Homebrew PCBs

Stefan Trethan: 

I don't know how often the members of this group will encounter the type of industrial transformers that 
you describe. But I do know that isolation (not insulation) is a factor to be considered,,,,,,,,,often when 
connecting your test equipment up to equipment that you might be troubleshooting, designing, etc. 

Refer to the conventional three-phase configuration that most of us encounter. 

Regards, 

Roland F. Harriston, P.D. 

----- Original Message -----

From: "Stefan Trethan stefan_trethan@gmx.at [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> 
To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com> 
Sent: Sunday, February 28, 2016 10:14:10 PM 
Subject: Re: [Homebrew_PCBs] Re: drill pcb 



Strictly speaking there are differences between an industrial control 
transformer and an isolation transformer. 
The isolation is often stronger with a dedicated isolation 
transformer, sometimes the windings are even physically separated in 
different chambers or on different shanks, instead of on top of each 
other. 
As a result coupling capacitance is lower with an isolation 
transformer, but also magnetic coupling is worse. 

So in some situations you may require an actual isolation transformer. 

Many high quality control transformers fulfill the minimum 
requirements for a safety isolation transformer, but always check the 
datasheet. 

ST 

On Thu, Feb 25, 2016 at 5:15 PM, Brad Thompson 
brad.thompson@... [Homebrew_PCBs] 
<Homebrew_PCBs@yahoogroups.com> wrote: 
> If you need to power a 120VAC item from a 240 VAC 
> line (or vice versa), you can use 
> a transformer **with isolated windings** designed exactly for this 
> purpose. These are sometimes referred to as 
> "industrial control transformers". 
> 
> 73-- 
> 
> Brad AA1IP 
> 
>