VFD 220v single phase to 380v three phase.

[Neale]

I run a lathe with 3HP motor off a VFD with voltage-doubler input. It's a bit of a bodge put together some years ago by a company now out of business. The nice bit is an ABB inverter originally designed for 415V/3P in and out. The third party replaced the input 3-phase bridge with a voltage doubler running off 240V/1P in. It works fine, except towards the upper end of its load capacity. My lathe has a mechanical variable-speed arrangement so I leave the VFD on 50Hz but as the VFD load increases with increasing lathe speed, somewhere north of 2K RPM the DC bus ripple voltage trips the fault-detection circuitry and the thing shuts down with an "input phase error" message (or similar - haven't seen it for a while as I tend to keep the speed down). I'm assuming that the bus capacitors are being, in effect, charged at 25Hz and the voltage sag between input pulses becomes too great.

I have looked longingly at these Ecogoo devices, and I wonder if they actually use a switching voltage boost on the input rather than a simple passive doubler. Also wondered about just putting a chunky transformer plus bridge rectifier in front of my existing VFD but haven't stumbled across anything cheap enough to play with yet.

[Chaz]

I run a lathe with 3HP motor off a VFD with voltage-doubler input. It's a bit of a bodge put together some years ago by a company now out of business. The nice bit is an ABB inverter originally designed for 415V/3P in and out. The third party replaced the input 3-phase bridge with a voltage doubler running off 240V/1P in. It works fine, except towards the upper end of its load capacity. My lathe has a mechanical variable-speed arrangement so I leave the VFD on 50Hz but as the VFD load increases with increasing lathe speed, somewhere north of 2K RPM the DC bus ripple voltage trips the fault-detection circuitry and the thing shuts down with an "input phase error" message (or similar - haven't seen it for a while as I tend to keep the speed down). I'm assuming that the bus capacitors are being, in effect, charged at 25Hz and the voltage sag between input pulses becomes too great.

I have looked longingly at these Ecogoo devices, and I wonder if they actually use a switching voltage boost on the input rather than a simple passive doubler. Also wondered about just putting a chunky transformer plus bridge rectifier in front of my existing VFD but haven't stumbled across anything cheap enough to play with yet.

Ive got 2 at home. One is powering my surface grinder which is not being used at the moment. If you wanted to take a look at the VFD (non destructive of course, let me know).

[m_c]

Neale, Drives Direct are more than willing to provide you with such a setup new, at fantastically wallet emptying prices.

I have looked at building something, but I've never been able to find what VFDs are suitable for online/load switching.

non destructive of course

There's no fun in that!

[Chaz]

Neale, Drives Direct are more than willing to provide you with such a setup new, at fantastically wallet emptying prices.

I have looked at building something, but I've never been able to find what VFDs are suitable for online/load switching.



There's no fun in that!

I spoke to Direct Drives. Pricy and when you mention CNC they say 'no sure if that load would work'. So clearly too risk / pricy to experiment.

[Neale]

I spoke to Direct Drives. Pricy and when you mention CNC they say 'no sure if that load would work'. So clearly too risk / pricy to experiment.

Not quite sure what CNC has to do with it! At least some of the 240-415 inverters on their eBay site come with remote control pods and external CNC control is effectively only replacing the remote controls in the box. But at £600+ for a 3HP box, it's a bit steep.

Thanks for the offer of letting me look at one of the Ecogoo systems but at 200miles distance in South Devon it's a bit far. Kind offer, though. From your experience it sounds as if one of these would suit me anyway, so I'll see what Father Christmas puts in my stocking. Or at least I'll see what's left in my wallet the other side of Christmas!

[Chaz]

Not quite sure what CNC has to do with it! At least some of the 240-415 inverters on their eBay site come with remote control pods and external CNC control is effectively only replacing the remote controls in the box. But at £600+ for a 3HP box, it's a bit steep.

Thanks for the offer of letting me look at one of the Ecogoo systems but at 200miles distance in South Devon it's a bit far. Kind offer, though. From your experience it sounds as if one of these would suit me anyway, so I'll see what Father Christmas puts in my stocking. Or at least I'll see what's left in my wallet the other side of Christmas!

I think its due to the load being variable and possibly 'choppy' if you think that the drives are doing their own trickery.

No problem, always welcome. We are property hunting and whilst your area is appealing, not sure we will head out that far. One of my team members at work lives in South Moulton.

[Voicecoil]

I
I have looked longingly at these Ecogoo devices, and I wonder if they actually use a switching voltage boost on the input rather than a simple passive doubler. Also wondered about just putting a chunky transformer plus bridge rectifier in front of my existing VFD but haven't stumbled across anything cheap enough to play with yet.

They ought to if they want to have any chance of meeting the relevant regulations! The circuit in question is a thing called a PFC boost converter, these are used on the front end of most high power switch mode power supplies, but are normally wired to generate 350...400V DC output which is then either regulated down to a lower voltage or turned into 3 phase 220V AC. It's not a lot of work to make one that outputs 550...600V or so which you can make 380/415V 3 phase from.