Wye 3 phase to single phase distribution woes

In summary, the individual is planning to use a 125amp, 240v three phase circuit to power a 30 kva UPS through a delta/wye transformer, with 208/120v three phase entering the panelboard. They plan to use 50 amp, 3 pole breakers with a neutral and ground to create 5 wire three phase. The individual is wondering if it is possible to bring the 5 wire, three phase out to the field and create three single phase, 120vac circuits. They are looking for feedback or alternative solutions. It is recommended to use single phase circuit breakers in the panelboard to supply the equipment. The equipment runs 24/7 with different loads, so it is
  • #1
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I have a 125amp, 240v three phase circuit feeding a 30 kva UPS through a delta/wye transformer, leaving 208/120v three phase entering my panelboard. I plan to use 50 amp, 3 pole breakers, with a neutral and ground, making 5 wire three phase.

My question is: When I bring the 5 wire, three phase out to the field, I want to make three, single phase, 120vac circuits. Can anyone provide feedback, parts that could make this happen, or tell me I am nuts and then offer another solution?

Thanks
 
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  • #2
You won't bring the three phase out into the field, you will have single phase circuit breakers in your panel board that supply single phase (Active, Neutral and Earth) supplies to the equipment. The active is one of the phases that has been brought into the board. Each circuit can be on a different phase.
 
  • #3
Im bringing the three phase because the runs are over 1000 feet. I am going to run awg 4 stranded copper wire to reduce voltage drop.

Is there a panelboard that will accept a 3 wire three phase main, provide a nuetral and ground bar, and have single phase breaker outputs that will ensure balanced loading throught the phases?

A model number would be appreciated if this exists, or i may just be retarded
 
  • #4
I can't help with a model number, I live in Australia, but what you have described is what happens most of the time in panel boards, 3 phase in/single phase out. If you are supplying 3 pieces of equipment then its easy to put each one on a different phase. As for balanced loads, it depends on when the equipment runs.
 
  • #5
the equipment runs 24/7 but it has different loading at different times.

btw, is your name a jay and silent bob quote?
 
  • #6
Yes it is, I have been using it for a very long time.

There isn't much that can be done about balance at the design phase other than trying to spread the loads as equally as possible. If it is going to be a problem, the use of 3 phase equipment should be considered (if possible).
 
  • #7
the 120v feeds from the 3 phase sub panel are going to equal transformers, perhaps a 1kva 120v/24v transmformer. These are all identical.

Would it be better to run a different UPS? Possibly a 240v 2-phase (L,L,N,G, if that's even right) circuit to the distribution for 120v circuits?

I ultimately need 120v at the field locations, which are far from the UPS. What do you think?
 
  • #8
Chances are the loads if only 1kVA aren't going to be much of an issue for balance. There is always inbalance.
 
  • #9
Thanks, appreciate the advicer
 
  • #10
Yes, they make 208Y/120V panelboards. There are 3 line lugs (one for each leg of the 3 phase). There is also a neutral bus bar and a ground bus bar which should not be bonded together since, in your case, this will be a sub panel (this should only be done at the main panel).

They are quite common. All the major companies dealing with electrical distribution carry them (G.E., Square D, Eaton, Siemens, etc.)
 

1. What is a Wye 3 phase to single phase distribution?

A Wye 3 phase to single phase distribution is a type of electrical distribution system that converts three-phase power into single-phase power. It is commonly used in industrial and commercial settings to power single-phase equipment.

2. What are the common issues or problems with Wye 3 phase to single phase distribution?

The most common issue with Wye 3 phase to single phase distribution is an imbalance in the load across the phases. This can lead to overheating and damage to equipment. Other issues include phase voltage fluctuations and power factor imbalances.

3. How can an imbalance in load be prevented in Wye 3 phase to single phase distribution?

An imbalance in load can be prevented by properly sizing and balancing the phases. This can be done by evenly distributing the single-phase loads across the three phases and ensuring that the total load on each phase does not exceed its capacity.

4. What are the solutions for voltage fluctuations in Wye 3 phase to single phase distribution?

There are several solutions for voltage fluctuations in Wye 3 phase to single phase distribution. These include using voltage regulators, installing power factor correction equipment, and implementing a balanced load distribution.

5. How can power factor imbalances be corrected in Wye 3 phase to single phase distribution?

To correct power factor imbalances, power factor correction equipment can be installed. This equipment helps to equalize the reactive power demand on each phase, resulting in a more balanced power factor and improved efficiency of the distribution system.

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