Thor, or should that be Zeus?

[battwell]

I know voltage increasing VFDs do exist, but I can't see anything on either the Huanyang or Ecogoo sites/manuals about those VFDs being able to boost voltages.

You can run 380V three phase motors from single phase using 230V single phase, however once you reach a certain frequency (roughly 2/3 of max rated frequency IIRC), the power available becomes voltage limited. Above that speed you can't get full power, as the voltage isn't high enough to overcome the back emf and drive the required current through the windings, so the available torque drops of as speed increases.
Inverters Direct (aka Drives Direct) supply 230 to 380V VFDs. I did look into them and they are a commercial make (I did have the make/model, but can't find it) with lots of Drives Direct stickers on them. The non-rebadged inverters are available cheaper, but I suspect Drives Direct are doing some internal modifications to boost the input voltage.

The easiest way to achieve it, would be a 250 to 380V step up transformer, big bridge rectifier, and bank of suitable capacitors, and feed the resulting 540VDC direct into the inverters DC bus. That way you bypass the VFDs own rectifier circuits (you could feed the 380V single phase directly in, however you risk overloading the VFDs internal rectifier circuit, and overheating the internal smoothing capacitors due to the increased ripple from only having a single phase supply).
The other option, which is what I suspect Drives Direct are doing, is using a suitable oscillator circuit and inductors to do the boosting, as it would result in a far more compact system.

I'd like to get my hands on a Drives Direct VFD to see just exactly what they are doing, but I'm not willing to pay their prices, and I don't think anybody who has bought one, would be willing to let me dismantle it to have a look.

No need- its all done in the dual stage vfds i have! perfect 380v. under £400 so why mess about. i have them running hsd spindles and a big hydrovane in my workshop for over 2 years now. i test all spindles i sell using the newer ecogoo 9100 :-)
its the only one that can output to the frequencies i require - standard up to 650 hz and special order to 800hz

[m_c]

No need- its all done in the dual stage vfds i have! perfect 380v. under £400 so why mess about. i have them running hsd spindles and a big hydrovane in my workshop for over 2 years now. i test all spindles i sell using the newer ecogoo 9100 :-)
its the only one that can output to the frequencies i require - standard up to 650 hz and special order to 800hz

Finally found a link to the inverters on Aliexpress (https://www.aliexpress.com/item/VFD-...836555598.html)
And the full range can be found on ecogoo website at http://www.ecogoo.com.cn/product-category/220-380
There seems to a bit inconsistency with their model numbers though, but if you get the model number for the size of inverter you'd like on the ecogoo site, searching for it on aliexpress narrows the results.

Some do seem to need derated though. The 7.5KW mentions on the aliexpress listing that it's only suitable for up to 5.5KW motors.

I might get one to try on my big mill, as that's next on the retro list.

[Chaz]

Same one?

http://www.ecogoo.com.cn/product/7-5...80v-output-vfd

This looks like the one that will work ...

Which I believe is this - BG part number.

https://www.aliexpress.com/store/pro...136e968adao0Ns

[Neale]

I'm interested in this as my lathe currently runs from an inverter from an outfit that took an ABB inverter (380-380) and fiddled with it. This outfit, no longer in business, seem to have put some kind of voltage-doubler circuitry on the input. The inverter is excellent, but the problem is that the input circuitry cannot handle heavier loads and there is too much ripple so that the inverter trips out. It's a 5HP (4KW or so) inverter driving a 3HP motor so that bit is well within its ratings.

I keep wondering about finding a suitable 240-380V transformer as per m_c's suggestion but these don't come cheap. So the Ecogoo inverters look interesting, but I'm not sure what the performance would be like at 50Hz as I'm running a conventional 50Hz motor. The motor isn't suitable for rewiring for 240V, unfortunately.

[battwell]

i run a heavy load 380v 4kw hydrovane off one- at 50hz. 3 second start up- coast to stop (doesnt like to try to slow down a hydrovane- as they stop near instant when power comes off . it draws just over 30 amp to start it - but drops to 6.9 running it. - so at 380v 50hz they perform well. at 220v i doubt the motor would start at all .
every machine in my workshop is industrial- and they all run off seperate vfds .
if anyone buys the ecogoo 9100 and needs to run modbus- i wrote instructions as they are non existant in the manual!

[Neale]

That sounds good - should suit a lathe where start-up loads are smaller. I don't need the variable speed as the lathe has a continuously-variable pulley system anyway, but I suspect that this is a fairly big load in itself at higher speeds. I'll look more closely at the Ecogoo boxes. Thanks for the pointer.

[Chaz]

i run a heavy load 380v 4kw hydrovane off one- at 50hz. 3 second start up- coast to stop (doesnt like to try to slow down a hydrovane- as they stop near instant when power comes off . it draws just over 30 amp to start it - but drops to 6.9 running it. - so at 380v 50hz they perform well. at 220v i doubt the motor would start at all .
every machine in my workshop is industrial- and they all run off seperate vfds .
if anyone buys the ecogoo 9100 and needs to run modbus- i wrote instructions as they are non existant in the manual!

I think Ill order one, just checking to see what my bonus was for last year (paid next week, yay). Do you have one spare by any chance that I could buy?

[battwell]

i only have my spare here- which i keep for testing - and in case of failure on any of my machines. they didnt take long to arrive

[Chaz]

i only have my spare here- which i keep for testing - and in case of failure on any of my machines. they didnt take long to arrive

Ok, thanks.

[Chaz]

i only have my spare here- which i keep for testing - and in case of failure on any of my machines. they didnt take long to arrive

Hi,

Do you think this would work?

https://www.reichelt.com/gb/en/from-...F&trstct=pol_9

How close to 50Ohm must it be?