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  1. #61
    Community Moderator Jim Dawson's Avatar
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    Default Re: fine tuning my self built 10hp phase converter.

    Don't worry about the L3-GND voltage. But you should have the controls (transformer primary) connected to L1 and L2. 129V is a bit high, but should work fine. Let's see what it looks like with the motor running.

    The loaded phase to phase voltage is what is important, looks like you are pretty close. Once you get the motor running then check the phase to phase.

    Jim Dawson
    Sandy, Oregon, USA


  2. #62
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    Default Re: fine tuning my self built 10hp phase converter.

    ITTTTTTTTTTTTTT'SSssssss ALiiiiiiiiiiiiiiivvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvee e

    I can't believe it the damn thing works.Another thing I can't believe is I had it hooked up just like you posted all accept I didn't pigtail a wire off of that secondary wire to the 96 terminal on the O/L. I tried it and it started in for but wouldn't go in rev. The contactor would lock in but nothing happened. After looking at it real close I saw the problem. I had the jumper wires between the two contactors on the line side reversed just like the old one was and after looking at your drawing I saw that they needed to be reversed on the load side. The problem with that is how do you hook up the overload relay the way they hook up to the one contactor? I know they make a wiring block just for that and I thought I had one but never found it. Well it wont easy to do and it took a fair amount of colorful language but I finally came up with a jumper system that ain't very pretty but it get's the job done. I'll post a pic when I get done wiring it all up, right now it working mostly off jumpers.

    I took some more readings after getting it running with the spindle turning and they look like this now. L1 to L2 238 v.....L1 To L3 218 v........L2 to L3 232 v

    L1 to gr 119 v
    L2 to gr 119 v
    L3 to gr 188 v

    With the voltage at the coil at 128 v

    I also checked the current draw on each line.
    L1 6 amps
    L2 6 amps
    L3 3 amps

    Let me know if that sounds ok or if I need to do some more tweaking on the capacitors. The RPC starts really fast less than a second maybe two to get up to speed and there is very little deflection on the amp probe from normal running amps.

    Although I hate to get the bill on this one though



  3. #63
    Community Moderator Jim Dawson's Avatar
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    Default Re: fine tuning my self built 10hp phase converter.



    For the contactor to motor wiring with a single O/L look at my drawing in post #46, It shows how to connect it. The phases are reversed on the line side, but connected the same on the motor side.

    A little more tuning might be required. Odd that L3 is 3 amps, but you may be getting some weirdness with the power factor. If you aren't using a true RMS meter, it may not read exactly correct when the power factor is a bit wonky.

    To explain power factor a bit, with a resistive load (electric heater for instance) the current and voltage are in phase with each other or 100% power factor. When you are running a motor (inductive load) then the voltage and current are out of phase a bit, around 85% power factor, now add in some capacitance and it can really affect the power factor. Adding exactly the correct capacitance can correct the power factor to 100% on a motor load. But if the capacitance is way high (or low) the power factor can be quite low. Bottom line is don't worry about it too much for now.

    Jim Dawson
    Sandy, Oregon, USA


  4. #64
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    Default Re: fine tuning my self built 10hp phase converter.

    Quote Originally Posted by Jim Dawson View Post


    For the contactor to motor wiring with a single O/L look at my drawing in post #46, It shows how to connect it. The phases are reversed on the line side, but connected the same on the motor side.

    A little more tuning might be required. Odd that L3 is 3 amps, but you may be getting some weirdness with the power factor. If you aren't using a true RMS meter, it may not read exactly correct when the power factor is a bit wonky.

    To explain power factor a bit, with a resistive load (electric heater for instance) the current and voltage are in phase with each other or 100% power factor. When you are running a motor (inductive load) then the voltage and current are out of phase a bit, around 85% power factor, now add in some capacitance and it can really affect the power factor. Adding exactly the correct capacitance can correct the power factor to 100% on a motor load. But if the capacitance is way high (or low) the power factor can be quite low. Bottom line is don't worry about it too much for now.
    I had wired and rewired this thing so many times without any positive effect it was effecting my sleep. I don't know how many days I just sit there looking at that old control changing this, changing that all with the same results until I decided to scrap that whole control. I know you told me to do that many pages ago but, I am hard headed you know. What really caused me so much pain is the fact that I know it was working the day they unplugged it. Then when I plugged it in to my system it wouldn't. Add to that, this is the first time I ever attempted to build a RPC and I was having a hard time with getting the basics down. There is so much good and bad information out there sometimes it's hard to really know which is which. On top of all that throw in all the problems I had with those cheap parts that came in the kit I bought everything just led up to a big bag of mixed problems.

    Im not really sure if any of the meters I have will read true RMS. I have an old Fluke 8020 B, a TPI 133 kit I bought for AC work, I have a MT 586 B that I bought from the snap on guy when I was working on boat motors that has all the bells and whistles, temp probe, and a bunch of other stuff I don't even know what it's used for. And of-course I have my old trusty Simpson 260 that always seems to be there when I need it. But for checking current I mainly use my old Amprobe clamp on meter. It will measure up to 600 volts and 300 amps and also ohms. That's the one I used to take the amp measurements.

    I would like to one day to get this RPC a little closer with respect to line voltage as well as power factor. I have struggled with trying to get my head wrapped around how to accomplish this but the way this kit I bought is wired I keep coming up blank. There are only 4 capacitors in the whole system, 2 on the start side and 2 on the power side that are all wired together . One thing it does do well is start up this machine will be up and running before you can take your hand off the start button. Maybe they figured that if it started that was good enough and you won't supposed to worry about the rest.

    I can't say enough again of how much I appreciate you hanging in there with me with getting this mess sorted out. Thanks!

    Attached Thumbnails Attached Thumbnails fine tuning my self built 10hp phase converter.-super-service-control-rebuild-002-jpg   fine tuning my self built 10hp phase converter.-super-service-control-rebuild-003-jpg   fine tuning my self built 10hp phase converter.-super-service-control-rebuild-004-jpg   fine tuning my self built 10hp phase converter.-super-service-control-rebuild-005-jpg  

    fine tuning my self built 10hp phase converter.-super-service-control-rebuild-006-jpg  


  5. #65
    Community Moderator Jim Dawson's Avatar
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    Default Re: fine tuning my self built 10hp phase converter.

    It's my pleasure to help out The good news is that you have it running.


    I wish you were close to me, I have a job that would be perfect for that DP. I have a couple of 1 inch thick plates, about 20 inches tall x 12 inches wide that need four 3/8 holes drilled & tapped in the top. Not enough clearance in my mill to do it, so going to have to do it on my Harbor Freight DP. Going to have to add a bit of support to the table.

    Jim Dawson
    Sandy, Oregon, USA


  6. #66
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    Default Re: fine tuning my self built 10hp phase converter.

    Yeah that will probably give that Harbor Freight DP a good work out prolly take longer to beef up the table than it will to drill the holes I still have to find a decent manual for that DP so I can figure out how to do the maintenance on it. I think I probably would like to change the oil in the head and spindle feed unit. It has sight glasses on both units but the glass is so stained I can't tell if there is even oil in them.

    Thanks again and I promise you if I ever run across another one of those grinders I'll save it for you and get it to you somehow.



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fine tuning my self built 10hp phase converter.

fine tuning my self built 10hp phase converter.