JD is likely referring to this post, containing amp meter readings. Note that the dimmers powered only 120V incandescent loads. The 208V distros are for the moving lights.
Some clarification might be in order here. I'm seeing what strikes me as some confusion when we're talking about delta- and wye-connected systems here. When I here of a 208V, 3 phase system, I assume that the source is wye-connected, as that is easily the most common configuration that produces 208V. In this wye-connected system, each phase is 120V with respect to neutral, and 208V with respect to the other phases. I've not run across a 208V delta-connected source. If you did run across such a source, you would only have 208V available, no 120V.
A 208Y, 3 phase, wye-connected system, denoted as 208Y/120V, can have delta- and wye-connected loads. A 208Y, 3 phase, delta-connected system can only support delta-connected loads. The distinction between how the source is connected and how the loads are connected is an important one.
If I've made any mistakes, someone please correct me.
Almost correct--one can make a delta connection to a 208Y/120 source in two ways:
A. Connect 3-phase loads that use no neutral, such as motors.
B. Connect multiple single-phase 208V loads between phases, with no neutral connection. This is typical for large moving lights in North America.
It would be rare to find a 208V delta source with no neutral. More likely, a delta source would be 240V or 480V in North America. To complicate matters, that 240V delta source might be a high-leg delta with the neutreal as a center-tap of one of the phases, in order to provide a small amount of 120V in a facility that uses mostly motor loads, such as a factory.
ST
I've more commonly seen the 240V high-leg delta used to provide a small amount of 3 phase power to a facility that has mostly 120V loads. The center-tapped transformer is generally the larger of the 3, say a 100kVA center-tapped 240/120V transformer and (2) 50kVA 240V transformers. This is a common commercial and industrial setup that I've ran across multiple times. Though I can't say I like it too much. It makes it difficult to upgrade the 120V portion or the service. I've got a substation project in Utah that I'm working through this problem on right now.
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