Home built rotary phase converter for home shop 3 phase power
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- čas přidán 5. 09. 2024
- In this video I gut a rotary phase converter and rebuild it from the ground up.
Some resources that I used while building:
www.practicalm...
• Building a Phase Conve...
www.laserfx.com...
Here are some links to some of the supplies that I used in this build:
www.amazon.com...
www.amazon.com...
www.amazon.com...
www.amazon.com...
That was one of the best explanations on a rotary phase converter I think ever thanks for taking the time to share your expertise with us
Great job! The one I built is a single push button start with different valued run capacitors to balance the load.
At my first (full time) job we were in a single phase only area. To run the machines that were three phase we had a motor (the converter) that I believe was three phase. We would spin the shaft with our foot (It had a rubber sleeve on the shaft) until it got spinning fast enough to start (with single phase). It would then somehow (I never learned how it was wired) run the triple phase motors with no problem. Kinda hack, but it worked well. This was in 1980. I remember John Lennon's "Imagine" was playing on the radio every day. It was just after his assassination.
Great video, and simple overall. The big thing is the maths for the capacitors and having the ability to start/run the pony motor from a reliable single phase source with enough amps for the voltage not to drop. Sadly lots of places still only have access to low amp connections or had contractors build to min spec connections so you can't even upgrade without selling your soul haha
Thank you for this excellent explanation
Glad it was helpful!
Here is what I did, the most simplest 3-phase motor in the world. Each pair reads 220 Volts..
Take one of them LG washing machine BLDC motors that people just throw out because people don't know how to fix their washing machine or any other washing machines that use them motors. Toss out the Hall sensors, you won't need them.
Now you have the three wires that are there. Install a pulley on that outside big old drum rotor using another motor, be it 120 or 220 or hell if you don't mind the noise run a gas engine. Whatever you do. You will find out that them three wires that are hooked up on the stator of that motor will give you nice and even three phase power.
The horse power you expect is the horse power you use with the engine turning the damn thing. There is your three phase supply. These motors are obviously delta phase. If you want Star/wye, it is easy as pie. Just take the drum out and rewire the stator to wye configuration in 10 minutes. Cheers.
This is amazing!!
A couple of home made phase inverter unit that I have seen in the past, there was a hand wheel mounted on the shaft of the motor that you would rotate by hand when starting the inverter.
Not a bad idea, although I think I'm pretty close to self starting. Going to be doing another project soon then getting back to this one.
@21:19 You should have put down a can of Red Bull (Original Flavor) and said, "Oh, this is just a Red Bull, this goes into YOUR circuit (Body). Red Bull is not required for this to work properly". ;-) Great Video! I love watching people do things that I am not quite sure how to do. Keep it safe people!! :-)
Great vid I really like how you built it up form the basics TY
Very nice video.I think for every one horse power you need like 90mfd capacitor you need about 2000mfd to 2700mfd of starting capacitors.Thats what I used on my 30ph and it starts up instant.
I thought it was all to do with phases across the start winding. Different capacities will vary the phase angle. How does motor power affect that equation?.
@@greenpedal370 Start caps "charge" the phantom leg so the motor doesn't single phase at start up.
@@Peter-V_00 Thank you.
You're correct my brother
good job. I built my 15hp RPC I used a timed Temp switch to fire the start caps. so I dont have to hold 2 start switches . Im looking for a fuse panel now to switch to all machines being on a breaker. that way lightning or a power surge wont fry all my machine motors.
I was looking at a voltage sensing relay to add into the circuit and control the start capacitors.
Thanks for your input. I need to build a 3 phase converter for welding shop. Three welders, air compressor, mill, & band saw. Can you suggest where I can learn more about the requirements & where to purchase components ? I have access to 25hp & 50hp motors. Thanks
a potential relay will do the start caps for you
@@TheArsonsmith4242
@@leesullivan7635 that is the route I went, with a potential relay and has been running for about 20 years now. it any pretty though. Only about 3 hp though.
I see you used sbirdranch as source. He has a very good tutorial. I used his tutorial to build my 5hp RPC. I like his single switch to charge the capacitors, and start the motor. The only problem I had was I blew a start capacitor. Replaced it with 3 start/run capacitors. All three legs are within 5 volts of each other. It was fun and fulfilling to build my own unit. Building a 30hp would be a bit of a challenge. Congratulations on your success.
Recently bought a 15hp motor to upgrade my power capacity. Will be building a new 15hp RPC. Just need to start aquiring my capacitors, etc. Are you engaging the start capacitors before the start button. I hate what I will have to pay for an empty Hoffman panel.
In the long run would be cheaper and a lot more convient to just get a 200 amp 3 phase service installed. Back in the early 1960's helped my sparky dad wire in a machine shop that only had a 2 phase 5 wire service. Took machine shop owner a year to get a 2.phase Bridgeport. He had us install a phase changer for a couple of new 3 phase machines. Went back a few years later to install another phase changer. Nice vid.
I looked into it and it would be $22,000 to run the service, then I would have to pay a premium on the monthly usage as well. This was not an option. Building this phase converter was between $6-800 worth of parts found on craigs list. Even a similar commercial converter would be around $2300.
Congratulations, its Amazing!!!Please help me, I'm trying to make a phase converter but it's not working, I even burned my engine. On the table you have a contactor, how many amps is it? on the contactor side, what equipment is this? This is where you connected the energy that is coming in (both phases) and last thing, I have two wires in my house that come from the street with 127v for each phase, Sir's is also like that, correct?
Very grateful🎉🎉🎉🎉🎉🎉
L14 is a 240V split (single) phase. L15 is the correct connector for three phase. But people use the L14 because it is cheaper.
To help with start-up add another contactor to take the balancing capacitors out of circuit until the converter motor spins up. The way you have it wired now you have capacitors connected off of both hot legs to the ghost all the time making it hard for the motor to start in the right direction.
What you're saying makes sense to the issues I am having. I'm about to do a lessons learned rebuild and update of this guy and hopefully update with one button start as well.
If you’re making changes, I’d suggest that once it starts reliably, it would be less complicated to run if you replaced the momentary switch for the starting caps with a normally closed relay that has its coil powered from the ghost leg. Great video, thank you for sharing.
@@ianlevine273 That is the exact plan, actual found a relay that has both on and off legs that I can swap run/start capacitors and lower the inrush of starting it with the run caps already in line.
Static phase converters would have been the way to go.
If you're on a super tight budget they can work in a pinch. Not something to run full time with though.
You might consider checking your neutral connection in the main load center or having your local utility company check on their end, an unbalanced voltage between the 240, I think you had 121v and 118v is a sign of a high impedance connection somewhere on the neutral, or grounded conductor, an easy way to check is to clamp an amp meter on the ground wire above the ground rod on the out side of your house and see if you have a load, if you do it's a problem.
Working with an elechicken/engineer now. Found my shop wiring is in pretty bad shape overall so going to have an entire new circuit pulled into the building. Will also be using the rotary phase converter to power an actual 3 phase load center and distribute to the shop as if it was utility supplied 3 phase.
Okay, so your ground is just there as a precaution incase an energized conductor comes in contact with something it's not supposed too, the purpose is to make the breaker or fuse open quickly, a ground otherwise is supposed to be a non current carrying conductor. You're neutral, or the proper term on single phase is grounded current carrying conductor, in a 120 volt application will carry the same current load as the energized conductor, on 3 phase it carries the imbalanced current load, so if your current is traveling somewhere other than the neutral, like say an improperly bonded ground, it can and will cause an imbalance in voltage unless the ground itself has a very low impeachable path to the neutral, and even than there can still be a voltage imbalance.
Replace the manual capacitor switch with a adjustable start up timer set to a 1 or 2 second delay to automatically cut off the start capacitor.
I did get a delay relay but for the past couple of years I've just lived with it the way it is. Slight inconvenience vs pulling everything apart and shutting down the shop 3 phase.
Great video.
I think the two large cap banks, you use to raise voltage on the ghost leg need to be disconnected during initial startup. They are causing a back feed of "out of phase" current being fed back to your building mains.
I do have a plan to add a way to remove at least the same set that has the start caps.
TheArsonsmith4242 It's not the start caps, its the load balancing caps. You will need two more relays. One like the start relay (3PST), and another on that has DPDT operation. Wire the normally closed poles on the DPDT relay to connect (NC contact) to turn on the additional 3PST relay when the AC supply is turned on. Wire two poles of the new 3PST relay to apply the load balancing to the motor. When the DPDT relay is operated ( in parallel with start coil relay), it will deactivate the 3PDT relay, disconnecting the two load balancing caps, during a start operation. When the start operation is complete and the DPDT relay is deactivated, the load balancing caps will be re-applied.
I also suggest you add fusing protection in the switching/relay area. If you have a failure in that area you have a path of a lot on amps to flow and release the smoke.....
@@markcummins6571 a circuit breaker would be better
@@markcummins6571 Yes, I mean a contactor that will swap the start and run caps.
I'd avoid the second switch and I'd use the green start button for the second (starter) contactor if that button has two switch.
I’m thinking the single phase supply line isn’t large enough for the surge when starting the idler motor. It looks to me that you have a 50 amp outlet and that idler will pull way more than that just to get up to speed. How many amps does the idler pull when it is just idling with no load? Also you will need to watch the draw on the single phase as you start using bigger machines like your mill or lathe.
I have the parts to build my own 5 hp Phase converter, right now the only 3 phase machine in my shop is my big mill and I’m running it on a VFD for now. I have a 3 phase motor to run my small mill which is where I need the VFD for speed control.
I got an additional amp meter that I'll put on the inlet line. It should get me a better idea of what the draw is. The entire shop is unfortunately on a 50 amp breaker, so the start of the motor plus anything and everything else in the shop, garage and guest house, doesn't blow the breaker (unless something else is wrong or I'm running the heater) I'm working with someone now to see if there's better options for upgrading my home panel to a 400amp so I can run a larger sub panel for the shop.
Fix it quickly, attach a 1 horse motor to the conversation. Motor to start and drop off after rpm is accomplished
using a pony start motor is always an option. I'd like to have a fully self starting one though.
I have to admit, I was a little afraid to watch this video. Most electrical videos on CZcams are unsafe installs. You did a very good job of explaining each step and how it affected the system. Was getting scared through most of it till you brought out the enclosures! Overall great job. Suggest you change to a cable connector for incoming power instead of a conduit connector. One thing I'm not understanding. The systems I designed in the past were with purchased rotary phase converters and controls. I do not understand why you needed to add all the other capacitors. Was the voltage rating on the 30 hp 240 volts or was it rated 208/240/480? If the latter and wires were connected for 208 volts, that would explain the outcome you got and could be re-spliced from 208 to 240 volts. As far as starting issue, you might try taking the drain resistor out of the start cap circuit. It could be taking too much power to charge the caps and then start the motor. You could add a switch to if if you ever did want to drain it. Respectfully, Kevin
the capacitors help bring the generated leg voltage up. Just spinning the motor on singlephase will generate the 3rd leg but it will be really low (around 180v) by adding the capacitors you can bring that up to 240+ about 8% to account for voltage drop while under load.
TheArsonsmith4242 thank you for the response. Any thoughts on letting start caps stay charged? Does the 30hp have a 208v rating? Also, the way I calculate it, you would need 65 to 75 amperes of over current protection in order for it to start correctly. Thank you for your time. Respectfully,
@@KevinCoop1 interesting read on motor voltage: www.brithinee.com/technical-articles/240-vs-208-volts-do-motors-care/ 240 and 208 both use the same windings in the motor.
Right now the entire shop is on a 50amp breaker and that's shared with the rest of the lights and equipment. (way under powered but only occasionally trips) I am currently working on the building upgrades to take care of that issue.
Hi, I'm guessing that the motor you're using is wired delta configuration. I'm going to look at a 30hp motor to build my own but I'm wanting to start it using a start motor and switch to star so o can produce a stable neutral. The starting issue you have is that you need a no volt contactor powered off one leg of the 3 phase output. That way the capacitors will only cut in once the motor is up to speed.
One thing that I realized is missing: a centrifugal switch. Single phase motors with starting capacitors have built-in centrifugal switches in series with the capacitor to deactivate it when it runs at full speed. Three-phase motors, however, are assumed to already be hooked up to three phases and therefore do not come with centrifugal switches. But I believe you can add a centrifugal switch to the end of the arbor and hook it in series with the motor starting capacitor so as to avoid having to use a momentary contact switch to serve that purpose. This also allows the motor to start up by itself if power goes out and then comes back on. Please pass this suggestion to all who have built rotary three-phase converters.
Yes, for single phase motors this is the only way to detect that the motor as at speed. My plan when I revisit this will be to add in a voltage sensing relay to the third leg and use that to cut out the starting capacitors.
Nothing to do with phase angle.You need the right amount of MFD otherwise your motor won’t last winding are getting hot from the high amperage due to the slow start.There a chart on line for calculating the capacitors to the HP.
how slow is a slow start? Other than the occasional spinning backwards attempt the motor spins up in under a second.
Great video. I was never totally clear on how one of these worked. Now I know. Would there be any way to not have a manual switch for the starter circuit? At any rate, it's a pretty neat project that can save thousands if you can source a motor for a reasonable price and know what you're doing. This very definitely isn't a learn as you go type of project. It doesn't look that complex, but you could end up dead very fast touching something at the wrong time (especially after the capacitors were added since powering off doesn't mean it's safe). A lesser danger is burning up the motor you're trying to make the converter from or worse the motor in something you're trying to power with it.
Yes, and I'm working on that soon. Got the parts and should have a follow up video.
The diagram only shows two wires like the load motor is 110 or 120.
Three phase motor has 3 Plus ground. The three wires are known to me as L1 L2 L3.
Does the amp ring go around each one of the three wires.
In the diagram the black voltage input wire from the V A meter is connected to one of the wires with the amp ring around it right.
Is the red wire connected to ground. Do they get connected to one of the L wires. If so which one L1 L2 L3
This is a rotary phase converter. The motor is part of generating the L1 L2 and L3 by getting it started using single phase 240v regular home power. Using start capacitors to jump start the 3 phase motor, then run capacitors to balance the power across the generated leg. The 3 phase motor (meaning 3 coils) is running from a single coil then through the magic of induction it is able to run almost like a generator to create the other two phases.
In the end, the point of the video and a rotary phase converter is not to spin the generators motor, but to generate the power to be used by other motors (such as the band saw example in the video.)
Some circuit diagrams would help a lot.
This is great. My RPC came with my lathe. It is a home built job. It's a 15hp motor. It has caps to balance out the voltages but I think I can get them a lot better. Is there a formula for figuring out what cap values and how many to use to get a close approximation or is it all trial and error. I've watched countless videos on setting up an RPC but everyone seems to just gloss over balancing the voltages with capacitors. My lathe is a 10hp machine, and the 15hp RPC will start the lathe. I deally I'd like to go to a 20hp RPC but I've been watching around for a 20hp motor and it's been slim pickings. My 15hp motor is getting tired. I've been seriously considering buying a brand new RPC form American phase converters but damn, a 20hp is about $1400. Any help on the capacitor front would be greatly appreciated. Thanks
I am planning a followup video on the RPC build and I can add in some info on how to do it. Basically you have to add in a guessed amount of capacitors, start everything up, put it under load and then measure voltage. If it's too high remove caps if it's too low add some. Rinse repeat.
@@TheArsonsmith4242 I guess one of the main questions is how many capacitors to buy, to have on hand, and mfd ratings, should I get. I want to have this stuff here when I start so I don't have to wait around for the UPS guy to show up.
@@marcellemay7721 They aren't super expensive. but you do need to make sure you understand the difference between start and run caps. I bought a quite a few extra run caps in both 100uf and 50uf. That gave me more than enough range to balance the power.
enjoyed...honestly electrical issues make me sweat...but learned a lot from the video....I hit the sub button to watch more of your videos
They are in that category of not really hard, but not forgiving either.
hi I see a funny mask I had never noticed before the figure mask on the left hand wall top of the frame. Phase converters. Nice to see this option when you do not have 3 phase power which put us into the poor house and a half but once done we are happy went with 400 AMP can upgrade to 600 AMP later they said. Wow that is a lot cap cans i one devise with two in it might show it one day it shocked us one. Love that band saw brand it is what I ran as a child machinist in training. You did great work, in the end your build looks GREAT.
He's a star wars junkie, its all good , I like Stagate SG1.
Excellent explanation,please what is sizes of various capacitors you used,I will be grateful if you send a diagram for this project,hopefully to see your reply sir
The start capacitors have to be sized to the motor you are running. The run capacitors have to be sized to balance the load. I purchased a mix of 50 and 30 Mfd run caps and then added them until the voltage was just slightly over (8%) the target of 240v.
I don't have a drawing of this specific rotary phase converter, but in my description are links to the one's I used to plan mine out.
Arson smith, are you saying that you fired up a 30 HP motor on just 50 amps? I have folks on PM saying I will be making a light show throughout the neighborhood if I try to cap start my 50 hp. Yeah right I have my own power pole and transformer from POCO. I was about to buy a ready made cabinet and they scared me out of it. I decided to go pony motor which will be far more complex. But now after seeing what you are doing I am left scratching my head. I have 200 amps( more like for an inductive load only the power company says)
I've been running the 30hp now on a 100amp breaker for a couple of years. originally it was on a 50amp breaker and it would pop it every once in a while. as a quick update I swapped in a 70amp and was able to run it for a while, although the wiring was way to small. I have since updated everything to a 200amp sub panel and a 100amp breaker to feed all shop 3 phase.
@@TheArsonsmith4242 so basically you saying that my having 160 amps to the shop ( maybe 200 for inductive loads) and a 50 HP Idler I should go ahead with the cap start without any worries and put this thread behind me.
www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/50-hp-rotary-pony-not-pony-389477/
@@joeshmoe5935 I can't give a professional opinion on it as I am not an electrical engineer. All I can say is that it worked for me at the numbers I posted above. (not without problems at the low numbers) your millage may vary.
@@TheArsonsmith4242 seller didn't even want to guarantee me under 150 amp draw, that's why I started thinking only way to go is pony motor. At 70 amps, did you have trouble?
@@joeshmoe5935 At 70amps it would occasionally pop the breaker. American Rotary has stats for all their converters and what is needed for them if you want a more official source. www.americanrotary.com/pdfviewer/?pdf=3108 Looks like their ADX-50 recommends a 150Amp breaker.
U can do away with that cap. relay and put in a potential relay it will turn the start cap. Off automatically without an momentary switch
Yeah, I even bought one and have it sitting in my todo box. I'm stuck in that limbo of it works good enough to not tear it all apart to add in the new relay.
Are all your run capacitors the 50 micro farad ones you have in your Amazon link? I was looking at just putting in a bulk order for some 100 micro farad run caps for my 30 hp build and a couple smaller ones to fine tune.
I had 50 and 30 Mfd caps. I was able to balance the voltage to within tolerance using just the 50s and skipped the 30s. you can mix and match. 100mfd may not be fine grained enough for you to balance the voltage.
@@TheArsonsmith4242 thank you
Thanks for sharing such fantastic info and well delivered too! Great Job :) I have an old shop-bought one I got 14+ years ago and it won't run my 3 phase inverter welder but will run my panel saw? I suspect it has an issue with the idler motor as it seems to start and run OK with correct voltage, but when I check the output for amps at idle I get minimal values (e.g. 0.78 amps?). I am just wondering what output amps you are getting on the output side when idling? thanks again!
At idle with no load the amp meters read 0 on all 3 phases. It isn't until I put a load on it that they go up. Running the bad say each leg gets 2-3 amps. Been focusing on getting a new power drop to the shop so I haven't run anything other than the band saw on it.
@@TheArsonsmith4242 Great thanks for your reply! So maybe I should load it up and measure the out when loaded. Thanks for the info...Keep the vids coming :)
Would it help to put a small motor (single phase) with a belt going to the 3 phase motor to spin it in the correct direction?
Some RPCs do have a pony motor to kick start them. So far it hasn't been much of a problem.
Cool project. Did you consider a time delay relay instead of the momentary switching for starting? Have you figured anyway to get around the reversing issue?
I actually got a voltage sensing relay and some other parts that as soon as my home remodel is done I'll be working on a rebuild of it with lessons learned.
@@TheArsonsmith4242 Can you please do a video on your modifications, and also a little more detail around process of balancing the run caps please? Maybe a link?
how much can a 10A main fuese handle ?? it can just pull a toaster 2000W.. milling machines use a lot of power. we have problems with our maho 400.T cnc mill we have 3 phases with 16 A fuses on
10 amps times 220 volts divided by 750watts = ~hp load or almost 3hp.
I'd be careful on a 10A breaker/fuse, especially converging to 3 phase as you're going to need a bit more draw.
What was the sizes of run capacitors in total?
They sell these switches on Amazon, ebay, and I assume Craig's list.
Sir for 20hp? I have 220volts supply I want to run 20hp 3phase 380 volts. What capacitor I need? Tnx sir
It will differ for every motor. You'll need to find an estimate starting point then tune with a multimeter once you get everything close.
The tuning process is just a matter of start everything up and check the voltage. Shut it down and add or remove a capacitor and do it again until you find the combination that gives you good balance +-10% or so.
@@TheArsonsmith4242 tnx master
Can you tell me the details on the contactors, like the manufacturer and model number? Thanks.
Right now everythings sealed up so I cant really get to them and I didn't document it. basically you just need contractors that support the amperage you need.
This ebay search might be a good starting point: www.ebay.com/sch/i.html?_from=R40&_trksid=p2507978.m570.l1313.TR2.TRC0.A0.H0.X60+amp+contactor.TRS0&_nkw=60+amp+contactor&_sacat=0
You have your L1 L2 and L3 for your induction to start your motor... If you change your L2 and L3 around, won't it change your polarity to your motor so your motor will start?
It's being started from single phase. Remember you have to measure between to Legs to measure a phase so the two lines I have going in only count as 1 phase between L1-L2. Adding one more wire gives me the ability to measure between 3 sets of wires L1-L2, L1-L3 and L2-L3 giving me the 3 phases.
Did you get around to adding a meter to the input side to see how many amps you were pulling from mains? If so I'm curious how many amps?
I have one, but completely forgot about actually adding it. May be purposefully forgot I'm not sure. I'll see about adding it this weekend.
@@TheArsonsmith4242 hey, thanks for replying. I'm most curious how many amps the rpc is pulling.
@@johnnyfetzner6795 I am too, also a bit nervous, not sure I really want to know.
lol.
well, you guilted me into it. Idle it draws about 13amps. loaded up with the CNC spindle running it goes to about 20amps, same with the bandsaw. Both draw about 5-6 amps across each of the 3 phase lines. That's all the testing I've done so far.
Awesome!! I expected a much higher draw. Bonus question if I may what is the tag max amps on your idler motor?
so is the RPC motor a single phase or 3 phase?
It's a 3 phase motor. for an RPC you use single phase to kick start it and get it spinning, The other 2 windings in the 3 phase motor work like a generator to generate the other two phases. The capacitor banks are then used to keep the voltages even.
great video! i was wondering, when you connect your 3 voltmeters, do you connect them phase to phase or phase to neutral?
it's phase to phase, no common in 3phase power. From my understanding when you see 208V 3 phase power that is typically so you can also run a common wire and connect to one phase to common and get 110v power, but I have no experience with this.
TheArsonsmith4242
Thanks!
Oh by the way, I am subscriber 333.
Over 100 new subs in like 4 days. I need to get some new videos out.
@@TheArsonsmith4242 Congratulations!! Good content brings new subscribers.
Sir, can you build a panel like this for me
What kind of wire (awg and voltage) do you use to connect the capacitor?
Thanks
I Purchased the DROK 0.39 Inches LED 2in1 Multimeter AC 500V 200A Voltmeter Ammeter, AC Volts Meter Panel Ammeter Gauge with Current Transformer, 2-Wires Digital Ammeter Volts Meter Tester.
Like the one you have from Amazon.
I have a Rotary three phase converter.
Can you tell me how to wire it to three phase which wire does the red and black wire connect to since it is three phase.
Please help
Sent from my iPhone
1Attached Images
You want to measure between the 3 phase wires. You will need 3 of the DROKs to measure all 3 phases and display the amps drawn on each of the 3 wires. Follow the setup similar to the imagelinked below except replace the blue and yellow with each set of your colored wires. if you have red/blue/black then:
(red)-blue
(blue)-black
(black)-red
with the amp ring around the color in parenthesis.
images-na.ssl-images-amazon.com/images/I/61jdhqTrmgL._AC_SL1500_.jpg
I'm looking at a Haas VF3ss which has a 30HP direct drive motor and the power requirement is 70 amps @ 220 volts 3 phase. I have a 200 amp single phase service. Is it feasable to build a 3 phase rotary converter for this in my scituation or is this just to much to ask?
you can get an idea here www.americanrotary.com/products/view/ad-digital-smart-series/?attribute_model=AD-60
man, you should be teaching
Thank you for the vote of confidence.
So, you have VFD's on everything, which are more efficient at converting single phase to 3 phase, cheap, and gives you speed control, and yet you're replacing them with a rotary phase converter, which is less efficient, heavy, expensive, has voltage imbalance in the phases, and gives you no control over the speed? Ok, I guess if you want to...
Nope, I have VFDs on two motors and have 5 more motors that would need VFDs. VFDs are a bit expensive with one 2HP VFD costing almost as much as what I paid for a whole shop 30HP RFC and VFDs are only good for a single motor. They also produce a high pitched wine in the motors that can be reduced with tuning but changes over time. If you have a small number of motors to power (1-3) then yes stick VFDs on them and be done. If you have a shop full of equipment and may want to swap in and out more equipment over time then VFDs quickly get a bit expensive.
FVD ,,,no problem,,,,,, but! for the power you need gonna cost a lot $$$$$$$$$$$ because the bigger the VFD the more $$$$$$$
Yep, running it for 24 hours straight ends up costing about $15, although that is also with a CnC machine running long jobs as well.
Did you ever find out why your phase converter wants to run in reverse and blow your shop breakers?
Sort of and not really. I have it now where I can kick it in the right direction then hit the start. Been starting it that way every for almost year now and am just used to it.
Max current per phase ???
Without going out and doublechecking the numbers it calculates to about 25-35amps per leg.
@@TheArsonsmith4242 :v
that's very bad....different voltages and different amperes for each phase. you will burn the motors.
They are insured to be in the correct tolerances. Under load they balance out as they are supposed to.
Wow. Complicated!
You went through the bit about the second switch so fast that you lost me?
The two contactor switches or the external switches? both have to do with engaging the startup capacitors only for the starting of the motor then switching to the running capacitors once going. Most single phase motors will have a centrifugal switch in them that once they get to speed it'll disengage the start capacitor.
Nice. Feel free to embed your videos on our homemade tools forum; looks like you're one of us :-)
I need to build a 3 phase converter for welding shop. Three welders, air compressor, mill, & band saw. Can you suggest where I can learn more about the requirements & where to purchase components ? I have access to 25hp & 50hp motors. Not sure of my input power, but I'll have it boosted if necessary. Any advice/recommendations are appreciated. Thanks for your videos.
I got most of my info from this video: czcams.com/video/u229h7NcMxk/video.html he does an excelent job going over it. He also links to this document which I also used: www.practicalmachinist.com/FitchWConverter.pdf
@@TheArsonsmith4242 Great! Thank you, I'll check them out.
One more question. From your experience, can I operate a welder(s) on a 3-phase converter? Have found no videos/info on the subject.
@@gregcombscustomcultipacker5785 I haven't ran a welder on it, but even with the limited knowledge I have of them I don't see why not. A rotary phase converter makes a pure 3 phase sine wave just like you would get from the power company. Pay particular attention to the balancing portion and go about 150% of the power you need on the idler motor.
Here are some links to some of the supplies that I used in this build:
www.amazon.com/gp/product/B01M27KVPM/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
www.amazon.com/gp/product/B01AHWXOSA/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1
www.amazon.com/gp/product/B0773WGHNY/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
www.amazon.com/gp/product/B071GKH9HX/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
Man you are not working with single phase AC supply. Technically you started with 2 phase 3 wire supply with 110V approx in each phase. With this video I came to know that in USA this type of domestic electric supply is available. In India we have either 230 V single phase supply with two wires. Or 415V 3 phase 3 wire or 4 wire supply. Thanks
You can't have 2 phases with only 2 wires as you need to measure each phase across a different set of wires. To have 2 phase you still need 3 wires, 2 separate supply and a common. With only two wires (+ ground) you can only measure a single load across those two wires so only single phase. with 3 phase, all 3 wires are supply and you can measure 3 ways across each of them.
@@TheArsonsmith4242 no no no. U misunderstood. In India we have a very different supply system than yours in US. Our single phase means a phase wire or live wire with 230V, 50 hz AC and a neutral wire. We don't have 110V - 0 - 110V type supply. Thanks for replying.
@@souvikdey9178 yes, our 220-240v system is just often confused for being 2 phase.
@@TheArsonsmith4242 dear sir, in South Africa we have the same 'problem'. 3 wires. One ground, one neutral (no voltage) and one live(240v). These RPCs really sparked (pardon the pun) real interest for a 3 phase solution for my workshop, until I read Souvik Dey's comment. Feels like my kite is shot out of the air. In my lame man's terms (electricity is not my thing, so I lack terminology) if I try to build a RPC like yours, I can only feed one phase on the 3 phase motor/generator. Would you be able to provide insight how to "revive" the 2 remaining ghost phases? Thank you in advance!
@@TheoTHERON_SA you can still start a motor with single phase 240v and neutral.
czcams.com/video/jMmUoZh3Hq4/video.html
Hello I am interested in Rotary Phase Converters. I would want to build. I have a 5 HP 240V motor. I connected on 240v single phase L1 and L2 to Switch to T1 and T2 5HP 240V But the motor did not run. I think I need to add capacitors for the starter motor. Then I connected T1, T2 and T3 to Crane's 208v 3HP 3 phase. Can you help me how to build the switch and capacitors. maybe I could get a display? Please send me an email Thanks.
While I never really did a diagram, many of the links in the description have much more details and diagrams. the only difference in mine and yours would be the sizing. You'll always need a bigger HP rotary phase converter than the motor you are trying to run. I have a small 1.5hp rotary that could start a completely unloaded 2hp motor but even the slightest load on the same motor and it wouldn't start.
The 240V 1PH systems that superimpose a third leg are GROSSLY inefficient because the 240 are still 180 degrees out of phase from one another, with the third leg being somewhere between the other two. One leg will always draw more current than the other two, which is evidence of imbalance. It's FAR better to just buy a VFD...unless the motor usage is only occasionally, and so not economical. However, in the long run, just buy a VFD.
This is a common misconception. Due to the spinning of the 3phase induction motor makes sure the 3 individual sine waves are 120° apart as is evident on an oscope. VFDs are great if you're running a single motor but a system to run an entire shop 20-30hp worth is prohibitively expensive. I use a mixture of both in my shop where needed.
@@TheArsonsmith4242 We used spinning induction motors as well at Boeing when I worked there, but that was only to generate three phase at a specific frequency for a specialty machine. The worst of all the rig-ups I've seen is capacitors to induce a thir leg between the two 240V legs that are 180 degrees out from each other. That was out in a field for a 75HP irrigation pump. One leg always ran hotter, and so the motor was always imbalanced, this putting more electrical stresses on one coil in relation to all the others.
@@musicinspire1745 That is an interesting setup. Here we don't have two 240v legs that are 180 degrees out of phase, we have a single phase 240v that oscillates between +120v and -120v. This is due to the way residential housing in the US taps the power transformer on the poll to make 120v circuits as well as 240v. Another common misconception is to think of that as two phases but I assure you it is a single phase since a power phase is measured between legs not the legs themselves. To have a 2 phase system you would still need at least 3 legs, while measuring between one set of them would measure no voltage, otherwise it would be a 3 phase system.
That’s total crap. Says building, not refurbishing. Hate false video titles!
Lol
Ip
Why do Yanks talk a lot of waffle untill they get to the point.
Gives me something to do while I'm trying to come up with a point.
I like to start with an Idea then draw up a plan then spec the needed parts then build. I'm at the capacitor part, Now i have to stop watching. too painful. Please Do not apply for an electricians job. thanks.
Make a better video about it, I dare ya.
I don't like this idea at all, it's not safe, the phases aren't balanced, and the starting arrangement is so poor, this could easily cause a fire. With 40 years of experience under my belt, I would condemn this idea out of hand. The only way to do this properly is with a solid state inverter, or a synchonous motor and three phase alternator. NB don't run cables all over the floor.
Thank you.
What was the sizes of run capacitors in total?