Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Tool Talk Discussion Forum

3 P Converters on compressors dont Re:Phase conver

[Show Entire Topic]  

Welcome Guest, Log in or Register
Author 
benny2

03-06-2006 12:22:35




Report to Moderator

3 phase Converters on compressors dont work well if at all. Mostley wont start the motor at all. I think you will also find is the case and will have to change the motor to a single phase motor. I have built many phase converters and have installed some factory machines. None ever preformed. But on most any machine that has a no-load start they work well. If you do get it to start it will most likly be, if wired for 440 V 3P. using a syep up transformer. With a run motor of at least 3 to 5 times larger than the motor being run. Compressors will just blow the static units up. The wild leg is the generated leg when using 220 split phase for a power source. And it can vary wildly from site to site. Both high and low. That is why I always use a balance transformer with a multi voltage step unit to balance the voltage.

[Log in to Reply]   [No Email]
scott#2

03-07-2006 18:16:23




Report to Moderator
 Re: 3 P Converters on compressors dont Re:Phase co in reply to benny2, 03-06-2006 12:22:35  
This rotary converter is a 20 hp unit (de-rated by baldor from a 25 hp unit for 50hz canadian) and it turns this pump just fine and with no strain. It also starts and runs a 10 hp motor on a 20" leblond lathe set at the highest spindle speed. I suppose if you were trying to run a 15 horse air pump, without an unloader, it would porbably make a fuss though. So far, so good.

Thanks Benny

scott

[Log in to Reply]  [No Email]
benny2

03-08-2006 09:53:42




Report to Moderator
 Re: 3 P Converters on compressors dont Re:Phase co in reply to scott#2, 03-07-2006 18:16:23  
First if you have 50 htz you are losing motor RPM, and most all standard motors will run on any cycle just changes the RPM. Little torque loss. If your converter is working well on the compressor great, but you may have a commercial built unit with a bank of smoothing capcitors, if you have these, the continus use of high starting loads will damage them. The other thing that helps you may actualy have a full 2 phase power. You can idenify this by looking at your overhead supply (power pole) if there are 3 wires you may be hooked to 2 p power. If you have only 2 over head wires you have 1 p power, not the best. I have seen where 2 p power is used things just work better.

[Log in to Reply]  [No Email]
scott#2

03-09-2006 17:55:59




Report to Moderator
 Re: 3 P Converters on compressors dont Re:Phase co in reply to benny2, 03-08-2006 09:53:42  
Benny,

Not to beat a decaying horse to sub terranian depths but this converter rus on 220 single phase, I have never had any other power available. The 50 hz thing is nameplate only, there isnt any difference in the internals of the motor. The Baldor engineer said that they (when I read the spec# to them) will take a standard motor of higher hp and derate the motors spec plate only so it can handle the strain of being run reliably on less power and still provide the hp the customer is looking for. This particular motor cost me 65$ and runs at, if I remember correctly at 3450 rpm. Most converters I have ever built run at 1750 rpm. You get a much more powerful converter with the higher rpm motors but you have to have the electronics behind it to back it up too. REAL caps and lots of them for heat disipation, proper balancing, (2-3% under load), etc,etc,etc. This converter is much better than you can buy but I still consider it to be a hi dollar one because I have about $270 in it. I am an electronics technician by trade but am still learning about this high voltage stuff. If you want, start a new thread, I am always looking to learn about electricity and its fundamentals.

scott#2

[Log in to Reply]  [No Email]
benny2

03-10-2006 11:00:48




Report to Moderator
 Motor rated RPMs make little Re:Phase converters in reply to scott#2, 03-09-2006 17:55:59  
I know that the 50 Hz tag thing is just that a tag, no motor difference.
The speed factor of one motor rated speed suitability over another is a common misconception. Other than that of a manufacturing quark of the low speed motors of equal power, they just have to be larger rotors to accommodate the space for more stator windings, which in fact would prove to be a better power provider and esier starter. The power generated by any speed of motor will be the same as any other speed of motor if the rotor (armature) mass is the same. It is simple to say that motors with more rotor mass for the same HP rating, will be better phase generators. The rated speed of the motor has little or no effect on the production of power. 3450 rpm motors power is no better than that of a 12 pole motor. The 2 pole motor may in fact be a poorer choice as the rotor mass may be smaller and it takes more input power to maintain the RPMs with small fluctuations making a big difference in output.
You can view it as this as, there are 12 steps to the courthouse door, you can take each step one at a time or you can make it in 2 steps 6 at a time. Considering the extra amount of energy it takes to make the 6 step jump is it worth it, as the end result is the same. So if you needed to climb these steps all day long every day you would be able to climb longer and with less effort taking fewer steps each time. The difference in the synchronous and the actual run speed is what generates the power. If the motor running speed was exactly the same as the synch speed there would be no generation at all. Running speeds over the synch speed will cause the voltage to increase, speeds below the synch speed will cause the voltages to drop. That is where the balance caps come into play, to level this voltage off. I use pony motors to start the system as a less expensive alternative to starting with caps. In the long run the pony motor system also will be an easier and more reliable system to maintain.

These are the "Synchronous" Speeds for 3 phase motors (rpm) actual running speeds will be slightly less as noted by the motor tags.
Pole number
== 50 Hz 60 Hz
2 = 3000 3600

4= 1500 1800

6= 1000 1200

8= 750 900

10= 600 720

12= 500 600

[Log in to Reply]  [No Email]
scott#2

03-10-2006 14:03:30




Report to Moderator
 Re: Motor rated RPMs make little Re:Phase converte in reply to benny2, 03-10-2006 11:00:48  
Well I guess you told me. I had to read that thing 3 times before I beagan to catch half of it and on the 4th time, my eyes began to glaze over. Its quite obvious that Im not as smart as you when it comes to building these things, I usually go by trial and error and a few zaps along the way. (keeps me on my toes)

I am assuming by your post that the motor I am using is not as good as it could be? The higher the # of poles the better??? If phase converters are lousy at running air compressors, why does this one work so well and especially at turning that big 10 horse leblond? Im really confused now. Did I just get lucky or something? Is it possible that this motor has a higher pole count than other 3450 motors?

Thanks Benny,


scott#2

[Log in to Reply]  [No Email]
benny2

03-10-2006 19:34:49




Report to Moderator
 Two pole motors are actually Re:Phase converte in reply to scott#2, 03-10-2006 14:03:30  
Two pole motors are actually 3 pole motors one extra pole is offset said to cause what is known as a heavy north. With 2 pole motors they may start very hard on a dead center lock without it. All 60 Hz motors that are rated at 3450 or so, the RPMs varies slightly from make to make, are considered 2 pole. So if your motor is 3450 it has or is considered to have 2 poles. The flux tear or generator slip as it known, is only the difference of the actual run speed and the natural ("Synchronous") speed of 3600 which is only 150 rpm. When this speed fluctuates the power output fluctuates and causes cycling.
Now you just happen to have what I consider the best motor, the Baldor, for use in phase converters. To make your system run at optimum performance, there are a few things that will make this a great system. The first thing is to make sure is that the "generator motor" is running in the same direction as the air compressor motor. That the leads meaning the 1 2 3 are in parallel to each other in their respective connections. Now I am not any smarter than most any average guy I just took an interest in these units as I did accumulate many motors that I needed to find a market for. I have been at these things "converters" for nearly 35 years. And was very curious in more than just putting them together I wanted to know how they worked. There are no books out there on the theory at least not when I started with them. But I got very lucky on having a teacher about Induction generators. He may have been the originator to the whole home brew 3 phase power thing. His first one he built was in about 1951. He was an electrical engineer that worked for BPA that was on loan to the Bureau of Reclamation that was on a quest to develop inexpensive micro generating plants for farms and rural areas using the water power that fed the farms in the Columbia Basin Wa & Or. When looking into this they developed mini Hydro Plants on the farms using induction motors as generators (mostly 12 pole). Most wind towers now use this same plan and concept developed then. This was mainly before the Power was installed in much of this area. While not much came of this then, as it was scraped in 55 or so, what he learned there was put to use in the phase converters. At first he just showed me how to make them, but I wanted to know how they worked. Well the rest is just history. You now know the most basic of what I know about them. There is more tech stuff that dont really help much. But if you know the basics you can figure out systems on your own. This info is meant to be shared and not to show how clever I am. I am sure you are aware of the dangers of high value caps so not much to be said here except that one got me once and blew a large chunk out of the end of my thumb.

PS I t doesnt seem to matter how much we know about these things sometimes we get lucky with them and sometimes we dont, that the way it is with unengineered surplus parts ;((

[Log in to Reply]  [No Email]
scott#2

03-11-2006 10:30:53




Report to Moderator
 Re: Two pole motors are actually Re:Phase converte in reply to benny2, 03-10-2006 19:34:49  
Very interesting Benny, you've had quite a run at these things, I am still learning. I grew up in an electronics whirlwind. Dad was a ham since he was 12, needless to say we had our share of projects over the years. I was building tv's, tube testers, transmitters, receivers, radios, qrp rigs, you name it when I was 8. Dad used to give me small caps to play with back then and I would charge them up, take them to school and let my classmates play with them. Got thrown out of school a few times for that. I remember one day he gave me a schematic and told me to go get the parts out of the junk drawer and rob some old chassis pieces. I put the thing together and hooked a 6v battery to it and a meter long piece of wire for an antenna and he worked a guy in so. africa, morse code. I think I was about 6 then and I was hooked, totaly astounded me. He was quite a guy. Bomber sqardran commander, test pilot, saturn 5 project team leader. I sat on Dr. Werner Von Brauns knee as a kid after he defected from Germany. Knew all the astronauts, even the 3 that burned in Apollo 11. Its tough to live up to or even try to compete with the fine people of thet era, they just dont make them like that anymore. Ive always been a jack and never a master as dad was. Thank God for these forums and the Highly Intelligent and Compentent People that come visit, at times I would be lost without them.

Thanks for the info Benny, Ive printed it out and put in in the converter info file for future reference, I never knew all that about motors.

scott#2

[Log in to Reply]  [No Email]
buickanddeere

03-07-2006 19:21:58




Report to Moderator
 Canada 50 Hz ??????????????????????????????????? in reply to scott#2, 03-07-2006 18:16:23  
Everthing in Canada is 99.999% 60 cycle. Three phase is 120/208 or 347/600. There is a very small amount of 240/416 in downtown Toronto but it's rare and weird.



[Log in to Reply]  [No Email]
scott#2

03-08-2006 03:35:28




Report to Moderator
 Re: Canada 50 Hz ????????????????????????????????? in reply to buickanddeere, 03-07-2006 19:21:58  
Thats what it says on the name spec plate and thats what baldor told me. Maybe I got the wrong country but I believe he said Ca.

scott



[Log in to Reply]  [No Email]
[Show Entire Topic]     [Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy