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20hp RPC to power 10hp planer HELP

I always get a ratio of .55 with run caps.
If one is 90uF then the other is 50uf.
This figure of .55 stays the same with increase of Hp.

You ratio is .94. Wouldn't be balanced in my world.
 
Can u explain how you get to .55 please. I don’t understand how 90uf gets to 50uf ? Sorry I probably don’t know something basic and how to ratio uf?
 
Also I was following this guide
 

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50 divided by 90 = .55
27.5 divided by 50 = .55

For 2 Hp:
C-13 = 50 uF
C-23 = 27.5 uF

For 5 Hp:
C-13 = 90 uF
C-23 = 50 uF

scaling that up for 20 Hp:
C-13 = 360 uF
C-23 = 200 uF

I'm not sure if the .55 ratio is a universal rule. But it works over here
with different motors to. I would probably consider a start for me at:
C-13 = 300 uF
C-23 = 150 uF

I never did any fine tuning of this stuff until the idler and target motors are both running.
And then swapping capacitors until I get voltages close. The .55 figure was always the mark.
 
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Hey everyone. I have an update on my phase converter build.
I addd some pictures that I hope might help make sense of what I’m writing and I tried to be as detailed as I could for y’all’s help? So I know it looks long winded but I wanted to give as much information as I could. And thank you for your help and feedback!
So I’ve mounted the electrical components of the RPC to directly below my 200 amp household service panel.
I’ve run #6 wire I got from a neighbor.
I’ve rerun that wire from the breaker panel through a switch to my Run caps and #6 from those terminals to the pony breaker and from that directly to the pony motor itself.
I have #6 from the same spade terminals (of the caps) as that of the incoming power and to the outgoing 3-phase breaker for the machine I’m trying to run.
I’m still using #10 wire to link the Run caps in series and I’m using #10 from the outgoing side of the run caps to the Ghost leg terminal of the Pony motor breaker. And #10 wire from that Ghost leg terminal to the L2 generated leg terminal of the outgoing 3-phase breaker terminal.
And I’m still using #10wire to ground everything.

Now for the update in performance…..
The Pony motor starts up much easier now and lights don’t dim when I start it.
I had to rebalance the Run caps for L2 and the ghost legs to be almost equal and about 9% greater than the original 243Volts on L1. Here’s those numbers
L1 - L2 =243
L1 - Ghost =263. Caps=163.5 mfd
L2 - Ghost =261. Caps=335 mfd
Is the difference in mfd between L1 & L2 matter if their balanced like this?
I upgraded the breaker from 50amp to 60amp. Which was the biggest I could find at Lowe’s
I thought about adding a 25mfd run cap between L1and L2 but held off for now bc the instructions I was following said to do that after I put the load on the converter.

So some questions… 1rst I let the converter motor run for about 5min before I tried to start the machine (which is a 10hp Planer) and it failed to start. Or it’ll start to start and work up to speed but then pops the breaker.
Also afterwards I noticed the Pony motor was getting hot especially on the end with the arbor. Is that normal for such a big motor?
- Next is it necessary to change the #10 wires that link the run caps together?
+And is the #10wire from the caps to the ghost leg and from the ghost leg to the out going 3-phase not enough?
The reason I didn’t change all is bc of the issue of connecting #6wire to the run cap spade terminals
- And can/should I change the 60amp breaker out for a 100amp breaker and is that ok to do in the same household service panel which is a 200amp service?
I had a hard time finding an answer to that question online , all I could find is “how to’s” on putting in another service panel which is not something I want to do bc of cost.
- I’m great full for all feedback and if there are better ways to connect larger wire to the run cap spades please let me know?
-also any more explanations on the.55 rule for balancing with the run caps or if the directions I’m following for balancing the generated legs are ok ?. And the directions I’m following are the ones found here and that I see used for YouTube videos. I’ll try and add that photo as well.
***all wires in blue are #10 wire and 1 red one on the right side of the box.
 

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The motor is getting hot because it is saturated and producing 263volts.

You can move the capacitors to the load, so they are only in the circuit when the planer is running.. the only problem being you will want a serious knife switch so you dont blow up the contactors. The inrush current is pretty high.
 
Thanks brother. Can u explain what you mean by moving them to the load side though?
putting L1 &L2 from the switch directly to the pony motor breaker?
But do I still run a wire from pony breaker to the caps as well ? Or only the 3 wires coming from the ghost leg terminal of the pony breaker to the caps and then to the outgoing 3-phase ?
Or would it only be 2 wires from the ghost leg of the pony breaker to 1 side of the caps and then from the other side directly to the outgoing 3-phase ?
 
Sorry. I think I see what you mean.

So basically move 2 of the wires from the pony ghost terminal to the L2 generated terminal of the outgoing 3- phase breaker?
 
Remove some of the capacitors from the rpc, so that the no load voltage is 245 or so..

Take the capacitors you removed and install them on the planer's motor. In the same orientation.
 
Oh. Crap. I don’t know if I can. It has its own thermal protections and all kind of other stuff. Here’s a pic of where you connect incoming power. Behind this is the motor.
 

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Also do u think this will help to get enough power?
Can / should I replace the 60amp breaker with a 100amp breaker?
Also I’m not using contractors bc I did almost break one when I put the 60amp breaker in. It closed and wouldn’t break the circuit but I took it apart and put it back together and it still works but yeah , it couldn’t take the amps.
So if I balance all 3 legs to be about what the incoming is,243-ish, and take the caps that I disconnected… can I put them , say, after the outgoing 3-phase breaker ? I’ll add a photo…..
And actually how would I do that ?
Sorry if I’m not getting it and I REALLY APPRECIATE y’all’s help !
 

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wheres the start caps? all I see are run caps which dont help the dead leg...... why not just spend the $500 on a pre built box with everything in it?

#6 wire on a 20HP motor isnt enough. need large enough to support 100A which is #2 wire . the output to whatever you power needs #6

this is why you buy crap that you dont know about, and pay someone for things you don't know how to wire.

like the breaker that has 60A for a motor under start up that pulls 150A!

and this is why electricians need to be licensed..........
 
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The start caps are in the small box above the main converter panel.
And I can’t afford the $500 or more and I like trying to build one and learn from it.
If I can figure this out , I’ll be able to build on this project for something else.
 

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Does anyone have some ideas of getting the planer to run on the phase converter I have please.
And Jahansen you’ve been great and I really appreciate your support. And your advice to move the capacitors to the motor.
My only question on that is…. Can I put that after the planet’s own thermal protection and other electronic components that are in the box before the motor? The way you explained it, it doesn’t seem like it would matter. Just thought I’d get what you think.
And to BT…. I would just say that I assumed that this forum was to help everyone learn and to ask questions of people who DO understand this stuff. I apologize if I’ve offended or misunderstood any input you’ve provided but I still appreciate your time in viewing my question/thread.
And I appreciate and try to absorb any knowledge and advice the professional here have to say and I value your time very much.
I’ve been reading over any thread that has to do with RPCs for months now and I tend to over complicate the theory and actions to put this into practice. So I try to fully understand each step in the process. And I have a hard time understanding the why of why this isn’t powering up the planer and what I need to do from here to make this work ?
There are pictures above of the box I’m talking about in the planer.
Thanks
 
Does anyone have some ideas of getting the planer to run on the phase converter I have please.
And Jahansen you’ve been great and I really appreciate your support. And your advice to move the capacitors to the motor.
My only question on that is…. Can I put that after the planet’s own thermal protection and other electronic components that are in the box before the motor?

By removing the caps from the rpc, and placing them directly in parallel with the planer motor.. you will slightly reduce the current flowing through the motor contactors and overloads at turn on. It may not make any difference but the whole point of doing this is to make the rpc useable for other loads.

you can also add additional start capacitors from line 1 to line 3, in the planer, on their own potential relay.

as for the undersized wiring and overloads... Bigger wires means more voltage means more current flowing. It may not help.

Another possibility is to get 2 buck boost transformers and run your planer off 208-208-230vac. You leave the rpc alone, it continues to produce 240vac line to line.

But you buck the two pass through legs 16 volts each from 240. So the planer sees 208 from the utility but 230 from the rpc.

This will reduce the starting current without reducing the startup torque much, because the rpc is your limit. The generated leg produces a current not a voltage in a sense, and if you measure the voltage on the rpc, measured from generated leg to neutral, it will be 208 or higher at no load but collapse to maybe 50vac when the planer is started. So the planer is seeing 240 on one phase and 50 vac on the other which is why it takes so long to start and then trips the overload.

Get yourself a clamp amp meter and measure the current flowing on line 3 at startup. It may not be all that high.

A friend of mine has a 20hp rotary and the impedance of the generated leg is 0.8 ohms. At 100amp draw, the 208 measured line to neutral should collapse to around 110vac.. i have not verified that. I know it will collapse (or increase) 50 volts ac in responce to 70 amps.
 
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Does anyone have some ideas of getting the planer to run on the phase converter I have please.
And Jahansen you’ve been great and I really appreciate your support. And your advice to move the capacitors to the motor.
My only question on that is…. Can I put that after the planet’s own thermal protection and other electronic components that are in the box before the motor? The way you explained it, it doesn’t seem like it would matter. Just thought I’d get what you think.
And to BT…. I would just say that I assumed that this forum was to help everyone learn and to ask questions of people who DO understand this stuff. I apologize if I’ve offended or misunderstood any input you’ve provided but I still appreciate your time in viewing my question/thread.
And I appreciate and try to absorb any knowledge and advice the professional here have to say and I value your time very much.
I’ve been reading over any thread that has to do with RPCs for months now and I tend to over complicate the theory and actions to put this into practice. So I try to fully understand each step in the process. And I have a hard time understanding the why of why this isn’t powering up the planer and what I need to do from here to make this work ?
There are pictures above of the box I’m talking about in the planer.
Thanks
Im just saying, is that you are further ahead to just spend the $500 once, as all the components you need to make it run properly and safely will be the same if not more then just buying a box with everything already in it. you will just be months ahead if you really want it to work.
Overall its really simple but one wrong wire, one MFD cap off and nothing runs. hard to just explain all the complexities of it over the internet without you having a oscilloscope and the knowledge to use it safely without blowing it up. Can read a ton, and maybe get it, but there are small details of it all that nobody says anything about.
Just judging by the wiring pictures kinda says alot. Good parts cost $, like some contactors alone can be $100 each.
 
Update……
Added a 100amp breaker and lowered capacitors so the generated legs are around 255volts. So the pony motor isn’t getting as hot.
With these changes the planer finally started up and ran.
Sorry I didn’t see y’all’s response until after I did this so I will look into that. I’m going to do some more studying on the parts and how to implement them that Johansen suggested.
And I appreciate your input BT. I did look at some boxes from American rotary and they were significantly more than $500 bucks. I thought it was closer to $1500 but I’ll look again and maybe I’ll call them to make sure I’m looking at the right thing.
Maybe a stupid question but are you talking about the static converters and can you add a motor to them with some modifications ?
When I used the amp clamp meter. I did get some weird amperage. I think L1 had
25-ish amps , L2- was 18-19amps and I can’t remember L3 and that was with the planer on and the feed roolers on engaged.
I was checking voltage between legs but not to ground or neutral . I’ll do that next and I’ll write all that down so I can share it.
And yeah BT , it’s the nuance that I was worried about. And I understand that this is a hard medium to explain those details that come with understanding electrical theory and working experience. I definitely have had a hard time wrapping my head around Alternating Current(AC). And when wiring the ghost legs and the capacitors.
For example when I mocked everything up on a piece of plywood and I had all these connections originally made to some terminal connectors and then trying to remove those to connect them to the capacitor spades , that kind of through me for a loop. DC current seems much simpler to me. Hahaha.
Hey thanks guys soooo much for your help,advice and responses. Just going through the thread process and explain everything and the responses has really made a difference in my understanding and hopefully it’ll help someone else out.
 
. I think L1 had
25-ish amps , L2- was 18-19amps and I can’t remember L3 and that was with the planer on and the feed roolers on engaged.
I was checking voltage between legs but not to ground or neutral . I’ll do that next and I’ll write all that down so I can share it.
the only reason i mention the generated leg to neutral voltage, is because it tells you what the contribution is of the generated leg with just one voltage measurement. you know the line stays at 120/240. leave the volt meter connected generated leg to neutral and watch it drop as you start the planer.

you need an amp clamp meter on the 3 legs to determine your margin.. its easy to overheat a motor with unbalanced line voltages and currents.

motor rated hp drops with the square of the supplied voltage... you'll see this reflected in the nameplate of a 10hp 1.25 service factor 240v motor.. it will read "useable at 208" and what that means is.. you can use it, but it will have no service factor. try to pull 12.5hp out of it on 208 it will burn up. but at 240v it won't.

running your planer on 208-208 - (whatever comes out of the 240v rotary) will make it electrically similar to an 8hp motor and it should start easier and draw less current. you probably don't need to do this but if your wiring is substandard and your overload is blowing then it will draw less current and may "just work" obviously you want to ensure you don't burn up your wires, or motor, overloading it.
 








 
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