Thread: VSD/VFD for those who have SWER power

Hi There,
I have a small Inverter, like the small one in the photo, & it runs my Lathe, & has done for 5years now.
Mine in " SEW EURO DRIVE " Will drive 2HP, but I only have a 1HP Motor
Could not run any better if I tried.
Does not have a speed readout, but I use the Hertz for my speed, but as most of you know, I travel on 3000 RPM most of the time.

I read the manual on the link you provided and am now none the wiser.
Does this unit allow you to run a 3 phase motor on 220v?

Originally Posted by casjon

I read the manual on the link you provided and am now none the wiser.
Does this unit allow you to run a 3 phase motor on 220v?

Not with this unit, but in general you can often run 3ph motors on 230V if the motor is able to be re-wired from star to delta.

This particular unit is only useful if you're on a split-phase SWER supply - it'll allow you to run a 3ph motor at the normal 415V.

Originally Posted by casjon

I read the manual on the link you provided and am now none the wiser.
Does this unit allow you to run a 3 phase motor on 220v?

No. There are many available to do just that, but this one needs 480v single ph input. I believe this is supplied to some rural areas that have need for greater power such as dairies etc. I am on a SWER system, but it is only 240v.

Dean

Something odd here - maybe a misunderstandung or translation error....
SWER stands for "Single Wire Earth Return". 480V rural supplies are two lots of 240V with a common neutral, the phases 180deg shifted. If it is Earth Return (and I have seen this in Harcourt, Vic a few decades ago), it would still require Two wires - so clearly TWER....
Unless there are places in the world where there are just single phase 480V supplies...

Originally Posted by jhovel

Something odd here - maybe a misunderstandung or translation error....
SWER stands for "Single Wire Earth Return". 480V rural supplies are two lots of 240V with a common neutral, the phases 180deg shifted. If it is Earth Return (and I have seen this in Harcourt, Vic a few decades ago), it would still require Two wires - so clearly TWER....
Unless there are places in the world where there are just single phase 480V supplies...

SWER is a single, high voltage conductor with an earth return (for the HV side) as opposed to the more common rural supply using 2 HV lines to provide a single phase supply, the earth only becoming relevant on the LV side of the transformer.

As you say, SWER typically terminates at a transformer that provides a split-phase supply, and this VFD is designed to use the 480V potential that's available between phases.

You are right, of course. It's the secondary side of the transformer where the 480V connection is made - presumably with a dual secondary winding in opposite diirections to get two lots of 240V with opposite phases. My misinterpretation not theirs

I only posted the link thinking it may be interest/use to some

no point asking me for the finer details........ as I dont know..lol

Note that not all 480V split phase systems are SWER. We run off a 2 wire HV system that provides 480V split phase.

Originally Posted by Vernonv

Note that not all 480V split phase systems are SWER. We run off a 2 wire HV system that provides 480V split phase.

I keep on forgetting that - it's not something I've seen in my area, but would be a good option for a lot of the wineries in the region who only have 2-wire supplies and are stuck with a single 240V supply, meaning they all hire in generators to sit beside their wineries for the duration of the vintage, as almost all the winemaking gear is 3ph.

Hi all,
My power supply is from an 11kv to 480v transformer. I believe the secondary winding (480v) is centre tapped for the neutral. Phase to phase volts is 480v, phase to neutral is 240v so I effectively have two 240v supplies and one 480v supply.

Regards Peter

Originally Posted by 2sheds

Hi all,
My power supply is from an 11kv to 480v transformer. I believe the secondary winding (480v) is centre tapped for the neutral. Phase to phase volts is 480v, phase to neutral is 240v so I effectively have two 240v supplies and one 480v supply.

Regards Peter

I never realized before, but I think you could run a solid state phase perfect style converter from a split phase 480V supply..... the idea is that you generate a third phase at exactly 90 degrees to the 0 and 180 240v phases. You end up with perfect three phase.

Could be a good way to get 3 phase from SWER... they are used a lot in the USA with their 110+110=220V systems http://www.phaseperfect.com/

Ray

Originally Posted by RayG

..... the idea is that you generate a third phase at exactly 90 degrees to the 0 and 180 240v phases. You end up with perfect three phase.

Isn't that what a phase converter (rotary or static) does? But maybe I'm missing something?

Also with the angle of the phases, you will certainly have 3 phases, but they won't be 120º apart, but rather 90º?

The phase perfect converters have equal voltage on each leg... Rotary ones certainly do not...