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View Full Version : 240v 15a in 415v 3phase out - options?



variant22
28th August 2012, 11:48 AM
I am looking into equipping my home workshop to run 415v 3 phase equipment (mainly a 2 speed 3hp Cold Saw). I have read through the threads on here about the conversion and I have not really found what I am looking for. I would ideally like to be able to avoid any "home wiring" of the high voltage lines and use a "plug and play" solution. Is there anything out there that will do this for a $500 figure or am I dreaming?

As a side note 415v is not available to my house. I know nothing about 415 volt 3 phase power except for the fact that I can get a two speed machine for my shop for roughly $1500 less than a 240v variable speed machine.

jack620
28th August 2012, 11:55 AM
How many 3 phase machines do expect to eventually end up with? If only a couple, I would think you are far better off using a 240V to 415V VFD on each machine. That gives you speed control on each machine plus a lot of other options like soft start, Emergency stop, etc. From what I've seen, $500 should get you 2 VFDs. That should get you started.

variant22
28th August 2012, 12:08 PM
How many 3 phase machines do expect to eventually end up with? If only a couple, I would think you are far better off using a 240V to 415V VFD on each machine. That gives you speed control on each machine plus a lot of other options like soft start, Emergency stop, etc. From what I've seen, $500 should get you 2 VFDs. That should get you started.

I really only have plans for a single 415v 3 phase machine in the short term. With regards to the VFD's it is my understanding I have to actually wire these into the machine itself? I can't say I fancy doing high-voltage wiring unless it is absolutely straight forward. Will the fact that the machine is 2 speed cause any issues?

Stustoys
28th August 2012, 12:57 PM
Hi,
Yes there is, though its more like $600
items in Drives Direct Inverters LTD store on eBay! (http://stores.ebay.co.uk/drivesdirectinvertersltd/_i.html?_fsub=5)
I'd think long and hard about going this route. It may well be cheaper to get the motor rewound* for 240V 3 phase and use a $120ish VSD
Are the two speeds done with switching or gearing?
Are you buying second hand or new?
Is this for production or a hobby?


415V 3phase is only "high-voltage" phase to phase. Its 240V phase to ground(not that 240V cant kill you)


Stuart

*assuming its some sort of series delta, parallel star(or there abouts) two speed motor

variant22
28th August 2012, 01:12 PM
Hi,
Yes there is.
Are the two speeds done with switching or gearing?
415V 3phase is only "high-voltage" phase to phase. Its 240V phase to ground(not that 240V cant kill you)

Stuart

I am not sure if it is done via gearing or switching. I would have thought switching, but I am not sure. I have sent Hafco an email to see how the two speeds are done. The saw is the Hafco CS315: S828 | CS-315D MetalMaster Cold Saw Includes Stand | machineryhouse.com.au (http://www.machineryhouse.com.au/S828)

They offer the same saw in 240v, but the issue is it is single speed. I need 22rpm for stainless and 44rpm for mild steel.

Stustoys
28th August 2012, 01:30 PM
Ok I was thinking gearing as using switching gives you large steps in speed, but I see now thats what you want. So I guess switching even though it looks like they used the pictures of the 240V machine for the 415V page.

You said 3hp so the $600 becomes $480, but I also forgot postage. Now you shouldn't be charged VAT, so that should save you some money. good luck with that (as he either doesnt understand or doesnt want to lol)

You've also got the coolant pump to think about. That seller has told me that its ok to switch the pump on the VSD with the main motor, other people disagree. I haven't tried it and while with a $120 VSD I'd be tempted to "give it a go", I'm not as tempted to try with the $600 one.

Stuart

variant22
28th August 2012, 02:10 PM
You said 3hp so the $600 becomes $480, but I also forgot postage. Now you shouldn't be charged VAT, so that should save you some money. good luck with that (as he either doesnt understand or doesnt want to lol)

Stuart

With shipping it is looking on paper like it wont be worth it. Shipping from the UK for anything that is remotely heavy tends to be cost prohibitive.

Any thoughts on the next best option aside from ditching the idea?

Stustoys
28th August 2012, 02:26 PM
They arent heavy. Postage on mine was $60 about 2 years ago.
Assuming its a two speed motor, I'd be talking to a motor winder about having it rewound for 240V 3phase.
If you arent using this for production, first up you could try running the motor as is on 240V 3phase and make do with about 1.2hp

Stuart

PDW
28th August 2012, 03:43 PM
With shipping it is looking on paper like it wont be worth it. Shipping from the UK for anything that is remotely heavy tends to be cost prohibitive.

Any thoughts on the next best option aside from ditching the idea?

Go talk to an electrician or your local supply authority about getting 3 phase from the street. Unless you're right off in the sticks somewhere there's a good chance it's an option.

Your location is listed as 'Australia' which is fundamentally useless for offering sensible advice. If you're *that* paranoid about giving away information, frankly I can't really be bothered offering any.

PDW

BobL
28th August 2012, 03:47 PM
Go talk to an electrician or your local supply authority about getting 3 phase from the street. Unless you're right off in the sticks somewhere there's a good chance it's an option.

I thought he already said it is not available to his house?

variant22
28th August 2012, 03:52 PM
They arent heavy. Postage on mine was $60 about 2 years ago.
Assuming its a two speed motor, I'd be talking to a motor winder about having it rewound for 240V 3phase.
If you arent using this for production, first up you could try running the motor as is on 240V 3phase and make do with about 1.2hp

Stuart

Thanks for the idea Stuart. I called the local Motor Rewinding company and they basically told me it wont be worth it. That it will cost $88p/h and take up to 6hrs and that does not include materials. I was told that it might not also be possible. They would have to see the unit to really know. I was also told if it was not variable speed it would be trivial to replace the motor for about $350.

PDW
28th August 2012, 03:56 PM
I thought he already said it is not available to his house?

He did but I've heard that from so many people over the years that I basically discount it unless they say that they've *tried* by asking their local power supplier and it's unavailable.

If 3 phase is on the street, it's available. Especially in the 21C with lots of power hungry heat pumps/air conditioners.

Hence my comment WRT location. If he's in the sticks, maybe it's unavailable, maybe not. I'm in the sticks and I have 3 phase. If he's in a city or suburbia, what's the odds it is, in fact, available? How many wires are on the pole out the front?

Whether you want to *pay* for it is a different question....

PDW

variant22
28th August 2012, 03:57 PM
I thought he already said it is not available to his house?

Correct. Thanks for reading BobL. The quote I have from my electrician is 20-25k as I have the driveway from hell.

PDW: I did not realise that sensible advice was location specific? :roll: I also can't help but see the irony when you list your location as "east coast" which holds 80% of the Australian population.

jack620
28th August 2012, 06:07 PM
PDW,
How does knowing where the bloke lives make any difference to the advice you would give him on this subject? He said 3 phase is not available to his house. That was good enough for me. I didn't need proof before offering my advice.

If you "can't be bothered" then why bother posting anything at all?

BobL
28th August 2012, 06:23 PM
Whether you want to *pay* for it is a different question....

PDW

On that basis 3 phase is available anywhere, even on the moon.

jack620
28th August 2012, 06:32 PM
PDW,
I just noticed your location is listed as "Australia East Coast". So you reckon that's OK, but "Australia" is too vague? :?

malb
28th August 2012, 10:23 PM
We had a H+F supplied Soco at work a few years back and it was dual voltage capable, just needed rearrangement of the jumpers in the motor control/jumper box. Would be worthwhile checking whether the unit you are looking at is similar. If it is, a 240/240 VFD would generate 3 phase for you, but you need someone competent to set it all up as you would be bypassing the original control system (Cant switch the output of the VFD at the motor, but can reuse original switch as an on/off switch at the control side of VFD, same with speed switching, use the variable frequency capability rather than pole switching)

If the unit is like the Soco, a motor swap for a different type may not be easy.

variant22
28th August 2012, 10:49 PM
We had a H+F supplied Soco at work a few years back and it was dual voltage capable, just needed rearrangement of the jumpers in the motor control/jumper box. Would be worthwhile checking whether the unit you are looking at is similar.


Malb thanks for your input. I am not really sure what it is but the user manual has a diagram showing the electrical layout of the machine. I have attached a picture of the layout in an effort to find a solution.

jack620
28th August 2012, 11:08 PM
I think SA1 is the speed control switch.

.RC.
29th August 2012, 08:57 AM
It is a two speed motor.... So I am guessing that will complicate things....

What brand of machine is it?

variant22
29th August 2012, 10:08 AM
What brand of machine is it?

It is a Hafco MetalMaster: S828 | CS-315D MetalMaster Cold Saw Includes Stand | machineryhouse.com.au (http://www.machineryhouse.com.au/S828) - Apparently made in Taiwan by the same people that make Thomas Cold Saws.

RayG
29th August 2012, 09:51 PM
Hi Variant22,

The only difference between the 240v model and the 415v model that I can see is the 240v one is 44 rpm only while the 3 phase is 22 and 44 rpm.

The additional cost of getting three phase power seems like a high incremental cost just to get the slower speed.

If you really need the slower speed, maybe there is a cheaper mechanical solution, or get a slower speed 240v motor.

On the other hand, the only solution I can suggest to get 3 phase 415v without too much hassle would be a phase converter, and that's going to set you back a few thousand anyway (unless, of course you make your own )...

Regards
Ray

malb
29th August 2012, 10:48 PM
Looking at the wiring diag, setting up to run 240 3 ph from a 240V in VFD, would be difficult to impossible without major motor work. Can't tell from the pic how heavily intergrated the motor and gearbox are, but the general arrangement of the power head is similar to the Soco, and it was a task specific motor with a long shaft protrusion to mount a worm about 3 inches long, so swapping for a standard motor might not be possible.

variant22
30th August 2012, 12:00 AM
RayG: I need 22rpm for stainless and 44 for mild steel.

malb: Thanks for the notes on the electronics. This is most helpful.

I am going to shut the book on this idea as it clearly seems like it will be a significant cost to get the desired result. It is a real shame they do not make the 315 in the variable speed like the 350 series. The 350 is unfortunately significantly larger in physical size than the 315. Apparently the Brobo 240v does 22 and 44rpm, but unfortunately it also starts at $6k.

jhovel
30th August 2012, 12:28 AM
Variant22, I think you misunderstood what Ray suggested: with a VFD you can have ANY speed you like your motor to do. It's just that at 50Hz it will be configured to run the spindle at either 22 OR 44rpm. Most 3 phase motors are happy to run between 10Hz and 100Hz - so you can have that particular motor drive the blade at any speed between either 4.4 to 44rpm or between 8.8 and 88rpm you choose. Most likely the 2-pole motor option will be the most efficient for cutting a variety of metals from stainless to aluminium - in my humble opinion - with the added bonus of the greatet HP output (motor speed of 2800rpm at 50Hz)... cost to modify the motor around $100 max, VFD around $129. I know what I'd choose in a flash....
Cheers,
Joe

Gerbilsquasher
30th August 2012, 09:12 PM
On that basis 3 phase is available anywhere, even on the moon.

:roflmao:

Give me the time and the money and I'll make the world spin the other way...

I am faced with a similar problem, Spaznet quoted $25k for 3 phase and my machines are too valuable (well, to me anyway) to change simply because I have moved.

My strategy is as follows:

1) Build phase converter for tools with motors (except compressor)
2) Acquire diesel genset for BIG loads/backup power.... eventually.
3) Replace compressor motor with BIG (in this case 480v) motor from supplier such as Weg

Weg Australia (http://www.weg.com.au/)

Have you thought about a bigger single phase motor? Other learned members may correct me if I am wrong, but can you use a VSD on a bigger (say 4 or 5 hp) 240v single phase motor? You would lose the function of the two speed switch and have to replace it with a blanking plate otherwise it would drive me mental.

However once you are bitten by the 3 phase bug I guarantee you WILL be looking out for other machines....

variant22
30th August 2012, 11:53 PM
Variant22, I think you misunderstood what Ray suggested: with a VFD you can have ANY speed you like your motor to do. It's just that at 50Hz it will be configured to run the spindle at either 22 OR 44rpm. Most 3 phase motors are happy to run between 10Hz and 100Hz - so you can have that particular motor drive the blade at any speed between either 4.4 to 44rpm or between 8.8 and 88rpm you choose. Most likely the 2-pole motor option will be the most efficient for cutting a variety of metals from stainless to aluminium - in my humble opinion - with the added bonus of the greatet HP output (motor speed of 2800rpm at 50Hz)... cost to modify the motor around $100 max, VFD around $129. I know what I'd choose in a flash....
Cheers,
Joe

Joe, thanks for the note. I am not really sure how I misread Rays post. I have re-read it a few times and I am still not sure what I am missing.

Having the motor rewound or replaced has significant risk. I mentioned the advice received by the motor rewinding specialists earlier in this thread, and Malb mentioned the motor swap was not likely to be straight forward.

On the surface the risk of buying the machine with an outlay of 2k+ and then finding out it cannot be done is too great. That all being said, I am still open to ideas.

jhovel
31st August 2012, 12:23 AM
The whole idea of a large phase converter seems pointless in a hobby workshop. You usually only ever run one machine at a time. And it is certainly possible to have multiple machines controlled by the same VFD. One of my VFDs is set up with a long cable on the controller so I can walk around with it to other machines and the VFD ooutput is a 3-phase socket. I modified that a little by buiding in a little microswitch wired to the 'stop' contacts of the VFD, in case the plug vibrated loose or I pulled it out with a running VFD by mistake or some other stupity or senility down the track. It was the only VFD I had for years and years (when VFDs were too expensive) and had 3 machines I used it for. I intend using it for a cylindrical grinder and a surface grinder - and maybe a tool and cutter grinder - down the track, because they won't be used a lot and moving the little control panel won't be a problem.

My biggest VFD (physically the smalles by the way) is 3kW and it is happy to drive a 5HP motor - only up to a 3kW load, of course.
There are also 4kW 240V single phase VFDs around, maybe bigger.
Joe

jhovel
31st August 2012, 12:26 AM
Variant22: I read your repy to Ray's message as you thinking you could ONLY have 22rpm or 44rpm - which you know now is not the case. If you dodn;t think that, than I was simply mistaken. Sorry.
I would be surprised if you had to have the motor REWOUND - I expect you will only have to have to have it internally REWIRED. A much cheaper and less complicated proposition.
Cheers,
Joe

Michael G
31st August 2012, 08:23 AM
Joe's suggestion in post 28 is a possible solution but when I was installing my first VFD I was told to keep the distance between the VFD and motor as small as possible, and have that connection with shielded cable. The reason given was because of the type of output of a VFD, they can pump a whole lot of electronic noise into the environment.
If you live on a property (as Joe does I think) this is probably not an issue. However, if you are in a built up area the neighbours (via their TV's) may not appreciate what you are doing. A better alternative may be to mount the VFD on a stand and move it to the machines installing short shielded cables on the machines to plug in from there.

Now that digital TV is sweeping the land interference like this may not be an issue (this advice was pre digital).

Michael

variant22
31st August 2012, 11:04 AM
Joe's suggestion in post 28 is a possible solution

The thing that I am not 100% on is when we/Joe are talking of VFD's are we talking about:

1) 240v single phase to 240v 3 phase?
2) 240v single phase to 415v 3 phase?

And as for the machine are we talking about:

1) 240v single phase saw
2) 415v 3 phase saw

I am not sure if there is the suggestion to run the single phase 240v machine with a 240v VFD (to control the motor speed) or if the suggestion is to run the 415v machine with a 240v VFD?

It would also be good if there was some specificity detailing the changes to the motor that would be required and a link to this $129 VDF for completeness.

Some of the details appear to be lost or implied in the discussion. The details may well be obvious to anyone with a small amount of knowledge, but unfortunately I do not fit into that category - yet. :doh:

jack620
31st August 2012, 11:39 AM
Personally I wouldn't mess with the motor. Just get a VFD to suit. That way if the VFD fails it will be fairly straightforward to return the machine to original.

jhovel
1st September 2012, 02:02 AM
Sorry Variant22, I didn;t make myself clear:
I am talking about single phase 240V into VFD, 240V 3-phase out of VFD, rewiring (internally by motor rewinder) the 415V 3-phase motor to single speed DELTA mode 240V 3-phase. The motor is sold in STAR mode wiring for two different numbers of poles (2 pole: 2880rpm and 4 pole: 1440rpm).
Then using the VFD to regulate the speed to anything you like for different materials.

Single phase motors require a special VFD and that can only be done with motors that don't have centrifugal start switches.
Cheers,
Joe

variant22
3rd September 2012, 09:42 AM
Sorry Variant22, I didn;t make myself clear:
I am talking about single phase 240V into VFD, 240V 3-phase out of VFD, rewiring (internally by motor rewinder) the 415V 3-phase motor to single speed DELTA mode 240V 3-phase. The motor is sold in STAR mode wiring for two different numbers of poles (2 pole: 2880rpm and 4 pole: 1440rpm).
Then using the VFD to regulate the speed to anything you like for different materials.

Single phase motors require a special VFD and that can only be done with motors that don't have centrifugal start switches.
Cheers,
Joe


Thanks Joe, the clarification is just what I needed.

From the wiring diagram above, can you see any reason why the 415v motor could not be rewound? The last thing I want to purchase is a lead weight.

jhovel
3rd September 2012, 07:13 PM
I can't tell from the diagram, but at worst the rewinder will have a bit of fun finding the star point of the two sets of coils. At best it's just a matter of changing over a few terminal blocks.....
In any case, the motor should not need rewinding, just REWIRING.
Cheers,
Joe