>>"I would have assumed that a manufacturer would mark the polarity somehow on the case. I guess not?"<<
[Zargon]
>>>>>>>>
It is important that the user follow the wiring configuration diagram when hooking up the xfmr. Usually the winding leads are marked in some fashion. Most commercially sold transformers sold for power applications are marked with letters and numbers.
Example,
H = high voltage, primary side of the transformer.
X = low voltage, secondary side of the transformer.
Numbers on leads,
if the xfrm only has one primary winding the the leads may be identified by H1 and H2. If the primary has two winding the leads will be identified by H1 and H2 first winding, and H3 and H4 the second winding.
For the secondary of an isolation transformer most power application transformers have two secondary windings. Winding one leads are identified X1 and X2. The second winding X3 and X4.
If the manufactured labeled the windings correctly, and the big boys do, then the correct polarity of the primary to secondary winding should be,
H2 > X2
H4 > X4
==========
>>"Also, I am interested in whether you are leaving the secondary floating (no connection between common and ground on the output side) when connected to your CDP? I believe that is the recommended approach in order to maximize noise isolation."<<
>>>>>>>>>>>>
No, per NEC the center point must be bonded to earth ground. When using an isolation transformer for power application you are creating "A separately derived AC system." In simple terms you are creating a new electrical service, basically like the one feeding your home. NEC requires all AC power systems shall be AC grounded systems.
So if the secondary is 60/120V or as many call it
60V-0V-60V the center tap of the two windings shall be bonded, connected, to earth ground. What this means is the center tap shall be connected to the grounding electrode system of the main electrical panel system of your home. You can run a separate ground wire all the way back to your main incoming metallic domestic water line and install an aproved water pipe ground clamp there if you want.
Why does NEC require the secondary to be grounded? Safety, in the event of a leak or ground fault from one of the two hot conductors the fault current will travel back to the source, the isolation transformer. If the fault current is large enough it will cause the secondary over current device to open. If there is not overcurrent protection on the secondary the transformer will overload and cause the overcurrent device of the circuit feeding the transformer to open, a breaker in your main panel.
=======
Phase relationship
http://www.ibiblio.org/obp/electricCircuits/AC/AC_9.html
>>"Finally, can you report to us in more detail the differences in sound now that you can listen both with and without the ISO?"<<
I will try to report back this week
[Zargon]
>>>>>>>>
It is important that the user follow the wiring configuration diagram when hooking up the xfmr. Usually the winding leads are marked in some fashion. Most commercially sold transformers sold for power applications are marked with letters and numbers.
Example,
H = high voltage, primary side of the transformer.
X = low voltage, secondary side of the transformer.
Numbers on leads,
if the xfrm only has one primary winding the the leads may be identified by H1 and H2. If the primary has two winding the leads will be identified by H1 and H2 first winding, and H3 and H4 the second winding.
For the secondary of an isolation transformer most power application transformers have two secondary windings. Winding one leads are identified X1 and X2. The second winding X3 and X4.
If the manufactured labeled the windings correctly, and the big boys do, then the correct polarity of the primary to secondary winding should be,
H2 > X2
H4 > X4
==========
>>"Also, I am interested in whether you are leaving the secondary floating (no connection between common and ground on the output side) when connected to your CDP? I believe that is the recommended approach in order to maximize noise isolation."<<
>>>>>>>>>>>>
No, per NEC the center point must be bonded to earth ground. When using an isolation transformer for power application you are creating "A separately derived AC system." In simple terms you are creating a new electrical service, basically like the one feeding your home. NEC requires all AC power systems shall be AC grounded systems.
So if the secondary is 60/120V or as many call it
60V-0V-60V the center tap of the two windings shall be bonded, connected, to earth ground. What this means is the center tap shall be connected to the grounding electrode system of the main electrical panel system of your home. You can run a separate ground wire all the way back to your main incoming metallic domestic water line and install an aproved water pipe ground clamp there if you want.
Why does NEC require the secondary to be grounded? Safety, in the event of a leak or ground fault from one of the two hot conductors the fault current will travel back to the source, the isolation transformer. If the fault current is large enough it will cause the secondary over current device to open. If there is not overcurrent protection on the secondary the transformer will overload and cause the overcurrent device of the circuit feeding the transformer to open, a breaker in your main panel.
=======
Phase relationship
http://www.ibiblio.org/obp/electricCircuits/AC/AC_9.html
>>"Finally, can you report to us in more detail the differences in sound now that you can listen both with and without the ISO?"<<
I will try to report back this week