Generators and Electric Motors
[Home] - [HELP] - [Forums] - [Groups] - [Classified Ads] - [Subscribe] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion
Forgot Password? Join Us!

Notices

Generators & Electric Motors General Discussion Antique Generators and Old Electric Motors: Questions and answers about restoring and showing old power generation systems.

Generators & Electric Motors General Discussion

Three Phase Connection?


this thread has 21 replies and has been viewed 708 times

Reply
 
Thread Tools Display Modes
  #1  
Old 08-04-2019, 12:14:14 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Three Phase Connection?

Hey everyone, I've got a quick question,

Is it possible for a 9 lead machine with dual windings to have one set of windings in star and the other set in delta at the same time? These types of machines have the connections 10,11,12 joined internally with 9 leads in the connection box?
Seems from a quick look at some drawings, that such a connection is possible?

https://www.efficientplantmag.com/20...tion-mistakes/


Robert
Reply With Quote
Sponsored Links
  #2  
Old 08-04-2019, 12:39:50 PM
Wayne 440 Wayne 440 is offline
Registered-III
 
Join Date: Nov 2004
Location: Kentucky
Posts: 7,382
Thanks: 484
Thanked 6,875 Times in 3,193 Posts
Default Re: 3 phase connection?

It is certainly physically possible. That said, I have no idea what the effect on the machine would be.
Reply With Quote
  #3  
Old 08-04-2019, 01:58:56 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 6,004
Thanks: 9,861
Thanked 2,824 Times in 1,903 Posts
Default Re: 3 phase connection?

It would be possible, as long as you didn't then try to parallel the resulting two different voltages, and phase angles, of winding sets.

If this were a generator, you'd have two different voltages available, each capable of one half of the machine's total capacity.

If it were a motor, you could run it on one or the other voltage, but realistically at less than half power, since all of the magnetizing current would still be required... Unless you supplied somewhat lower than rated voltage...

What are you making?

Keith
Reply With Quote
  #4  
Old 08-04-2019, 04:12:14 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Quote:
Originally Posted by Vanman View Post
It would be possible, as long as you didn't then try to parallel the resulting two different voltages, and phase angles, of winding sets.

If this were a generator, you'd have two different voltages available, each capable of one half of the machine's total capacity.

If it were a motor, you could run it on one or the other voltage, but realistically at less than half power, since all of the magnetizing current would still be required... Unless you supplied somewhat lower than rated voltage...

What are you making?

Keith
Studying the seldom discussed induction generator connections after watching "Possum Living" do some load testing. https://www.youtube.com/watch?v=Q1GOr-S3BIs His motor is similar to mine and they both are 9 lead wye connected machines. His website shows how he achieved the C-2C connection. http://www.possumliving.com/2011/06/...ric-motor.html I cannot figure out how he got away with connection in delta to achieve the C-2C connection with a Wye connected 9 lead motor? I suspect he had the windings in star and the capacitors in half a delta connection, which I think would work but would be unbalanced. His scheme would work in C-2C if he had all 12 leads available and connected in High Series Delta. Then he would have L1-L2 240V and L1 to N 120v L2 to N 120V.

The correct connection scheme should be,

Cap 1, L1 to L2, Cap 2, L2 to L3, Cap 3, L3 to L1. Then there would be 120 volts from L1 to the star point, The same would repeat for L2 and L3 to the star point. L1-L2 should be about 208 volts.

There is a dozen connection schemes for these generators though. Even the standard connections for Onan's and Cat 3 phase generators can and do work on induction generators. Indeed, Marathon Electric has a PDF on the web for Prime Line induction generators with most of the standard connection schemes listed.

I guess the questions to answer is, How would the 9 lead wye connected motor favor with the accessible connections connected in delta with the excitation capacitors tying both sets of windings together? I think this is were I get confused actually?

Robert

Last edited by Railroads; 08-04-2019 at 05:40:03 PM.
Reply With Quote
  #5  
Old 08-04-2019, 06:34:57 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 6,004
Thanks: 9,861
Thanked 2,824 Times in 1,903 Posts
Default Re: 3 phase connection?

These capacitor excited induction generators (that technically correct?) are pretty well above my pay grade. I would just have to experiment and fool around with it while taking lots of readings to determine what may work best, or at least well.

Keith
Reply With Quote
  #6  
Old 08-04-2019, 07:32:51 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Quote:
Originally Posted by Vanman View Post
These capacitor excited induction generators (that technically correct?) are pretty well above my pay grade. I would just have to experiment and fool around with it while taking lots of readings to determine what may work best, or at least well.

Keith
Technically correct yes. That is what I am thinking too. I knew there was some experts on 3 phase generators around and was hoping for some insight and knowledge on what yields 1/3 vs 2/3 capacity of the winding sets?

Robert
Reply With Quote
  #7  
Old 08-04-2019, 08:01:49 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 6,004
Thanks: 9,861
Thanked 2,824 Times in 1,903 Posts
Default Re: 3 phase connection?

RadioMike is for sure our resident expert on these things. He really understands all that's going on in a three phase generator, under various conditions. There are probably others here too.

Keith
Reply With Quote
The Following User Says Thank You to Vanman For This Post:
  #8  
Old 08-04-2019, 08:11:41 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

I sent a PM.

Thanks.

Robert
Reply With Quote
  #9  
Old 08-05-2019, 07:14:50 PM
Radiomike Radiomike is offline
Registered-II
 
Join Date: Feb 2013
Location: Pincher Creek, Alberta, Canada
Posts: 501
Thanks: 0
Thanked 242 Times in 171 Posts
Default Re: 3 phase connection?

A nine lead motor / generator can be Y or Δ the nine leads enable you to have two voltage connections. The linking diagram to change between the two voltages will give you the answer whether it is a Y or Δ connection. Bringing out the star point can be done but if it is buried in the winding the risk is high. It is worth a careful look as the start point may be accessible. I did do it once to a 1HP but it was very tricky.

The classic connection is as you say C-2C. I did however find a paper in which a star winding is used.

https://www.researchgate.net/figure/...r_fig1_3270780

In this case the capacitors seem to be about the same values, motor run capacitors must be used, not the cheaper motor start type.

As regard to having one set of winding in Y and the set in Δ. The phase angle between them will be different and could lead to large circulating currents. There are designs for a Y winding with an Inner Δ. However you are seeking a Δ not a Y. It may be possible to use one set of windings, the outer star and reconnect these as a Δ, but it would only be part of the winding and reduce the voltage and power.

What is the name plate details of your motor?

Mike
Reply With Quote
The Following 2 Users Say Thank You to Radiomike For This Post:
  #10  
Old 08-05-2019, 09:30:20 PM
Jim McIntyre's Avatar
Jim McIntyre Jim McIntyre is offline
Subscriber
 
Join Date: Nov 2004
Location: Mooresville, Indiana, USA
Posts: 4,529
Thanks: 875
Thanked 2,697 Times in 1,542 Posts
Default Re: 3 phase connection?

Quote:
Originally Posted by Railroads View Post
...Studying the seldom discussed induction generator connections after watching "Possum Living" do some load testing...
I remember first learning about induction generators, and thinking it'd be a good way to build a general-purpose backup set. The more I learned about them, the less attractive they became. I've finally reached the conclusion (but I'm totally open to other's first-hand experience) that they might be a decent solution for a utility-tied co-generator (with proper protection of course). Other than that, they don't have much use for running the type of household loads I have. The optimum capacitor value varies with load. My loads vary a lot and I had no desire to control the cap values in real time based on the load.

I encourage you to tinker at them, but be open to the possibility that it won't yield any fruit...

(As an aside, the other thing I 'learned' that at first seemed super useful was the Scott T transformer connection. I mistakenly thought it could convert between single and 3-phase, but in reality in converts between two phase (quadrature) and three phase. Not having and two-phase power to start with, the Scott T connection is useless...)

---------- Post added at 09:30:20 PM ---------- Previous post was at 09:26:24 PM ----------

Quote:
Originally Posted by Radiomike View Post
...The classic connection is as you say C-2C. I did however find a paper in which a star winding is used.

https://www.researchgate.net/figure/...r_fig1_3270780
...


Easy-peasy - what could possibly go wrong?

Last edited by Jim McIntyre; 08-05-2019 at 11:22:05 PM.
Reply With Quote
The Following 2 Users Say Thank You to Jim McIntyre For This Post:
  #11  
Old 08-05-2019, 11:41:29 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Mike,

This is exactly what I want to know more about? Please tell me more.

Quote,

There are designs for a Y winding with an Inner Δ.

I also want to know about obtaining the C-2C connection with a winding set in Star connection? I think it's possible? But I need to see a good drawing to digest the connection scheme.

I have seen mention of using one of the 3 phases as the excitation winding. Usually this is done on the L3 phase and the power is taken from L1 and L2. I believe this is a horrible idea. But I want to know why?

The info packet on my motor is available here. https://www.baldorvip.com/servlet/pr...ket/M3615T.pdf

My motor is 9 lead star connected. I connect the caps in delta and obtain 120v phase to neutral across L1 to L3 to N for each phase. 230v across L1 and L2 or L2 and L3.

According to the two publications on induction generators, For a star connected motor you put the capacitors in delta. For a delta connected motor you put the capacitors in star. The drawback is star connected capacitors require twice the uf.

The two books are

"Manual-on-induction-motors-used-as-generators" This is volume 10 in Skat engineering's micro hydro series. http://skat.ch/book/manual-on-induct...ors-volume-10/

Out in the field some of what was theorized in the above book was found to be impractical in the field. Nigel Smith wrote "Motors as Generators For Micro Hydro Power" with the revised info gained from experiences in the field. http://www.fastonline.org/CD3WD_40/J...%20N.%20Smith,

Jim, The SEIG is actually quite useful for some applications.

The purpose of my research is to eventually get around to further investigating this fellow's idea of capacitor switching voltage regulation.

One must read the description very carefully to digest his circuit board design. https://www.youtube.com/watch?v=N3luyI2RIOc

I believe he is on the right track. But his diesel tractor is unsuitable for a induction generator. the engine doesn't respond quickly enough to load changes to hold the RPM constant. That is his biggest problem.

The current regulation scheme uses resistors or heating elements to load to full capacity the generator. When a load is added the controller switches out some of the resistance load.

Such a developed controller can be found here. http://www.microhydropower.net/mhp_g...humb_main.html This method works but is inefficient and puts a lot of strain on the motor/generator winding set.

My eventual goal in all this is to write a book on using induction generators and obtaining the split phase 120/240 of North America. I also want to dissect the various connection schemes and go over why some of them are poor choices without getting all technical if possible.

This paper drives me batty because the author uses a poor choice for connection of the windings. It will work, But doesn't make good use of the winding sets and available current. Argh! I want to re-write the dang paper using what knowledge I have gained and see if he would upload a revised version of his paper? http://www.redrok.com/cimtext.pdf

I'm on a crusade to replace the half baked, or just plain poor info available on the web regarding induction generators and 3 phase motor conversions.

Robert
Reply With Quote
The Following User Says Thank You to Railroads For This Post:
  #12  
Old 08-06-2019, 04:00:37 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Another area of interest is in using the magnetic amplifer to control the induction generator. Magnetic amplifiers being relatively simple and able to handle the high currents are well suitable for SEIG control schemes.

I wish this was more legible. https://apps.dtic.mil/dtic/tr/fulltext/u2/026393.pdf A very poor quality scan for sure.

Another document on the subject. https://pdfs.semanticscholar.org/7cf...1bb2c6f9e3.pdf

Some old books on mag amps, https://archive.org/search.php?query...+Amplifiers%22

A home made mag amp from Nuts & Volts. https://www.nutsvolts.com/magazine/a...etic_amplifier

Robert
Reply With Quote
  #13  
Old 08-06-2019, 08:04:55 PM
Radiomike Radiomike is offline
Registered-II
 
Join Date: Feb 2013
Location: Pincher Creek, Alberta, Canada
Posts: 501
Thanks: 0
Thanked 242 Times in 171 Posts
Default Re: 3 phase connection?

Magnetic amplifiers do look very simple, but to get one designed for your application will probably be more than having your motor rewound to delta. We used them at work for our automatic voltage regulators on sets up to 150MW designed in the early 1960's. These were transformer silicon steel cores and were in service for nearly 40 years.

There was reference to a circuit with three capacitors for a Y connected motor, this would seem to be what you needed. Although rewiring to Δ would be possible. Although this would leave you with a different voltage motor.

The capacitors are required to supply the reactive power needed for stand alone use for grid connected use the magnetising current will be drawn form the grid, making for a poor power factor.

The MPHG booklet contains a wealth of information. One of the schemes uses simple switched capacitors with voltage sensing relays, commendably simple.

Mike
Reply With Quote
  #14  
Old 08-06-2019, 10:03:26 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Repurposed grid tie solar inverter connected to a induction motor generator. https://www.youtube.com/watch?v=HUE1RQRAXlg

Robert
Reply With Quote
  #15  
Old 08-07-2019, 12:47:22 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Quote:
Originally Posted by Radiomike View Post
Magnetic amplifiers do look very simple, but to get one designed for your application will probably be more than having your motor rewound to delta. We used them at work for our automatic voltage regulators on sets up to 150MW designed in the early 1960's. These were transformer silicon steel cores and were in service for nearly 40 years.

There was reference to a circuit with three capacitors for a Y connected motor, this would seem to be what you needed. Although rewiring to Δ would be possible. Although this would leave you with a different voltage motor.

The capacitors are required to supply the reactive power needed for stand alone use for grid connected use the magnetising current will be drawn form the grid, making for a poor power factor.

The MPHG booklet contains a wealth of information. One of the schemes uses simple switched capacitors with voltage sensing relays, commendably simple.

Mike
Mike, I think we got a little confused. I know perfectly well the reasons for the capacitors. Been building these things for over a decade. The questions I have are in regard to how the caps tie the phases together to deliver the full potential or near to it out of the single phase connection.

The other part of the question surrounded how the inner wye connections, which are not accessible could be made to work with the outer winding being in the delta connection? Would it be possible to connect the motor up this way and not have magic smoke everywhere.

I appreciate the drawing you linked. I have been looking at it trying to decipher how to obtain the 120v in C-2C? I believe the output is infact 240v in the method you linked to for single phase? The star point would be the half voltage connection if the caps were in delta on a wye machine.

The drawing you linked is really nothing more than the caps being in the same Wye configuration as the winding set. But with one exception.

I have never seen the 2C drawn that way before at the bottom? I would think connecting the load between the two caps of the 2C would be problematic would it not? Certainly the 2C is less than the 1C though as caps in series cuts the uf instead of adding them.

Robert
Reply With Quote
  #16  
Old 08-07-2019, 01:22:01 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 6,004
Thanks: 9,861
Thanked 2,824 Times in 1,903 Posts
Lightbulb Re: 3 phase connection?

Interesting video. Sounds like the grid tie (synchronous) inverter is constantly searching for the maximum power point of the generator... Presumably the generator isn't stable enough, so the inverter is constantly hunting.

Keith
Reply With Quote
  #17  
Old 08-07-2019, 02:14:41 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

Quote:
Originally Posted by Vanman View Post
Interesting video. Sounds like the grid tie (synchronous) inverter is constantly searching for the maximum power point of the generator... Presumably the generator isn't stable enough, so the inverter is constantly hunting.

Keith
Keith, IDK? Possibly. Maybe he needed some serious filter capacitors on the DC output of the generator before the inverter? Personally, I don't think MPPT is quite what it's cracked up to be.

The guy did have quite a bit of trouble with the connection schemes. I found a discussion of his adventures with the induction generator. http://www.microcogen.info/index.php?topic=3180.0

Marathon Electric sells their Prime Line induction generators and have a schematic of the connection schemes here. http://hardydiesel.com/generator-end...generators.pdf They don't show any Delta connections though.

Robert
Reply With Quote
  #18  
Old 08-07-2019, 08:31:19 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: 3 phase connection?

I'm always inspired by Sparweb and his wind turbine builds. Using the link here for an example, http://www.sparweb.ca/3_Gen_MoCo/Baldy.html I don't think bringing out the ends of wires 10, 11, 12 would be all that hard. Then a proper delta and C-2C setup could be achieved. I did something similar once when I converted my Delco 27 SI alternator to Wye configuration to achieve 120v DC. Could only get 60 volts in Delta from the alternator.

Robert
Reply With Quote
  #19  
Old 08-07-2019, 10:08:28 PM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 6,004
Thanks: 9,861
Thanked 2,824 Times in 1,903 Posts
Default Re: Three Phase Connection?

I once put one of those silly auto power things on my van. It connects the field to the battery, and reconnects the armature from the 12 volt electrical system to a receptacle.

With the 440 wound up to around 4,000 rpm, it would make 120 volts. It would easily power a 1500 watt light bulb though. I wonder what was the efficiency of that?

Keith
Reply With Quote
The Following User Says Thank You to Vanman For This Post:
  #20  
Old 08-07-2019, 11:15:01 PM
Railroads Railroads is offline
Registered-III
 
Join Date: Sep 2013
Location: North Carolina, USA
Posts: 2,066
Thanks: 1,865
Thanked 1,846 Times in 810 Posts
Default Re: Three Phase Connection?

Quote:
Originally Posted by Vanman View Post
I once put one of those silly auto power things on my van. It connects the field to the battery, and reconnects the armature from the 12 volt electrical system to a receptacle.

With the 440 wound up to around 4,000 rpm, it would make 120 volts. It would easily power a 1500 watt light bulb though. I wonder what was the efficiency of that?

Keith
I collect those boxes. The one that eludes me is the Auto Pod V. I've got the GTO Pow'r Converter, Two of them in fact. Some of the early ones had screw in fuses. I passed one of them up. Shoulda snagged it. The Pod was unique as they had a semi automatic setup. Used some transistors and a vacuum selenoid as a crude throttle control.

Efficiency is crap. But they work for powering incandescent lights or a hand drill or power saw out in the field. I use one of the two I have for just such a setup.

Robert
Reply With Quote
The Following User Says Thank You to Railroads For This Post:
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Onan LTEU 30L 81H transfer switch converting from 3 phase 4wire to 1 phase 3 wire Mrfixit7777 Onan Generators 1 08-21-2018 09:54:50 AM
Bar Diamond or Collins Connection for 10 Lead 1 Phase 120/240 Birken Vogt Generators & Electric Motors General Discussion 7 12-15-2016 08:53:48 AM
Low ZigZag single phase connection grif Onan Generators 9 08-21-2013 11:21:27 PM
What is the 12 wire configuration for single phase connection? comsign Onan Generators 4 07-27-2010 05:14:42 PM
3 phase series wye connection Jim Rankin Generators & Electric Motors General Discussion 3 09-18-2006 08:36:28 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 01:40:17 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2019 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277