HUH???

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charlie

charlie

Senior Member
Location
Indianapolis
Re: HUH???

It is a three phase, three wire, corner grounded delta system or a three phase, three wire, corner grounded wye system where the the midpoint of one phase winding is not used as a circuit conductor and the center point can not be grounded in such a way as to be 150 volts or less to a phase conductor. :cool:
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: HUH???

Which one? The corner grounded delta is fairly common, esp. for small lift stations. An open delta can be used with a triplex service drop to a single phase type service panel using full voltage 240 volt two pole circuit breakers. Two phases and the grounded conductor makes a full three phase circuit to run three phase motors.

The corner grounded wye is rare but I hear it is used for some of the large pumps out west.
 
S

s wayne cook

Member
Location
Virginia
Re: HUH???

Charlie,
All the 3-phase services I've messed with are either 120/208, 120/240 high leg delta, or 277/480. All of these have three hots and a neutral, (grounded conductor). I've just never seen a 3-phase system that has only three conductors, one of which is a grounded conductor.
I must be confused. (And that doesn't take much for me).
Wayne
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: HUH???

Thar's ah bunch of'um out thar that ere differnt than them . . . HMMM . . . I just broke my spell checker again. LOL :D

Some services are ungrounded (240 volt delta, 480 volt delta, and 480 volt wye [if you don't take the neutral]). Some services are weird (Scott connected or 3 phase, 5 wire). And some services are corner grounded (see above answers).
 
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