Thread: 240v 15a in 415v 3phase out - options?

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.

Originally Posted by jack620

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?

Hi,
Yes there is, though its more like $600
items in Drives Direct Inverters LTD store on eBay!
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

Originally Posted by Stustoys

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

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.

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

Originally Posted by Stustoys

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?

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

Originally Posted by variant22

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

Originally Posted by PDW

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?

Originally Posted by Stustoys

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.

Originally Posted by BobL

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

Originally Posted by BobL

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? I also can't help but see the irony when you list your location as "east coast" which holds 80% of the Australian population.

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?

Originally Posted by PDW

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

PDW

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