core, as the core is usually at chassis ground potential.

Eli D.

 

RE: PS choke voltage ratings, posted on January 3, 2017 at 20:58:18
Paul Joppa
Industry Professional

Posts: 6674
Location: Seattle, WA
Joined: April 23, 2001
It means that if you use a higher voltage, and the choke shorts out and electrocutes you, your family can't sue the maker.

To a much less exact extent, it should mean the choke is safe to use up to the rating.

There is much more to this story, but there's no way to cover all the issues in forum posts. It would take a long chapter in a good book, or possibly a whole book devoted to the issue.

 

RE: PS choke voltage ratings, posted on January 4, 2017 at 06:52:02
Triode_Kingdom
Audiophile

Posts: 5771
Location: Texas
Joined: September 24, 2006
"That's the potential difference across the choke limit."

That's not correct. The voltage rating of a choke is the maximum rated continuous DC voltage between the windings and the case. Hi-pot is a stress test intended to detect failures in the production process. It should never be used as a measure of the transformer's voltage rating in normal operation.


--------------------------
Buy Chinese. Bury freedom.

 

RE: PS choke voltage ratings, posted on January 4, 2017 at 07:39:26
sony6060
Audiophile

Posts: 677
Location: SE MI
Joined: August 8, 2014
For 25 volts over limit I would not worry about it. If the choke is insulated from ground, voltage can go higher. For safety reasons, insulated chokes should be under a chassis with a bottom plate to prevent contact.

 

choke in ground leg, posted on January 4, 2017 at 07:44:07
RayP
Audiophile

Posts: 555
Location: Maryland
Joined: June 30, 2005
Back in 2006 I posted a question about placing the choke in the ground leg and got several interesting replies. See link below.

It made me quite nostalgic to see the names of former posters.

ray

 

RE: choke in ground leg, posted on January 4, 2017 at 09:13:26
sony6060
Audiophile

Posts: 677
Location: SE MI
Joined: August 8, 2014
There is an article in one of the older 1950s ARRL Handbooks (ham radio) about negative lead choke installation. For low current applications such as a preamp it induces some extra low level noise vs positive lead choke installation.

See my response in your link under moniker Jimmy reply. That is me in early years at AA and I quoted the ARRL handbook.

 

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