Electrical theory question...
Let's take as an example 50AMP RV service. A voltmeter between the two hots shows 240 volts, between one leg (or the other) and neutral shows 120 volts. My question concerns what happens when each...
Forum Discussion
MEXICOWANDERER wrote:
Good graphics RoyB!
MyRedRacer
A WYE connected 3-phase service drop transformer with different L0 to Lphase potential? I don't thing so...
A DELTA transformer with mid-phase neutral tap is the norm in the USA. Down here four wire high voltage 3-phase transformers are the norm. Wye connected transformers.
Delta transformers with 120 volt service on two phases offer 277 and 208 volt service.
Actually, the three phase 208Y/120v drawing shown by Mr. Red is very common in the states. This is typical for a light industrial installation where there are nominal three phase loads such as mills and lathes. The 208 3Ph power is adequate for the loads, and the phase to neutral of 120v is adequate for typical single phase loads such as convenience outlets and lighting. We frequently take 3ph, 480 vac service and drop it down via transformers for customer use.
On the other hand, 3ph, 240vac services are quite rare here because it then typically requires another transformer to get the 120v 1ph. Seldom do we see a high leg from a 240vac transformer being used for that service.
