Honda Twin Three Phase Alternator Project
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 13
Like Tree2Likes

Thread: Honda Twin Three Phase Alternator Project

  1. #1
    Senior Member Sonreir's Avatar
    Join Date
    Apr 2010
    Location
    Albany, OR
    Posts
    603

    Honda Twin Three Phase Alternator Project

    Many of you know that I've been tinkering with this idea for a while. The Honda twins don't often generate enough power at idle, which really kinda cramps my plans for an EFI system at some point in the future.


    So... time to solve the problem of anemic charging. When it comes to alternator/generators, three things affect the output.

    1. Strength of the magnet in the rotor
    2. Number of windings in the stator (affects voltage)
    3. The thickness of the wire used in the windings (affects current)



    The easiest electrical option would be just to increase the strength of the magnets within the rotor. Unfortunately, new rotors would be difficult to manufacture and I don't want to get into the intricacies of milling out rotors to attach new magnets. We can still revisit this if we need to, but I decided to table it for now.


    So these leaves us with modifying the stator in some way. We made a couple of adjustments here. First, we eliminated three of the six mounting holes. This frees up room for more copper. Ultimately, the voltage and the current are going to be sort of a self-balancing situation, due to Ohm's law and the implemented voltage regulator, so we'll tweak those variables later, if needed. Basically, more copper = more power. Whether it comes as current or voltage, we'll worry about later. "Try it and see" is where I'm working from right now.


    Additionally, we've changed the number of poles on the stator from six to nine. By going with three groups of three, we can more easily implement a three phase setup. In a single phase setup, there are two output wires from the stator. Each wire represents one end of the circuit, and as the magnets approach, and then depart, the center line of the windings, voltage increases towards a maximum positive amplitudes and then reverses direction and reaches a maximum negative amplitude.
    Honda Twin Three Phase Alternator Project-1024px-simple_sine_wave.svg.png

    Three phase works a bit differently. There are three output wires from the stator. Each of these wires represent one end of a circuit, with the opposite end of each of the three wires, joined together into what's known as a star configuration. You can also wind three phase as a delta config, but I've opted for star since it's a little easier. Functionally, I'm not expecting a big difference between the two, but we can experiment later if this first go doesn't work out. Anyway... because of the configuration of the poles and the windings, there is never a point where zero power is being produced by the alternator. This should provide us with steadier output from the alternator and hopefully help overcome the charging issues from which these machines suffer.

    Honda Twin Three Phase Alternator Project-3phase.gif

    Got these stator forms water cut from some mild steel. A little bit of tweaking and they're a decent fit. Time to start winding some copper...

    Honda Twin Three Phase Alternator Project-20170518_165335.jpg

    Honda Twin Three Phase Alternator Project-20170518_181217.jpg

  2. #2
    Senior Member ancientdad's Avatar
    Join Date
    Nov 2016
    Location
    Inverness FL
    Posts
    771
    Quote Originally Posted by Sonreir View Post
    First, we eliminated three of the six mounting holes. This frees up room for more copper.
    While I like the idea (despite, personally, my brat not needing any additional charging power), I'm not sure that part will work - unless you can make different provisions for the alternator cover screws, which occupied the other 3 holes in the stator housing.

  3. #3
    Senior Member Sonreir's Avatar
    Join Date
    Apr 2010
    Location
    Albany, OR
    Posts
    603
    The same three screws for the cover will pass through the stator and hold both unit in place. I might need some spacers and/off standoffs, but I'll cross that bridge when I get there.

  4. Remove Advertisements
    HondaTwins.net
    Advertisements
     

  5. #4
    Member ajk4send's Avatar
    Join Date
    Apr 2016
    Location
    Silesia, Poland, Europe
    Posts
    31
    Quote Originally Posted by Sonreir View Post
    Many of you know that I've been tinkering with this idea for a while. The Honda twins don't often generate enough power at idle, which really kinda cramps my plans for an EFI system at some point in the future.


    /So... time to solve the problem of anemic charging. When it comes to alternator/generators, three things affect the output.
    Although idea is not bad, stator core construction should not be done from single piece of metal. This part of magnet circuit should be done from laminations (dynamo steel sheets covered by insulation) to get anisotropic resistance and reduce eddy currents and power losses due to core heating created by these currents. You can make this laminations from 0,5mm or 0,35mm dynamo steel. This material is avalaible in different quality, defined by magnetization curve and level of power loss at given magnetic field value.

    Here, in Poland, there is a workshop making improved power source for HD bikes. Approximate price for one lamination in Poland is ca 10 EUR (12 USD?). The lamination is laser cutted. Cheaper version can be done on stamping press, but huge production volume is required due to press tool price.
    Andrew JK, forward inclined rider,
    Granny Raspberry, Honda CB125 K5, '72,
    Silesia, Poland

  6. #5
    Senior Member Sonreir's Avatar
    Join Date
    Apr 2010
    Location
    Albany, OR
    Posts
    603
    Lamination is the plan for the final production version. We went with a solid piece, for now, due to budget constraints. If we can get it working with a solid piece, we should be OK for laminated.

  7. #6
    Senior Member Simo's Avatar
    Join Date
    Sep 2012
    Location
    New Zealand
    Posts
    3,914
    Sorry for my electrical ignorance what happens after the 3 phase ac at the regulator are the 3 positive wires put together before the rectifier? Or are they rectified individually and the phases combined as DC?
    Blood, Sweat, & Gears
    Buy a Hondatwins T-shirt
    sales supporting 66Sprint's 2016 LSR Build

    http://www.hondatwins.net/forums/22-...d-attempt.html

  8. #7
    Senior Member Sonreir's Avatar
    Join Date
    Apr 2010
    Location
    Albany, OR
    Posts
    603
    They're rectified separately. Three phase regulator/rectifiers will have three wires of the same color.

  9. #8
    Senior Member Simo's Avatar
    Join Date
    Sep 2012
    Location
    New Zealand
    Posts
    3,914
    Would the stock set up benefit from a 3 phase rectifier? Are the stock stators true single phase with all the peaks and troughs aligned like your first picture or are they more like your 3 phase picture ( but minus the c wave?)

    Is the intention to put your unit into production ?
    Blood, Sweat, & Gears
    Buy a Hondatwins T-shirt
    sales supporting 66Sprint's 2016 LSR Build

    http://www.hondatwins.net/forums/22-...d-attempt.html

  10. #9
    Senior Member ashimotok0's Avatar
    Join Date
    Jan 2011
    Location
    East Yorkshire UK
    Posts
    396
    Interesting.. The 3-phase design on the 350/400/500/750 SOHC fours is brilliant IMHO . It uses a rotor of steel with magnetism induced by a stationary single coil, the rotor spinning outside of that 'field' coil and the three phase windings on the 'stator' mounted on the outside of the steel rotor which feed into a 3-phase rectifier . The beauty is that by adjusting the field coil current using feedback from the battery voltage etc using an electromagnet or solid state rectifier the alternator output can be continuously adjusted to suit the power demand and without the need for carbon brushes as used on early car alternators. Having said that, modern bikes appear use rare earth permanent magnets that will be far more efficient than their 70's counterparts. Some HD's have a 3-phase stator which has a steel cup lined with magnets that spins around the outside of the 3-phase stator.

    I love you kind of project and will watch with interest. I wonder how the standard system would be improved if a rare earth magnet rotor was designed and fitted?
    Last edited by ashimotok0; 05-20-2017 at 03:31 AM.

  11. #10
    Senior Member LiamG6's Avatar
    Join Date
    Mar 2016
    Posts
    350
    Following with interest, I like the fact that you are trying to keep it simple and implement just new windings with original magnet, should put this in a price range that people would be willing to pay for if you go into production. I'm personally looking at an electric oil pump to supplement top end oiling in my CB450 and a bit of extra wattage would really help that, about 30w is all I need so it can be done just by switching a lot of my lights to LED but I've always wondered about getting my coils rewound, a drop in 3 phase replacement would be great if it works, although I'd need a new R/R.

Page 1 of 2 1 2 LastLast

Sponsored Links

Posting Permissions

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