High leg delta and corner grounded delta

[LarryFine]

So in a corner grounded system you can't pull 120v but since one of the phases is grounded it provides us with ground fault protection

Right. A common method of supplying 120v 1h loads is with a delta/wye transformer.

 

[electrofelon]

And how would you wire the corner grounded method in the field

Typically you would use a two-pole fused disconnect. The grounded phase would land on the "neutral terminal" in the disco. It would look very much like a single phase system would. One could also use a panel board with two buses and a grounded terminal bus.

 

[The electron man]

@LarryFine

You guys helped me understand it a bit better but I'm still not fully grasping it ,would

Mike holts book on grounding and bonding

Or
Soares book on grounding and bonding

​

Help me understand this better

Thanks again

 

[jim dungar]

@LarryFine

You guys helped me understand it a bit better but I'm still not fully grasping it ,would

Mike holts book on grounding and bonding

Or
Soares book on grounding and bonding

​

Help me understand this better

Thanks again

I used Soared during my career.
But I think this is an overall electrical theory issue, not simply grounding/bonding, so you should look into transformers/systems where Mike Holt would be a better choice.

 

[The electron man]

I used Soared during my career.
But I think this is an overall electrical theory issue, not simply grounding/bonding, so you should look into transformers/systems where Mike Holt would be a better choice.

I agree I'm lacking the electrical theory
I work for a merit shop so there is no schooling involved but I'm hungry to learn


So would mikes electrical theory course be a good start

Thanks for the reply

 

[electrofelon]

You guys helped me understand it a bit better but I'm still not fully grasping it

What aspect are you not understanding? The physical/construction part or the system grounding part? Or something else?

 

[The electron man]

A bit of both

I understanding how a basic wye and Delta transformer work and how the emf from the primary induces a voltage in the secondary

But having a hard time understanding how grounding Influence's the voltages and the effects it has on a system

Plus how its wired in real life in the field

I been doing this for 3 years but I feel like I'm missing something, on the daily I build out large electrical services and I'm the lead mechanic

 

[ActionDave]

But having a hard time understanding how grounding Influence's the voltages and the effects it has on a system

By grounding do you mean a connection to earth?

 

[Hv&Lv]

You could look on you tube also for open delta and corner grounded deltas

 

[The electron man]

By grounding do you mean a connection to earth?

Yes

 

[LarryFine]

But having a hard time understanding how grounding Influence's the voltages and the effects it has on a system

Plus how its wired in real life in the field

Read the part of my battery post (no pun intended) where I mentioned grounding one wire. The batteries deliver +1.5v and -1.5v to ground because the center tap is grounded. That's analogous to our 120/240v 1ph system. Two lines with 3.0v between them, and 1.5v to ground.

If the negative end was grounded instead (and the center tap ignored), there would only be +3.0v to ground available. That's analogous to the European 240v 1ph system (which is actually one line from a wye system.)

If you understand what determines line-to-line voltages, then you should get that the voltage to ground from each secondary line depends solely on which other line is (intentionally) grounded. A delta is ground-able in only two ways: One line or the center of one winding.

You may wonder why anyone would want a high-leg service. It may help to understand that the (open) delta began as a 3ph modification to existing 1ph services, where a single piece of 3ph equipment was needed. Thus, the center-tap neutral was pre-existing.

The 208v high-leg voltage is the result of the phase angles between one 240v side of the delta and half of the tapped-secondary's 240v with the 120 degrees thrown in. It's basically mathematics.

Try to give us a better idea of what you're having trouble grasping.