Article View: sci.electronics
Article #21953Re: 100V Japanese products on 120V US lines
From: Bob Jewett
Date: Tue, 02 Jan 1990 17:20
Date: Tue, 02 Jan 1990 17:20
20 lines
1303 bytes
1303 bytes
> Only a small quibble: the *primary* current is what you have to worry
> about, not the secondary: since all the load current flows through both
> transformer windings, ...
Nope. The current ratio of secondary to primary is still about 5:1. It is
easier to see if the schematic is redrawn:
24V secondary
Hot,120VAC 0-------*----------wwwww------------0 Hot,~90V (or 150V!!)
| ===========
*-------mmmmmmmmmmm-*
120V primary |
|
|
Neurtal,120VAC 0---------------------------*-------0 Neutral
The load current flows only in the secondary. If you want to be safe, you
also have to worry about fuses and which side of the line is neutral.
Bob Jewett
Technical Details
Message-ID:
<65200007@hpl-opus.HP.COM>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!jewettReferences:
<3215@uceng.UC.EDU>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hpl-opus!jewett From: jewett@hpl-opus.HP.COM (Bob Jewett) Newsgroups: sci.electronics Subject: Re: 100V Japanese products on 120V US lines Message-ID: <65200007@hpl-opus.HP.COM> Date: 2 Jan 90 17:20:21 GMT References: <3215@uceng.UC.EDU> Organization: HP Labs, High Speed Electronics Dept., Palo Alto, CA Lines: 20