# Paralleling Three phase Delta

#### Mauiguy

Joined Apr 1, 2013
2
My question is: Is there a different way to parallel a three phase delta secondary connection besides 1. Connecting two of the phases together to get a reference point. 2. Doing the same thing but connecting the through a ground. I am looking for the best and safest way of doing this. Any ideas out there?

#### t_n_k

Joined Mar 6, 2009
5,447
The meaning of your question is uncertain.

Are you asking whether one can parallel connect two independent sets of delta connected 3-phase windings?

What do you mean by "reference point"? Do you want to create a virtual neutral for the proposed 3-phase connection?

#### Mauiguy

Joined Apr 1, 2013
2
I guess i am basically wondering when you parallel a 3-phase delta bank together with another 3-phase delta bank is it just as easy as using your Fluke meter across the phases to see if their is a voltage like you would for paralleling two single phase cans? Or is there a differenc being that it is three phase Delta?

#### t_n_k

Joined Mar 6, 2009
5,447
I'm reluctant to jump straight in with an answer as you have posted on the homework forum.

An implied condition in making the parallel connection would be that each transformer secondary has identical line voltages and operating frequency. Suppose that were true but you were unsure of the actual phase rotations applicable to each transformer. How to proceed with the proposed parallel connection?

As you have indicated - as a start one might directly connect/link just one terminal on each of the delta secondaries. To create a reference point as you remarked.

Then with your multimeter in hand and the transformers energised you would measure the AC potential differences between the other unconnected terminals - secondary to secondary. Provided you obtain two concurrent / independent cases of zero potential difference then you can confidently connect the relevant secondary terminals in those two cases.

#### JoeJester

Joined Apr 26, 2005
4,126
Let's see ... I've known some who "parallelled" three phase generators for various reasons. Like switching them to do maintenance on the one that was removed from the load.