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gazza2009au
17th Oct 2016, 09:12 AM
Hey Guys, is it as easy as running a 3 phase motor as a generator powered by a single phase motor to run 3 phase power out in the shed?

are there any complications? i have been looking online at making one but thought i should ask first

looking to power 3 phase lathes and older mode 3 phase welders and tools

https://www.youtube.com/watch?v=FeH580M336c

jhovel
17th Oct 2016, 12:52 PM
Sadly not as easy as that..... 3-phase alternators have a field winding which is controlled, motors have just a soft iron core.
As you can imagine, if it was as easy as that, eveyone would be doing it.
The solution is either a rotary phase converter (expensive, noisy and inefficient) or a VFD (relatively cheap, very efficient and lots of benefits like gentle acceleration, variable speed, active braking and motor protection).

gazza2009au
17th Oct 2016, 01:30 PM
I'm not sure what u mean mate? I'm going by this link http://www.redrok.com/cimtext.pdf everyone is doing it on Youtube just i have not seen any MIG welders using it only ARC

Vernonv
17th Oct 2016, 01:50 PM
I didn't bother to read all of that doc, but I suspect that it may just be using the 3 phase motor as a phase converter, being helped along by a single phase motor ... but I could be wrong.

Phase converters need not be expensive or noisy, but I'm not sure about how inefficient they are.
I have 5x3 phase machines and having a VFD for each one would cost a small fortune. My phase converter cost me about $150 (used a lot of scrounged parts).

Vernonv
17th Oct 2016, 01:53 PM
PS : You also can run into issues with VFD's if the machine has multiple 3 phase motors in it.

gazza2009au
17th Oct 2016, 02:21 PM
I didn't bother to read all of that doc, but I suspect that it may just be using the 3 phase motor as a phase converter, being helped along by a single phase motor ... but I could be wrong.

Phase converters need not be expensive or noisy, but I'm not sure about how inefficient they are.
I have 5x3 phase machines and having a VFD for each one would cost a small fortune. My phase converter cost me about $150 (used a lot of scrounged parts).

Vern do u have any pictures of a phase converter?

I'm always on a tight budget for tooling so i see all these great older model machines going for next to nothing because they are 3 phase, 3 phase is not available to me its a shame i would have had it installed years ago and the price of the older machinery to the Chinese tools these days is about equal but i think the older used gear is far superior in quality like the older CIGWeld or WIA welders go for nothing these days

i will have to do some research on the phase converter, so far i have only came across two types of generators one was as mentioned a small electric 240v motor powering a 3 phase induction motor to create 3 phase power (i was looking to make around a 7.5-10kw model) and another one was using just a single 3 phase motor on its own with capacitors (i'm unsure how this one works)

malb
17th Oct 2016, 05:22 PM
Joe's information is correct, it's not as easy as that. I read your PDF link and yes they make it sound easy BUT:

They are dealing with 60Hz 110V mains, not our 50Hz 230V mains. (Concepts should hold but values etc would change)
The values of the capacitors used vary with load, and aren't specified at at any power level, it always has been a suck and see style arrangement match caps to the load.
A normal alternator has two groups of windings, one fixed and one rotating. A controlled current passes through one winding and the shaft is rotated at a fixed speed to generate the output frequency required. (50Hz in our case). The controlled current is used to control the output voltage. Three phase units being powered by the device require reasonably accurate control of frequency and voltage, although some latitude is permissible if you do not need accurate speed and power from the unit being driven.
As described in the article you linked to, the output voltage is being controlled by the drive RPM of the alternator, which means that the output frequency will vary with the output voltage, not good for operating motors or medium sized transformers in old style welders etc, as either the machine speed or transformer output voltages and frequencies become uncontrolled, or you risk operating the unit at voltages exceeding their input specifications and risk premature failure. There does not seem to be any mention of what they are trying to drive in the article, other than using a lightbulb as a test device. The system as outlined is viable if you want to drive something like strings of bulbs, or heating elements, which are voltage sensitive but not frequency sensitive.

A rotary phase converter uses the 3 phase motor with one phase winding connected to mains power, and capacitors and the two remaining phase windings being used to synthesize the other two phases, but again the capacitor values need to match the load applied, and vary significantly. There is a computerized unit sometimes advertised on ebay that can switch various capacitors in and out of circuit to try and match the capacitors to the load, avoiding the need for the operator to monitor and manually switch capacitors to match the load, but it isn't cheap.

Regardless, if you want to be able to "make" 10KW of three phase power, you need at least 10KW of single phase to start with, more likely 13-15KW when you take mismatching and inefficiency into account. At 230V, thats in the order of 60 to 65A. Oh, and you would only be generating a nominal230V phase to phase so all of the units you drive this way would need to be able to be configurable for delta connection, just as if you used a VFD unit to generate the three phases.

gazza2009au
17th Oct 2016, 08:35 PM
Joe's information is correct, it's not as easy as that. I read your PDF link and yes they make it sound easy BUT:

They are dealing with 60Hz 110V mains, not our 50Hz 230V mains. (Concepts should hold but values etc would change)
The values of the capacitors used vary with load, and aren't specified at at any power level, it always has been a suck and see style arrangement match caps to the load.
A normal alternator has two groups of windings, one fixed and one rotating. A controlled current passes through one winding and the shaft is rotated at a fixed speed to generate the output frequency required. (50Hz in our case). The controlled current is used to control the output voltage. Three phase units being powered by the device require reasonably accurate control of frequency and voltage, although some latitude is permissible if you do not need accurate speed and power from the unit being driven.
As described in the article you linked to, the output voltage is being controlled by the drive RPM of the alternator, which means that the output frequency will vary with the output voltage, not good for operating motors or medium sized transformers in old style welders etc, as either the machine speed or transformer output voltages and frequencies become uncontrolled, or you risk operating the unit at voltages exceeding their input specifications and risk premature failure. There does not seem to be any mention of what they are trying to drive in the article, other than using a lightbulb as a test device. The system as outlined is viable if you want to drive something like strings of bulbs, or heating elements, which are voltage sensitive but not frequency sensitive.

A rotary phase converter uses the 3 phase motor with one phase winding connected to mains power, and capacitors and the two remaining phase windings being used to synthesize the other two phases, but again the capacitor values need to match the load applied, and vary significantly. There is a computerized unit sometimes advertised on ebay that can switch various capacitors in and out of circuit to try and match the capacitors to the load, avoiding the need for the operator to monitor and manually switch capacitors to match the load, but it isn't cheap.

Regardless, if you want to be able to "make" 10KW of three phase power, you need at least 10KW of single phase to start with, more likely 13-15KW when you take mismatching and inefficiency into account. At 230V, thats in the order of 60 to 65A. Oh, and you would only be generating a nominal230V phase to phase so all of the units you drive this way would need to be able to be configurable for delta connection, just as if you used a VFD unit to generate the three phases.

Thanks for the post Malb :) Do u know if there is a DIY 3 phase voltage regulator i can build or possibly buy one? i will do some searching now

i had rushed out and bought the only decent HP motor i could find than came home and seen your reply :doh: but none the less i will still go a head with plan A and build a 3 phase generator i will sort thru the problems if possible

the motor is a 13.7amp, 415v, 3 phase motor i think it works out at 10hp i can purchase one of those Honda knock off motors from Ebay to run this motor, only down side i think will be noise because it requires 2900RPM running speed but if i can pull this off and have a stable voltage supply it should work ok

one other weird thing i noticed is there are two cut wires that go into the electrical box, one wire is 1 phase the second is 3 phase the motor states 3 phase on the builders plate so why would 1 phase be wired up?

rcaffin
17th Oct 2016, 09:42 PM
Why not get genuine 3-phase power brought into your house? Excuse is 'I have 3-phase machinery'.

Cheers
Roger

jhovel
17th Oct 2016, 11:59 PM
The single phase cable is probably to have a 415V worklight or a transformer connected and the 3-phase cable to run the motor.
Note that your motor is a DELTA wound motor for 415V 3-phase. NOT 'star' wound as in the linked pdf file. You will need to do some more reading about capacitor selections to try what you want to do in plan B (rotary converter).
But I would suggest that you just try plan A first and report how you go. Nothing is learnt by not trying things others have dismissed :)
You can't do much harm and you will only waste a litte time (if you already have a suitable drive motor, or buy one you can use for something else down the track). You never know, all those Youtube types might be right after all :) (and all the electrical engineers wrong). :)
The only thing you shouldn't do here is NOT reporting successes or failures. We all support each other and are glad to learn from each other!:2tsup:

rcaffin
18th Oct 2016, 07:14 AM
if you want to be able to "make" 10KW of three phase power, you need at least 10KW of single phase to start with, more likely 13-15KW when you take mismatching and inefficiency into account. At 230V, thats in the order of 60 to 65A.

Good luck trying to pull that out of a domestic single phase supply. I can see fun and games with the main switch board fuses for a start. And then with the fire brigade, electricity supplier inspector, and your insurance company. You may invalidate your insurance policy along the way.

Comment: this is NOT a game for amateurs.

Cheers
Roger

Vernonv
18th Oct 2016, 08:29 AM
Vern do u have any pictures of a phase converter?There are plenty of examples on the web ... or did you specifically want a pic of mine?

BTW you can also convert some of the older transformer based mig welders from 3 phase to single phase ... I've got an old UniMIG 350 that I converted. I thought I had posted the conversion here, but I can't seem to find it now ... I'll keep looking.

EDIT : Here it is (http://metalworkforums.com/f160/t192889-converting-3-phase-welder-single-phase)

BobL
18th Oct 2016, 10:43 AM
There are plenty of examples on the web ... or did you specifically want a pic of mine?

BTW you can also convert some of the older transformer based mig welders from 3 phase to single phase ... I've got an old UniMIG 350 that I converted. I thought I had posted the conversion here, but I can't seem to find it now ... I'll keep looking.

EDIT : Here it is (http://metalworkforums.com/f160/t192889-converting-3-phase-welder-single-phase)

We've had "donations" of several of these converted welders at the mens shed.
A small one had a 15A plug and drawing about 12A max was OK on a 15A circuit.
A much bigger one came in with a "somewhat scorched" 10A plug and was trying to draw over 20A!

gazza2009au
18th Oct 2016, 12:59 PM
The single phase cable is probably to have a 415V worklight or a transformer connected and the 3-phase cable to run the motor.
Note that your motor is a DELTA wound motor for 415V 3-phase. NOT 'star' wound as in the linked pdf file. You will need to do some more reading about capacitor selections to try what you want to do in plan B (rotary converter).
But I would suggest that you just try plan A first and report how you go. Nothing is learnt by not trying things others have dismissed :)
You can't do much harm and you will only waste a litte time (if you already have a suitable drive motor, or buy one you can use for something else down the track). You never know, all those Youtube types might be right after all :) (and all the electrical engineers wrong). :)
The only thing you shouldn't do here is NOT reporting successes or failures. We all support each other and are glad to learn from each other!:2tsup:

:U Awesome mate, in that link i posted they said if i over loaded the generator it would just stop working but I'm not sure about the capacitors and if i did go over voltage and by how much and what max voltage capacitors i use if it would effect them... so some reading needed

I'm very keen to try it

gazza2009au
18th Oct 2016, 01:02 PM
There are plenty of examples on the web ... or did you specifically want a pic of mine?

BTW you can also convert some of the older transformer based mig welders from 3 phase to single phase ... I've got an old UniMIG 350 that I converted. I thought I had posted the conversion here, but I can't seem to find it now ... I'll keep looking.

EDIT : Here it is (http://metalworkforums.com/f160/t192889-converting-3-phase-welder-single-phase)

Sorry Vern miss read what u said i thought u had turned single phase into 3 phase thru a converter

Vernonv
18th Oct 2016, 01:49 PM
We've had "donations" of several of these converted welders at the mens shed.
A small one had a 15A plug and drawing about 12A max was OK on a 15A circuit.
A much bigger one came in with a "somewhat scorched" 10A plug and was trying to draw over 20A!Sure, if you are not careful or are unaware.

I bought the welder for around $100 (completed with remote feeder) and spent maybe $20 on converting it. I have welded everything from 0.9mm sheet through to 25mm plate. It's on a 15A circuit and I keep an eye on cable/plug temps when it's running anywhere near full noise.

Best $120 I ever spent on a welder. :D

gazza2009au
18th Oct 2016, 05:28 PM
Looks like these capacitors will be the hardest parts to find of the build, Does anyone know of US friendly shops that ship to AUS? i found oil capacitors in the US for $5 but over here they are $50-$100 each which is crazy

looking for 24uf 480VAC oil filled

can't seem to find them anywhere in OZ i wonder why? 3 phase is pretty common here on the commercial scale and electric motors are everywhere so strange i cannot find them

malb
18th Oct 2016, 06:25 PM
Thanks for the post Malb :) Do u know if there is a DIY 3 phase voltage regulator i can build or possibly buy one? i will do some searching now



Short answer is no, because there is no where that it can be included in a driven induction motor to have regulating effect.

Induction motors (single or three phase) like the one you bought only have one set of true 'run' windings per phase, and the single phase have an additional 'start' winding to get them turning then it is switched out of circuit. The armature (rotating part on shaft) consists of a metal core on the shaft with a handfull of copper or ali rods parallel to the shaft set into the core, and all joined at each end.

An alternator armature has a winding wound concentric to the shaft, and housed in a different core structure. The armature is driven at an appropriate speed to control the output frequency, and the DC current flowing through the concentric winding is controlled by the regulator to set the output voltage.

If you ever get a chance, look at some of the older generating plants in museums, preservation societies etc. They generally have the engine, alternator and exciter arranged in that order. The exciter is a DC generator that creates a current that is fed through the armature winding of the alternator to 'excite' the alternator, or create a magnetic field at the armature. When this field is forced to rotate by the engine, the magnetic field at the armature rotates and the constant change in magnetic field induces voltage in the main or stator windings, which is then distributed to operate other loads.



EDIT: Just found the bit enquiring about capacitors etc. Not commonly found here because there is not a huge DIY 3phase experimenter population here. Capacitors are not required when using the motor as a motor, so there are not a batch of capacitors installed with the motor normally.
Beware of buying 480VAC caps for that application with a 415V target as the voltage rating is rather close. If when these things (capacitors) get overvoltage applied, the results can be somewhat loud and smelly. I would be looking at 600VAC min, and they will be rarer/dearer still.

gazza2009au
18th Oct 2016, 07:47 PM
Malb i hear you mate, i just read a little information about capacitors and voltages, it said along the lines the capacitors voltage is the max voltage it can take, this may have been why the person in the link said to use 480v capacitors maybe in a way of limiting the generators output of voltage so it only destroys the capacitors rather than what the generator is powering? (welder)

also read about uF which from my understanding is like a wave length if u go over or under it can put to much load on either the motor or capacitors

so now im looking for 500v and 24uF or 25uF i will up my search to include up to 600v capacitors

their are online calculators for motor RPM's and pulley sizes and all other sorts of information i should be able to get close to the required generator RPM if i use a sufficient drive motor, i am trying to find s 2800-2900RPM drive motor so i can run two 100mm pulleys as the pulley on my generator is 100mm and requires 2900RPM

forgot to mention before when i removed the cover on the generator motor it showed both wiring config's so it should be simple to convert :2tsup:

i found a petrol Honda copy motor on the internet very cheap i thought about using it to power this beast of a motor but than thought it may be a bugger to move as the electric 3 phase motor weighs along 71kg so if i go electric drive motor i can just install it in the shed corner and leave it there, no fumes and no carbon monoxide to worry about while working

.RC.
18th Oct 2016, 07:56 PM
Whilst I do not think this is going to be a successful project and you would be better off building a rotary phase converter.

The capacitors you require are called CBB65A type. Most commonly in 450V, however there are some 500V ones available eg: AC 500V 20uF Air Conditioner Motor Run Capacitor CBB65A | eBay (http://www.ebay.com.au/itm/AC-500V-20uF-Air-Conditioner-Motor-Run-Capacitor-CBB65A-/391243017775)

Phase Change Converters based outside Melbourne use 600V versions in their phase converters. Whether they will sell you any is another question. They have sold them to me, but I have one of their phase converters and it was for them. They are around $30 each.

You will probably have other issues like switchgear to sort out as well. You are not going to build a 7.5kw device without some serious input amperage. I have an 8kw phase converter and it runs off a 50 amp breaker however when I start the lathes 7.5hp motor, it dims the lights in the house and the line voltage drops. You do not actually say what you want to run in any detail so offering advice is not very easy. A lot of us have been where you are now and how we went about things might have been different if we knew back then what we know now.

gazza2009au
18th Oct 2016, 09:05 PM
Whilst I do not think this is going to be a successful project and you would be better off building a rotary phase converter.

The capacitors you require are called CBB65A type. Most commonly in 450V, however there are some 500V ones available eg: AC 500V 20uF Air Conditioner Motor Run Capacitor CBB65A | eBay (http://www.ebay.com.au/itm/AC-500V-20uF-Air-Conditioner-Motor-Run-Capacitor-CBB65A-/391243017775)

Phase Change Converters based outside Melbourne use 600V versions in their phase converters. Whether they will sell you any is another question. They have sold them to me, but I have one of their phase converters and it was for them. They are around $30 each.

You will probably have other issues like switchgear to sort out as well. You are not going to build a 7.5kw device without some serious input amperage. I have an 8kw phase converter and it runs off a 50 amp breaker however when I start the lathes 7.5hp motor, it dims the lights in the house and the line voltage drops. You do not actually say what you want to run in any detail so offering advice is not very easy. A lot of us have been where you are now and how we went about things might have been different if we knew back then what we know now.

Thanks RC, i found this link about RPC's seems simple to make and i am halfway there diy - How to Build a Rotary Phase Converter to Convert Single Phase to Three Phase (http://www.nojolt.com/how-to-build-a-rotary-phase-converter.shtml)


To make a simple rotary phase converter out of a 3 phase motor Connect 230 volt single phase power to the T1 and T2 supply terminals (or wires) of the motor that you are using as a converter.
Get it Spinning (with a rope wrapped around the motor shaft for example) to get it going - it won't start on its own.
Take 3 phase power off of the T1, T2, and T3 terminals to power your three phase shop equipment.




is it really this simple? :o

but look here i don't understand this


Add run capacitors - A phase converter will work just fine without run capacitors, but they will improve performance and efficiency to some degree. Run capacitors must be rated for continuous duty at high voltages (330-370 Volts) and are permanently connected between the T1-T3 and T2-T3 connections. Ideal voltage balance is difficult to achieve without some kind of dynamic adjustment, because different load states will require different configurations of run capacitors. But it really doesn't matter that much in most cases for motor loads. Just use about 12-16 microfarads per rated horsepower of the idler as a general rule.

if your running 3 phase 415v why would i need to use 330-370v or am i miss reading this and that site is talking about 3 phase 240v? which i have never heard of untill recently...

.RC.
18th Oct 2016, 09:16 PM
Aussie RPC project. (http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/aussie-rpc-project-187272/)

Zip Start R.P.C. (http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/zip-start-r-p-c-213679/)

gazza2009au
18th Oct 2016, 09:58 PM
Aussie RPC project. (http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/aussie-rpc-project-187272/)

Zip Start R.P.C. (http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/zip-start-r-p-c-213679/)

RC That is a great idea the zip start i have never seen anything like it on a piece of machinery haha

i have a question, i only plan on running 415v 3 phase so i don't need 480v and 240v 3 phase but from my understanding of reading those threads the idea is to keep the welder as a welder and multipal power output source am i correct or does the welder play a part in converting or maintaining the 415v 3 phase power?

jhovel
19th Oct 2016, 01:08 AM
Thanks RC, i found this link about RPC's seems simple to make and i am halfway there diy - How to Build a Rotary Phase Converter to Convert Single Phase to Three Phase (http://www.nojolt.com/how-to-build-a-rotary-phase-converter.shtml)



is it really this simple? :o

but look here i don't understand this

if your running 3 phase 415v why would i need to use 330-370v or am i miss reading this and that site is talking about 3 phase 240v? which i have never heard of untill recently...

That s a good little introductory article on rotary phase converters. BUT you have to read all of it! I think you missed the bit about star and delta wiring "....The motor that you are using as a generator (rotary phase converter) is called an idler, and needs to have a 20-30% higher horsepower rating than the largest equipment motor that you will be using, and needs to be rated for 220-240 volts."
The motor you have is NOT suitable, because it is a DELTA 415V motor. The rewiring information you seem to have found is to make it a STAR 586V motor. There is actually no such voltage in use. The reason your motor could be switched from Star start to Delta run is to reduce the current it draws on start-up. A direct on line start current of a 10Hp motor will be HUGE and the star-delta switching is done to keep that in check.

Friendly comment:
if there is anything in the articles you read - or our responses to your questions - that means you may well have missed a CRUCIAL concept. You MUST research and understand EVERYTHING in build instructions or you will risk you life! From your questions, it is clear that you don't know or understand a lot of electrical concepts and physics.
Please be careful! We would hate to loose you.
As a result, I'm also loathe to give you any advice - information yes! - but no more "how to's". I would not sleep at night if you got harmed or worse because you misunderstood something I write.
For example: lots of insulation is NOT rated for 500V or more, and some of the spikes you may well generate could be higher than that.
Please be careful.

gazza2009au
19th Oct 2016, 01:25 PM
That s a good little introductory article on rotary phase converters. BUT you have to read all of it! I think you missed the bit about star and delta wiring "....The motor that you are using as a generator (rotary phase converter) is called an idler, and needs to have a 20-30% higher horsepower rating than the largest equipment motor that you will be using, and needs to be rated for 220-240 volts."
The motor you have is NOT suitable, because it is a DELTA 415V motor. The rewiring information you seem to have found is to make it a STAR 586V motor. There is actually no such voltage in use. The reason your motor could be switched from Star start to Delta run is to reduce the current it draws on start-up. A direct on line start current of a 10Hp motor will be HUGE and the star-delta switching is done to keep that in check.

Friendly comment:
if there is anything in the articles you read - or our responses to your questions - that means you may well have missed a CRUCIAL concept. You MUST research and understand EVERYTHING in build instructions or you will risk you life! From your questions, it is clear that you don't know or understand a lot of electrical concepts and physics.
Please be careful! We would hate to loose you.
As a result, I'm also loathe to give you any advice - information yes! - but no more "how to's". I would not sleep at night if you got harmed or worse because you misunderstood something I write.
For example: lots of insulation is NOT rated for 500V or more, and some of the spikes you may well generate could be higher than that.
Please be careful.

I think i mentioned it came with instructions for DELTA or WYE mate its under the cover on a diagram

i know i am playing with big voltage here so i want to take precautions, i know the output can be up to 500-600v which is deadly and i know about the capacitors holding charge...

there wont be any tinkering with live wires while the motor is turning over or connected to 240v the only thing i need to do while the motor is running is to check the voltages with a multimeter for later adjustments of the capacitors sizes to get close to 415v across the three terminals

as for live power past the generator between the welding machine and converted motor i will use a RCD for 415v

, i also i read the whole link mate i just never mentioned the wiring config of the motor because i had seen it under the cover, i also read this link too

phaseconverter (http://www.waterfront-woods.com/Articles/phaseconverter.htm)

gazza2009au
19th Oct 2016, 01:27 PM
Here is the wire diagram

gazza2009au
19th Oct 2016, 04:25 PM
I sent out around 5 emails to AC electricians in my area found on Gumtree, one reply so far and the electrician is willing to look over my wiring once i finish building my generator, i think if i hire a electrician this is the better way to go about it and it should only cost $100-$150 (1 hour labour)

I'm going to try make the 2 motor conversion as in one of the links i have posted it said it was a more pure power source running the small start and run motor with the idler motor

I'm unsure if i want a stationary power source or adapt my generator to a furniture trolley so i am able to wheel it around my back yard along with the welder but in doing this that motor is very heavy so unsure yet

jhovel
19th Oct 2016, 10:32 PM
I think i mentioned it came with instructions for DELTA or WYE mate its under the cover on a diagram

I know, that's why I gave you the note that you motor is NOT suitable. As I said in detail, when you change it from delta to wye, it will become a 586V motor. That setting is for starting only.....
I don't believe you understand the implications of Star/wye and Delta configurations or the significance has escaped you....

gazza2009au
19th Oct 2016, 11:58 PM
OK I'm with u now, my motor is wye or delta but it is currently wired in delta for high voltage, i had a read back thru my links i have posted and it seems i should be focusing on a induction generator rather than a rotary phase converter which the induction generator was plan A

now in the link on page one the guy i assume its a guy is saying the generating motor must not go over its rated RPM due to the higher revving of the motor producing in excess of 415v as others have already mentioned in this thread

i think it may be trial and error with pulley choices and possibly some sort of drive motor speed controlling to to control the over all voltage of the generating motors RPM to sit around 415v it may be hard to control and keep close to 415v under load the person in that link did mention the voltage under load dropped

am i on the right level now?

the video below is what i am trying to do however i know this bloke must have had a few beers to ve over revving the generator taking the capacitors up to 90htz but this falls under controlling the drive motors speed to achieve the power voltage i require

https://www.youtube.com/watch?v=y-bPJ2SZp7o

gazza2009au
20th Oct 2016, 09:57 PM
I picked up a small drive motor yesterday to give me a idea on what size i would need, it came with the power cord cut completely off so i done some re-wiring had to pull half of the motor apart than put it all back together i than fired it up only to hear it hum so i think the reason the cord was cut because someone knew the capacitor was shot

i had connected up the induction motor with a drive belt to this small drive motor and with a bit of a push start this little drive motor spun up the large 10hp induction motor

the little drive motor is only rated to 1450RPM with using a pulley calculator taking in the sizes of pulleys i was turning over the 10hp induction motor at 1305RPM no where near its 2900RPM run speed

i than checked for AC voltage but only got 1 watt so i think the induction motor needs to be energized by 12volts

i will check it out further tomorrow, i have read it only takes 1 second to energize so we will see

gazza2009au
20th Oct 2016, 09:59 PM
forgot the pics

jhovel
21st Oct 2016, 01:04 AM
The 7.5V the guy in the video got at about50Hz is about what I expected.
Once the voltage got to 60V and the induction motor started, I couldn't be bothered continuing to watch.
Just for your information, Gazza, universal motors don't care about frequency at all. They will run on DC and any frequency AC. All they care about is voltage.
Not sure what the 1/3 kW motor is for. It will spin a 10Hp easily - until you find a way to get it to generate against a load.....

gazza2009au
21st Oct 2016, 07:15 PM
The 7.5V the guy in the video got at about50Hz is about what I expected.
Once the voltage got to 60V and the induction motor started, I couldn't be bothered continuing to watch.
Just for your information, Gazza, universal motors don't care about frequency at all. They will run on DC and any frequency AC. All they care about is voltage.
Not sure what the 1/3 motor is for. It will spin a 10Hp easily - until you find a way to get it to generate against a load.....

The .5hp motor was just a $20 purchase that gave me a starting point as i found all kinds of information some saying i will need a drive motor 6 times the size of the induction motor others were saying 1/3rd hp of the induction motor so it is varying heaps from the resources I'm finding

i just tried the motor again but i chose to run the induction motors belt on the 38mm shaft and using the .5hp drive motor it spun up a lot faster but still no power, i measured only 3.8v on two of the three way terminals and on the 3rd measured 3v

using a online pulley ratio calculator it said my induction motor should have been spinning at 3815RPM i find it had to believe that much RPM but it would have been over 2000RPM, motor is rated to 2900RPM

gazza2009au
23rd Oct 2016, 05:25 PM
Ok i get the advice now guys that the motor wont work as i thought it would so i bought this an old welder is it safe to say i can wire it up to use 240v power and it will transform this 240v into 415v? or am i miss reading something from the below link

Zip Start R.P.C. (http://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/zip-start-r-p-c-213679/)

the welder only cost $50 so i am not at a great loss if it doesn't work

Vernonv
23rd Oct 2016, 06:46 PM
is it safe to say i can wire it up to use 240v power and it will transform this 240v into 415v?Yep (415V single phase of course).

gazza2009au
23rd Oct 2016, 07:23 PM
Yep (415V single phase of course).

Ahh ok i think i get it now, so Jim is using the capacitors to create the 3rd leg of the 3 phase from the 415v single phase to power the induction motor than the 3 phase is tapped off the induction motor to be used for machinery?

rcaffin
23rd Oct 2016, 08:18 PM
As I see it, either this project dies or the proponent dies.
I am not going to be involved.

Cheers
Roger

gazza2009au
23rd Oct 2016, 08:31 PM
As I see it, either this project dies or the proponent dies.
I am not going to be involved.

Cheers
Roger
Best not to say anything than Roger because a post like this is just looking for a high five or a pat on the shoulder is it not?

if u can't say anything good than why say anything at all?

rcaffin
23rd Oct 2016, 08:40 PM
Not a case of 'saying anything good' so much as waving a small warning flag that there could be some hazards ahead. Meant helpfully.

Cheers
Roger

gazza2009au
23rd Oct 2016, 09:18 PM
Ok sorry Roger


Guys do u know of any of the older model industrial sized machines that will weld thin aluminium around 1.5-1.6mm?

i am coming across machines like this

Mig Welder 150 | Power Tools | Gumtree Australia Camden Area - Leppington | 1124006565 (http://www.gumtree.com.au/s-ad/leppington/power-tools/mig-welder-150/1124006565)

uni mig 161 mig welder with regulator,trolley leads no bottle | eBay (http://www.ebay.com.au/itm/252598162883?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT)

i have no idea as to what other machines are out there in 240v that can weld aluminium other than AC TIG but my job is way to big for TIG

rcaffin
23rd Oct 2016, 09:42 PM
TIG welding should be able to get up to 6 mm in aluminium IFF you can get the power out of the wall socket. TIG welder output of 200 A may be needed for this.

But that suggests that your 1.6 mm thick Al sheet should be easy with (the right) TIG. Hum?

Cheers
Roger

gazza2009au
23rd Oct 2016, 09:52 PM
TIG welding should be able to get up to 6 mm in aluminium IFF you can get the power out of the wall socket. TIG welder output of 200 A may be needed for this.

But that suggests that your 1.6 mm thick Al sheet should be easy with (the right) TIG. Hum?

Cheers
Roger
Yeah i'm welding a boat and it requires around 8 meters of bead so looking for a MIG for now that can weld the thinnest possible aluminium, it's hard trying to find a MIG that can do 1.5-1.6mm material without blowing holes this is the reason i was looking into 3 phase 415v because from what i have gathered from looking at the chart pictures online the bigger heavier machinery is friendly with very thin aluminium

I recently had a chinese 175A MIG with spool gun i welded a 1.6mm thickness sample successfully but than i tried to weld a job and absolutely destroyed it and it was at the lowest setting possible to weld aluminium

plus my neighbours wouldn't want to steal a huge older model welder as it wouldn't have any value to them

do u guys think old school welders will be ok to run on VFD? Variable Speed Drive VSD VFD 4 KW 415V 3 phase in 3 phase out | eBay (http://www.ebay.com.au/itm/Variable-Speed-Drive-VSD-VFD-4-KW-415V-3-phase-in-3-phase-out-/322300437122?hash=item4b0a9a6282:g:wpwAAOSwT6pVnfhf)

i understand some of those ebay VFD's do say they can't handle welders but i'm unsure if they meant new technology with all the high end electronics inside a welder

rcaffin
23rd Oct 2016, 10:02 PM
Go with TIG. It is meant for thin metal.

VFDs? Not a chance. Totally wrong.

Cheers
Roger

gazza2009au
23rd Oct 2016, 11:00 PM
While i was buying the old welder today i got offered this a AC powered HF box that went with my welder but i chose only to buy the welder, is this the HF box for welding aluminium on the AC arc welder? need confirmation before i go back to pick it up

rcaffin
24th Oct 2016, 07:02 AM
The HF box is probably worth having. It puts a 'high frequency' AC voltage on top of the normal welder voltage. This makes it easier to strike an arc and maintain the arc. In fact, using one means you should not have to 'scratch' the electrode on the job to start the arc. Smoother running too. For more info, Google.
Example: High-Frequency Start Box (http://www.casano.com/projects/hfstart/)

Cheers
Roger

gazza2009au
24th Oct 2016, 12:33 PM
Can someone please tell me if this is correct to wire it up as 240v?

rcaffin
24th Oct 2016, 02:02 PM
Assuming the black lines are where you intend to put the bridges, it looks right to me. There are two bridges available in the photo, so that's good.

Always a smart trick to test the thing out on a circuit with a magnetic breaker. They can open much faster than a fuse.

(I do hope those terminals are normally covered! I expect so.)

Cheers
Roger

gazza2009au
24th Oct 2016, 03:06 PM
Thanks Roger, Yeah the cover is off the welder

gazza2009au
24th Oct 2016, 05:44 PM
I just went back and seen the guy who sold me the welder and i purchased the TIG box and just plugged it in and it works :U

a vintage 230amp AC arc welder and AC high frequency TIG box both for $100 how can u beat that this is the cheapest aluminium welder i have ever purchased

old mate said he has another AC high frequency TIG box for $50 but i was out of cash so had to leave it

only one problem is the HF box zaps continously so could become irritating

i also thing i still need a MIG to weld my boat

dwyersm
4th Apr 2020, 04:38 PM
Hey Guys, is it as easy as running a 3 phase motor as a generator powered by a single phase motor to run 3 phase power out in the shed?

are there any complications? i have been looking online at making one but thought i should ask first

looking to power 3 phase lathes and older mode 3 phase welders and tools

https://www.youtube.com/watch?v=FeH580M336c

Get this book for around $20-$25 AU, Its excellent, explains 4 methods of getting 3 phase from single phase.
Three-phase Conversion by Graham R. Astbury
But you'll need a hefty 240 -415V step up transformer for most conversions.
I bought a 10 kva 3 phase 240-415V transformer from ebay some years ago.
I reconnected it for single phase, i.e the 3 coils in series, I step up from 240 to 415, then with some capacitors I run a 10kW 3 phase motor as my 3 phase converter. You'll also need a temporary starting capacitor on a timer or whatever to start the big motor. Then this capacitance drops out and you end up running on the run caps. Roughly 70uF per hp.
Put a typical load on the converter such as mill or lathe under load, or strike an arc on the welder and tune the caps FOR THIS PARTICULAR LOAD. The caps will need to be varied for different loads. You can make banks of two or three sets of caps for each load you decide to run, and connect them in and out as required. Watch out for arcing when you switch in and out. Tuning the caps is a balance between voltage and current, current balancing may be just a little bit more important, so you'll need a clamp meter to measure current. Current is heat, and heat is dangerous to cables and wiring.
I can individually run a 4kW compressor, 10hp lathe, 350 amp welder, yes a 350A welder! and my cylindrical grinders (with 3 motors each) . I only worry about blowing the primary fuse out on the pole. With the welder I use about 70A single phase, don’t turn the stove or oven on as you will most likely blow the primary fuse on the pole.
Theres a fellow in NZ who makes the capacitor switching boxes, I forget his name, its "Euro--something" , EuroTech perhaps. He's not cheap, not expensive either, but I ended up buying a box from him about 5 years ago, and its still working fine.
All I do now is switch on the converter and everything else is sweet.
Shane,
Brisbane