Free 50 Best Homemade Tools eBook:  
Remove advertisements
Page 22 of 23 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 LastLast
Results 211 to 220 of 223

Thread: Rotary Phase Converter (Create 3-phase power from a single phase source)

  1. #211
    Frank S's Avatar
    Join Date
    Aug 2015
    Location
    Peacock TX
    Posts
    2,066
    Thanks
    361
    Thanked 2,015 Times in 972 Posts

    Frank S's Tools
    I'm done with this thread.
    Never try to tell me it can't be done
    When I have to paint I use http://kbs.justoldtrucks.com/

  2. #212

    Join Date
    Oct 2016
    Posts
    43
    Thanks
    0
    Thanked 0 Times in 0 Posts
    Frank S,
    So am I.

  3. #213
    nhengineer's Avatar
    Join Date
    Aug 2016
    Posts
    101
    Thanks
    0
    Thanked 26 Times in 14 Posts

    nhengineer's Tools
    Me three.

  4. #214

    Join Date
    Jan 2017
    Location
    Kansas
    Posts
    12
    Thanks
    0
    Thanked 2 Times in 2 Posts

    Curious

    Could I trouble you for a quick question? I have acquired a 1950 era American Tool Works Pacemaker lathe 16x54. It is powered with a 10hp 3 phase motor and i have yet to trace all of the 'thingies' in the electrical box to know what is what as it has 5 wires in the cord the previous owner cut to keep the end. I have used rotary phase generators for over a decade as my mill is 3hp 3phase and my cincinatti pressbrake is 5 or 7hp (just can't remember at the moment) 3 phase and 3 phase isn't available on the farm. With all of that said, I've always been told a rule of 1/3rd, generate 1/3 more hp 3 phase than required to have the power to power the machine. My first generator was an old 5hp 3 phase that was the size of a small car engine and I'd pull start it with a short rope. All was fine until I got the new to me Cincinati Press Brake and I needed more power, it would blow my fuses before the pressbrake could get up to speed. I came across a 10hp 3phase for around $25 and I rewired this time with pony motor.. Now I have a 10hp lathe to get going.. I first aquired a 45hp GIANT 3 phase motor I thought was a good idea, I was informed i had made a mistake and I have yet to.... Last week I found a nice 15hp 3 phase motor I'm hoping can power the lathe. What would you suggest? Is the 15hp going to have the power to get the old girl (lathe) spinning, or should I?

    Jeff

  5. #215
    Frank S's Avatar
    Join Date
    Aug 2015
    Location
    Peacock TX
    Posts
    2,066
    Thanks
    361
    Thanked 2,015 Times in 972 Posts

    Frank S's Tools
    Jeff I can't speak for MR. rhengineer but I would say that 15 hp 3 ph motor started with a 3/4 to 1 hp pony motor such as his plans describe would be more than adequate to start your 10 hp lathe. However there are other ways you mentioned your generator is is already a 10 hp with pony motor start you might try adding an additional 5 hp 3 ph idler motor to your existing unit just wire it in with a contactor and switch it on once your generator is running adding 70 to 100 Uf per hp run capacitors between 1 leg of the input and the 3rd leg of the generator helps to smooth out the phase angle as well
    Rotary Phase Converter (Create 3-phase power from a single phase source)-phase3.jpg
    My generator is a 3 hp cap start cap run no pony motor unit that I run my 3 hp Leblond on I really need a 5 to a 7.5 Hp motor on the lathe but haven't gotten around to building a larger generator yet but I have on occasion ran both my lathe and my 3hp mill at the same time on the single 3hp generator by starting the lathe first. I also find that if I let 1 machine run idle I can make heavier cuts with the other than I could by having only a single machine running.
    Another thing you could do unless you are really trying to make monster hog off chips would be to resize the motor on the lathe to 7.5 hp as I said my Le blond is running on 3 hp but it is also a 17" swing lathe
    I have a set of rhengineer's plans and will be constructing my next generator bases in part on his plans with some additions of my own
    Last edited by Frank S; 01-30-2018 at 06:57 AM.
    Never try to tell me it can't be done
    When I have to paint I use http://kbs.justoldtrucks.com/

  6. #216
    nhengineer's Avatar
    Join Date
    Aug 2016
    Posts
    101
    Thanks
    0
    Thanked 26 Times in 14 Posts

    nhengineer's Tools
    Quote Originally Posted by JeffEck View Post
    Could I trouble you for a quick question? I have acquired a 1950 era American Tool Works Pacemaker lathe 16x54. It is powered with a 10hp 3 phase motor and i have yet to trace all of the 'thingies' in the electrical box to know what is what as it has 5 wires in the cord the previous owner cut to keep the end. I have used rotary phase generators for over a decade as my mill is 3hp 3phase and my Cincinnati press-brake is 5 or 7hp (just can't remember at the moment) 3 phase and 3 phase isn't available on the farm. With all of that said, I've always been told a rule of 1/3rd, generate 1/3 more hp 3 phase than required to have the power to power the machine. My first generator was an old 5hp 3 phase that was the size of a small car engine and I'd pull start it with a short rope. All was fine until I got the new to me Cincinnati Press Brake and I needed more power, it would blow my fuses before the press-brake could get up to speed. I came across a 10hp 3phase for around $25 and I rewired this time with pony motor.. Now I have a 10hp lathe to get going.. I first acquired a 45hp GIANT 3 phase motor I thought was a good idea, I was informed i had made a mistake and I have yet to.... Last week I found a nice 15hp 3 phase motor I'm hoping can power the lathe. What would you suggest? Is the 15hp going to have the power to get the old girl (lathe) spinning, or should I?

    Jeff
    Hi Jeff. The 'rule of thumb' you mentioned is what I use as well. Since the idler only has two hot legs, it's only capable of 2/3's of its nameplate HP rating; perhaps even a bit less depending on age and efficiency. I would recommend you add together all the 3-phase motors that will be running at the same time (maybe there is only one), multiply that value by three and then divide by two. That puts you in the ball park. Then pick the next higher standard HP idler. That gives you the absolute minimum HP you can use.

    The multiple conductor cord may indicate that the motor set-up is reversible. Any 3-phase motor can be reversed simply by switching any two of the three output conductors FROM the 3-phase converter. This can be accomplished using a 'two pole - two throw' toggle rated for the load. Remember to let the load motor idle down to 0 RPM before switching. Write back if you need a schematic.

    I hope the above is helpful.
    David Lee

  7. #217

    Join Date
    Jan 2017
    Location
    Kansas
    Posts
    12
    Thanks
    0
    Thanked 2 Times in 2 Posts
    Gents, thank you for your responses. I may be daft, but am I understanding that I can run more than 1 idling generating 3 phase motors in the system to even out the phase out-of-sync? I think I understood the adding of all the motors that could run at the same time and generate from that level of hp requirment 2/3 rule.
    I would appreciate any schematics/idiot guides you have to offer. I have a 3 or 5hp #22 Buffalo Forge drill press, Bridgeport Clone 3hp, Cincinnati 35Ton press brake 5 or 7hp, and now my new lady (my wife is understanding of a mans needs) 10hp Pacemaker lathe.

    I am also in process of semi-automating my Straight guillotine bandsaw, using limit switches, contactors, momentary push buttons to make the hydraulic lift go up to an adjustable height to make for quicker operations and less over lifting or thinking on my employee when they are cuting many parts of the same sized material, it will move up and down on a shaft collar running on the dual posts that hold the saw 'head'. Also adding built in lighting and control of coolant pump to be automatic with the saw motor. The last part of that system is a switch to manual so that if something breaks you can still just flip a couple switches and it will still work..

    Many thanks!!

  8. #218
    nhengineer's Avatar
    Join Date
    Aug 2016
    Posts
    101
    Thanks
    0
    Thanked 26 Times in 14 Posts

    nhengineer's Tools
    Quote Originally Posted by JeffEck View Post
    ......am I understanding that I can run more than 1 idling generating 3 phase motors in the system to even out the phase out-of-sync?
    For the record, I did not recommend that. I do not know if it would work out or not.

  9. #219
    Frank S's Avatar
    Join Date
    Aug 2015
    Location
    Peacock TX
    Posts
    2,066
    Thanks
    361
    Thanked 2,015 Times in 972 Posts

    Frank S's Tools
    Quote Originally Posted by nhengineer View Post
    For the record, I did not recommend that. I do not know if it would work out or not.
    Some food for thought. if you already have 1 rotary converter with or without the starting assistance of a pony motor you can parallel in idler motors till kingdom come as long as your line amperage is sufficient to handle the per phase load amperage of the equipment which is going to be run off of the converters.
    I often use the motor on my end mill as a booster idler for when I need tr run heavy loads on my lathe and vice versa. I do this because my converter is the same size as the motors on the lathe and the mill which means either must be started under no load. Ideally I would have a 5HP converter.
    Here is a chart which shows the maximum amount of installed HP which can be run on a given sized converter as long as all motors are lightly loaded and not started at the same time. the chart also describes how multiple converters may be linked together for starting larger motors
    RMU (1).pdf
    If I had some large capacitors I would be tempted to see if I can get my little 3 hp converter to start an 8 hp inverter rated motor that I have and allow it to run as an idler in parallel to see if I would have sufficient power to rower up a 240 to 480 v transformer that is needed to run my 7.5 HP Cleereman index drill now that the electric co has installed new 2 ought feeder lines to my meter as opposed to the old #4 AWG lines I had before. I might have to add a 3 hp idler before the 8 hp but that would or should according to the chart give me the equivalent of a 14 HP converter
    Last edited by Frank S; 01-30-2018 at 06:26 PM.
    Never try to tell me it can't be done
    When I have to paint I use http://kbs.justoldtrucks.com/

  10. #220

    Join Date
    Jan 2017
    Location
    Kansas
    Posts
    12
    Thanks
    0
    Thanked 2 Times in 2 Posts
    I went back and reread it, I totally got both responses all mushed in my head... Been a long day, I started at 2:45 am as I couldn't sleep last night, although most days I get to the shop at 4am... Early bird, worm, yeah I'm still trying to find the worms...... Thank you for correcting me, makes much more sense when given a second read and it soaks in...

Thread Information

Users Browsing this Thread

There are currently 2 users browsing this thread. (0 members and 2 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •