We will do 480 single phase for something light ballfield or racetrack lights where we wire all lights from one delivery point. Makes for some pretty long secondarys.
Delta and Wye Systems
- Thread starter Alwayslearningelec
- Start date
- Status
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Yep, you can be very creative when interconnecting single-phase transformer especially if they have taps which can be modified.
Alas, to many electricians are exposed only to factory built three-phase transformers using three sets of windings on a common core.
We have 3 (i believe) of these built along our system. Rural area, and they HAD to have 208.
It only works for light loads. Anything above about 50 kVa needs the third primary phase pulled in. Then it gets costly.
Interesting to note here, you can also get 120/240 single phase for your house from this configuration.
For more transformer info see Scott35's tech pages at EC-N
www.electrical-contractor.net
Technical Reference Area - ECN Electrical Forums
Electrical & Code Related Forum for Electricians, Inspectors, Instructors, Engineers & Related Professionals
www.electrical-contractor.net
AC\DC
Senior Member
- Location
- Florence,Oregon,Lane
- Occupation
- EC
Do you have a link to that page I like the layout.
Sorry, no link. There may be one somewhere, i don't know.
its a picture I've had for years on my computer.
Aaron@aaroncarterelectric
New User
- Location
- Houston
- Occupation
- Electrician
Hi
We came across a delta service from provider. A=120 to N B=120 to N C=213 to N Customer is wanting to add some equipment that requires 460 volts three phase. Everything in the shop is listed 240 volts 3 phase. It is a mess. What are our options?
We came across a delta service from provider. A=120 to N B=120 to N C=213 to N Customer is wanting to add some equipment that requires 460 volts three phase. Everything in the shop is listed 240 volts 3 phase. It is a mess. What are our options?
Step up transformer. You should probably start a new thread.
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
And search the forums for "high leg delta" and "240/120 three phase".
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
as mentioned step up transformer, but make sure to use one that is 240/480 and not 208/480.
Other options are to add additional 480 service or even switch service to 480 and separately derive and supply the 240 from the new service.
If the new equipment is significant enough load you might be doing some upgrading to service anyway.
Also depending on that equipment if it is dual volt capable you could configure it for 240 volts.
electromagnuts
Member
- Location
- USA
- Occupation
- EE
I am beating my head against this one (probably for no reason): What if you connect a Delta transformer to a Wye source? Say you have a medium voltage multi-grounded wye distribution system and someone decides to connect a delta txfr up to the three phases. P2P voltage will be the same but would it create some crazy circulating current? Similar to this with the wye neutral grounded.
bitdrivencircuits.com
Balanced Y-Delta Connections
In this section we explore three-phase Wye-Delta systems.
bitdrivencircuits.com
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Transformers with delta primaries are regularly connected to Wye sources, such as a typical 480V primary with a 208Y/120V secondary.I am beating my head against this one (probably for no reason): What if you connect a Delta transformer to a Wye source? Say you have a medium voltage multi-grounded wye distribution system and someone decides to connect a delta txfr up to the three phases. P2P voltage will be the same but would it create some crazy circulating current? Similar to this with the wye neutral grounded.
Balanced Y-Delta Connections
In this section we explore three-phase Wye-Delta systems.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
230208-2254 EST
If you have three wires going to a location, either fed from 2 phases of a 3 phase source, or 3 phases of a 3 phase source, you can have 3 phase wye or delta at the load end if desired.
.
If you have three wires going to a location, either fed from 2 phases of a 3 phase source, or 3 phases of a 3 phase source, you can have 3 phase wye or delta at the load end if desired.
.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Utilities will almost always use a wye primary on an MGN distribution system. If I remember correctly the reasons are they are a little bit cheaper and less likely to suffer ferroresonance. That said, I'm sure a Delta would be fine. Of course for low voltage, Delta primaries are fed off of wye systems all of the time.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I don't get the + and - indications in that wye side at all. Sure you could show such polarity for an instant in time, but in such arrangement those are 120 degrees apart at any given moment in time, here they are all shown as having the neutral side being negative which would never happen simultaneously.I am beating my head against this one (probably for no reason): What if you connect a Delta transformer to a Wye source? Say you have a medium voltage multi-grounded wye distribution system and someone decides to connect a delta txfr up to the three phases. P2P voltage will be the same but would it create some crazy circulating current? Similar to this with the wye neutral grounded.
Balanced Y-Delta Connections
In this section we explore three-phase Wye-Delta systems.
They also kind of indicating direct current flow, reality is at the wye point as well as each corner of the delta there is currents flowing in three different directions at all times.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Transformer polarity has a certain specific meaning and is important in some situations:
Transformer Polarity
Transformer polarity is fundamental to grasping how transformers function and how they’re utilized.
energycentral.com
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Text books regularly show all power sources, both AC and DC with some type of polarity marking. They also usually consider AC values as being 'frozen' in time based on those markings.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
Ok, but clearly the illustration is about transformer polarity which has a specific meaning, it has nothing to do with polarity in the common sense of the word.
electromagnuts
Member
- Location
- USA
- Occupation
- EE
Thanks for the insight! I guess I am surprised by this and my gut is telling me this is a bad idea but I am having trouble coming up with any legitimate reasons. The first thing I think of is losses. The conductors themselves between the substation wye txfr and the distribution delta acting as a resistive load and enabling a circulating current. Maybe an inherent impedance mismatch between the transformers? I mean, transformers that convert from wye to delta exist all over just fine but they also have a core that acts as the interface. But here the interface is distribution lines, which I suppose in this case, is forced to act like a core?
The other thing is... why? Why connect a delta txfr to a 4-wire wye distribution system only to convert it to wye again on the secondary side? Just to avoid having to run a neutral? Work practice/safety?
I haven't even begun to think about the implications of taking a single phase lateral off this setup. But again, I'm an idiot and I am probably just creating some high school drama in my own head. I mean, these systems have been in operation for ages.
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