The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
Yesterday at 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 15
HotLine1 10
Trumpy 8
Texas_Ranger 8
sparkyinak 7
Who's Online
1 registered (gfretwell), 225 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#127212 - 05/11/01 12:28 AM 9 phase schematic - 5th in the series
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA


This schematic is for the 9 phase rectifier transformer, shown on recently posted picture.

This one has 1 delta 3 wire secondary [X1, X2, X3], plus two Wye 3 wire secondaries [Y1, Y2, Y3 and Z1, Z2, Z3].

Comments??

Scott SET - can't spell at all
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top
#127213 - 05/11/01 04:48 AM Re: 9 phase schematic - 5th in the series
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
would'nt the 'umph' be somewhat split up in the secondaries?


Top
#127214 - 05/11/01 10:23 AM Re: 9 phase schematic - 5th in the series
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
Ya, the total Umph would be very much split up in the secondaries, so having a good balance of load on each secondary is really something to drive for.

Since this Animal is intended to drive Rectifiers, I imagine the loads across each secondary would be closely matched.

The output of the complete Rectifier using all these secondaries would have minimal "ripple Voltage" [the resulting left over peaks of the AC waves imposed on the DC flows]. The ripple is lessened due to an increase of 6 more waves per rotation cycle, than straight 3 phase [rotation cycle meaning for 3 phase there are 3 separate cycles with peaks at + and - per one rotation of the generating device - if that makes any sense ]
I'm not sure of how to explain that, as I have just come up with that term "rotation cycle". Persons should not try to look it up in tech books for verification, as it only exists in tech books from the planet Dingleberrious 9 [my home planet].

Looking at this as compared to various 1 phase rectifiers, the quality of output DC is far better - even across a 3 phase bridge [as compared to a full wave bridge 1 phase rectifier].

This transformer's ratings are:
E-pri: 480 VAC 3 phase [+/-10% of primary taps] Primary taps allow from 432 to 504 volts to be used.

E-sec: 120 VAC [all 3 secondaries have 120 VAC output*]
Max total KVA: 200 KVA
Z= 5.0% [+/- 10%]

* I need to verify these voltage listings, as they were N/A at the time of photographing

Scott SET
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top
#127215 - 05/12/01 06:50 AM Re: 9 phase schematic - 5th in the series
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
OK,
so why would one of these, or where would one be used ?

(God, i sound like bugs bunny after a hit to the gourd ....what..who...where..why...how....)


Top
#127216 - 05/12/01 07:08 AM Re: 9 phase schematic - 5th in the series
sparky66wv Offline
Member

Registered: 11/17/00
Posts: 2339
Loc: West Virginia
Ski Lifts and other DC safety equipment requiring foolproof operation?

I think I've seen these at a local ski resort...

Dspark has a point in the other thread...
How are these other "phases" derived?
How does it differ from a 120/240V single phase coil split?
Could a cap be used to lag the sine wave?

More Q's than A's for me!

[This message has been edited by sparky66wv (edited 05-14-2001).]
_________________________
-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Top
#127217 - 05/19/01 03:30 PM Re: 9 phase schematic - 5th in the series
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
This schematic has also been [or bean if we're talking chili ...] edited in AutoCAD, then reposted.

It's a whole lot bigger now than before, so no need to use microscope

Scott SET
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top
#127218 - 05/20/01 11:20 AM Re: 9 phase schematic - 5th in the series
Phil H Offline
Member

Registered: 04/14/01
Posts: 24
Loc: Tujunga, CA
Scott,

Thanks for all of the transformer theory, I knew practically nothing before you began these series. I had a couple of questions that I think I know the answer to, but just wanted to ask to make sure.

On the primary of this transformer, each phase has two coils in series. Does each coil on any of the secondaries derive power from both coils in series on the primary? Or, does a coil on any of the secondaries derive power from only one coil?

The primary coils have what appears to be taps numbered 5 3 1 2 4 6 with a jumper between 3 and 2. Are those taps used to trim the input/output voltage ratio? Or do they have something to do with the lead and lag of phases you mentioned earlier?

While on the subject of lead and lag (which makes my brain hurt). Is this accomplished somehow by the way the wires are wound and positioned or are there other components in the system which are used? I really don't think I am ready for complex theory if it is accomplished in the windings, just curious?

Thanks again.
Phil H

Top
#127219 - 05/20/01 11:38 PM Re: 9 phase schematic - 5th in the series
Scott35 Offline

Broom Pusher and
Member

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
Phil,

Glad these discussions are helping out!!! That's what they are all about.

To your Qs:

1: These coils for the Primary Windings are connected in Parallel with each other [3 seperate single phase 2 wire coils], forming the common "Closed Delta" connection.
If they were connected in series, then it would be a Wye connected Primary.
However, there is an alteration to what I just said here, which is related to your 2nd question.

2: Yes, the 1,3,5 - 2,4,6 taps are as you thought, voltage regulation taps for input Primary voltage [% voltage taps].
In a way, this has created split coils on each primary winding, and the tap points will be connected in series.
We do have two coils per primary phase here, as would be the typical split coil transformer. In addition to these split coils, we have Autotransformer sections at the ends of the coils. The % voltage taps accomplish voltage regulation [more like voltage matching] through the use of the Autotransformers' multi tap points. Connecting the series jumper between the split coils on a certain set of taps will adjust the overall voltage for that winding. This should match closely to the normal voltage in which the primary will be dealing with on-site.

3: Right again!! Coil winding vs core flux [relative polarity] is the key here.
Kind of hard to explain, even harder to type it out, so let me see what I can do about translating this into something understandable.

Great Qs here!!


Scott SET
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals