[Amps] Bridging 120v loads across HV primary windings

[Paul Decker]

I'm not sure that is exactly right.  I think what is being said is hanging the 120 VAC loads across half the primary.  In essence, the primary winding consists of two individual windings which can be placed in series to provide a 240 VAC primary, or in parallel to provide a 120 VAC primary at twice the current.  When configured in series as 240 VAC, the voltage at the center tap of the primary would be 120 VAC.  I don't see any safety issue with this configuration as the 120 load is not using the "ground" wire as a return path.  



What is the rub? 



Paul Decker (KG7HF) 


Message: 5 
Date: Sun, 30 May 2010 14:34:35 -0400 
From: Martin Flynn < maflynn @ theflynn .org > 
Subject: Re: [Amps] Bridging 120v loads across HV primary windings 
To: Vic K2VCO < vic @ rakefet .com >, AMPS List < amps at contesting.com > 
Message-ID: < 4C02AFBB.6050502@ theflynn .org > 
Content-Type: text/plain; charset =ISO-8859-1; format=flowed 

Vic, 
Run the 4 wire circuit and call it a day.    I ran this very issue by a 
licensed master electrician on Friday.   

Direct quote: "If any portion of the load is 120 volt, you need a 
neutral.  If you are hell-bent on a 2 wire + ground supply, get a 208 
volt fan and appropriately tapped transformer" 

Martin 
w2rwj