Do 230V single phase input / 460V three phase drives exist?

[86turbodsl]

As in title suggests, i have an application that would be perfect for this type of drive. Does such a beast exist?

 

[LKeithR]

You can get from 230 single to 460 3 ph but you need a transformer and a vfd or phase converter to do it. To answer your
exact question I've never seen an all in one unit...

 

[jdsmith]

It's possible to build them but the cost and reliability work out better by installing the step up transformer and a traditional drive. I have not seen one from any of the mainstream vendors, and I wouldn't trust one from some of the oddball vendors.

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[thermite]

As in title suggests, i have an application that would be perfect for this type of drive. Does such a beast exist?

Yes, and since vacuum-tube days, even. Utility, Defence, Telecoms industry suppliers, not your white-bread VFD makers.

Try these folks:

LTI Frequency and Phase Converters

Budget large. Very large. Might be special order, but they do those, MIL-SPEC testing... high-reliability .. the whole nine yards. Won't be their first rodeo.

Or save your time and go find a transformer + white-bread 1-P => 3-P rated "consumable" VFD like the rest of the chik'ns use.

 

[Clive603]

I've no idea why the mainstream vendors don't make such beasts.

Fundamentally the only difference is the input rectifier and capacitor bank configuration. Voltage doubling instead of ordinary bridge set up. Everything else is the same and all the active devices sill see the same 230 V nominal (+ voltage boost). Probably less headroom for voltage boost so torque may not hold up so well once you get significantly away from the motor nominal speed. But I suspect that star configuration may be a little less demanding in that respect than delta. In my view anyone who expects to just fit and run a VFD equipped motor outside the "always OK" ± 1/3 rd nominal speed range without doing proper engineering analysis of the set up is asking for trouble.

Naturally you'd need proper input current reduction chokes and a slow charge on start-up routine inside the controller for an industrial rated system. Capacitor bank needs to be larger too. If its a bigger beast some sort of ripple control intelligence via triac type, actively controlled, rectifier is probably a good idea too.

Fixed frequency device as a Phase Perfect, Rotary Converter or whatever replacement ought to be a slam dunk and cheaper for ordinary one to a machine duties. Donkeys years since I built a fixed frequency one, around about the time the first VFD control integrated circuits and output switching devices became reasonable available, and it really can be very simple. Bloke asked me to do half a dozen static converters for his workshop back when even basic rotaries were nigh on unaffordium for average guy and I wondered if a solid state device would have been cheaper and easier. Surplus shop capacitors and the usual futzing around tuning things won out so went no further. In hindsight shoulda run with it.

I have one of the modified breed fixed at 50 Hz running my workshop. 10 HP rated Teco VFD reworked by Drives Direct in the UK around 2005 used in Plug and Play mode via normal machine controls. Treated just like utility 3 phase. Cruel maybe but it hasn't gone pop yet. Largest motor is 3 HP so starting a machine puts significant demands of the overload capacity of the VFD but it can handle it.

Clive

 

[thermite]

I've no idea why the mainstream vendors don't make such beasts.

Fundamentally the only difference is the input rectifier and capacitor bank configuration. Voltage doubling instead of ordinary bridge set up. Everything else is the same and all the active devices sill see the same 230 V nominal (+ voltage boost). Probably less headroom for voltage boost so torque may not hold up so well once you get significantly away from the motor nominal speed. But I suspect that star configuration may be a little less demanding in that respect than delta. In my view anyone who expects to just fit and run a VFD equipped motor outside the "always OK" ± 1/3 rd nominal speed range without doing proper engineering analysis of the set up is asking for trouble.

Naturally you'd need proper input current reduction chokes and a slow charge on start-up routine inside the controller for an industrial rated system. Capacitor bank needs to be larger too. If its a bigger beast some sort of ripple control intelligence via triac type, actively controlled, rectifier is probably a good idea too.

Fixed frequency device as a Phase Perfect, Rotary Converter or whatever replacement ought to be a slam dunk and cheaper for ordinary one to a machine duties. Donkeys years since I built a fixed frequency one, around about the time the first VFD control integrated circuits and output switching devices became reasonable available, and it really can be very simple. Bloke asked me to do half a dozen static converters for his workshop back when even basic rotaries were nigh on unaffordium for average guy and I wondered if a solid state device would have been cheaper and easier. Surplus shop capacitors and the usual futzing around tuning things won out so went no further. In hindsight shoulda run with it.

I have one of the modified breed fixed at 50 Hz running my workshop. 10 HP rated Teco VFD reworked by Drives Direct in the UK around 2005 used in Plug and Play mode via normal machine controls. Treated just like utility 3 phase. Cruel maybe but it hasn't gone pop yet. Largest motor is 3 HP so starting a machine puts significant demands of the overload capacity of the VFD but it can handle it.

Clive

It's all actually easy as pi if you don't mind "switchers" and kicking the intermediate goods up to right above the audio spectrum so as to use smaller and cheaper components.

I had once snagged a Lorraine inverter built that way that C&W had surplused to run my S-100 gear's UPS.

About 12U rackmount, hugely heavy. Took telco-vanilla nominal neg 48 VDC, a tad more when the pile was in "float" of course, and spit out the cleanest 120 VAC sine wave you could ever ask for.

At all of 5 Amps!



OTOH, Phil-Thai-Oki-Nam IWCS FPTS sites, our Lorraine inverters had filled whole rows. Battery array was run off 3 X Diesel gen sets, two up, one back for PM, 300 KVA each to 1 MVA each. There was no "local utility" power, of course! Same again quite a lot of the old C&W empire, civilian sites.

1960's

Why can't we buy doublers? We can.
They exist in commodity VFD.

Most are 120 VAC in, 240 VAC out though. Over 300 puts them into our NFPA 70 "600 Volt class".

And now we have a mixed-bag, and too many unawareniks whose METERS may not even be safe to use! 4XX in, 4XX out, different sort of folk messing with them, appropriate test gear.

Usually. The four sets of trustworthy HV leads on my Rigol scope cost me more than the scope itself did! Dinosaur Current work. With spikes.

"commodity" is the real key word, though.

All this stuff has gone high-volume, many competitor, razor-thin margin. Make yer short-term bones, ELSE quit that market segment FAST before being beaten to death, economically. The majors kill-off old easily as fast as they introduce new. VFD are starting to resemble the cellphone market, yah?

All about the money, IOW. As usual.

 

[86turbodsl]

Interesting discussion. Sounds like i need to look harder for a 230V device though. I don't think the power costs to run a transformer 24/7/365 is the road i want to roll down.

 

[WHHJR]

Interesting discussion. Sounds like i need to look harder for a 230V device though. I don't think the power costs to run a transformer 24/7/365 is the road i want to roll down.

But it works, is simple, and there are many drives which will work. BTDT got both T shirts.

2¢

 

[86turbodsl]

And the roughly 160w no load cost to have a transformer plugged in really adds up over time.

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[WHHJR]

And the roughly 160w no load cost to have a transformer plugged in really adds up over time.

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Unplug a few wall warts while you are at it.... Besides, put the transformer on the output of the vfd and there will be NO load until you run the machine. If the machine is uneconomical at approximately an additional 1.5C per hour when running you should not be using it.......

10¢

 

[johansen]

Off the sheld line load reactor on the input of a 480v drive connected to 240vac (one line to the rectifier, the other to the midpoint of the capacitors) will be ok for something on the order of 30% of the drive capacity.

Better solution is transformers, and if the no load power consumption is a problem, spend the money on a good toroidal unit (4watts per kva no load, yes really. 1 watt per kilogram core losses)

 

[JST]

And the roughly 160w no load cost to have a transformer plugged in really adds up over time.

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And, out of curiosity, how do you know it is / was 160W?

What kVA of transformer?

 

[thermite]

Interesting discussion. Sounds like i need to look harder for a 230V device though. I don't think the power costs to run a transformer 24/7/365 is the road i want to roll down.

Switchgear exists. Best of all, my NSHO, is What WHHJR said. Use a 3-P transformer load side of the VFD. Free plus is that motor and bearings will be happier, too.

Either way, you don't power it at all if you don't have useful work for it at the far-end. It ain't a damned doorbell.

 

[86turbodsl]

Based on published data for a 5kw transformer which is appropriately sized.

You don't need switchgear for equipment that runs 24/7 and doesn't get powered off because it's doing something continuously.

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[thermite]

Based on published data for a 5kw transformer which is appropriately sized.

You don't need switchgear for equipment that runs 24/7 and doesn't get powered off because it's doing something continuously.

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If it is "doing something continuously" you have the justification for providing power continuously, too.

5 KVA is chickn'-shit small beans, BTW. Solar array and batt'ries can give you that, 24 X 7 X 365. Does do, remote telemetry and comms-relay sites, all over the world. HAS to!

Why are we so worried?

 

[Jraef]

The concept is totally possible, and extremely uneconomical. The VFD would likely cost twice the cost of using a transformer, and the marketplace would support maybe a few hundred per year? Nobody is going to invest that much in something where the PAM (Potential Available Market) is way too small to be viable.

There is (was?) a company in England doing something close, using 230V single phase input and giving 400V 3 phase output. For a few years they sold a version here in North America that boosted to 460V, but they stopped selling them. They never got UL listing for them and at roughly $30k per line item, they couldn't possibly sell enough of them to make it worth doing. True, you don't need UL listing everywhere, but you do in most places.

 

[johansen]

Based on published data for a 5kw transformer which is appropriately sized.

You don't need switchgear for equipment that runs 24/7 and doesn't get powered off because it's doing something continuously.

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Toroid dot com has a 5kw 120v dual primary and secondary isolation transformer medical rated. 780$, 79 pounds, 20 watts no load losses. Due to the .5 to .6 power factor of a single phase rectifier, for a 5kw load you need a 10kw isolation transformer, or a 5kw connected as an auto transformer.

780$ is a bit steep but will pay off the 150 watt loss of a cheap tx about 6 years.

Why not just take 30 minites and rewire the motor for 277 delta and run it from a 230v vfd?

 

[JST]

Based on published data for a 5kw transformer which is appropriately sized.

You don't need switchgear for equipment that runs 24/7 and doesn't get powered off because it's doing something continuously.

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They gave you the loss in watts, I assume?

 

[thermite]

They gave you the loss in watts, I assume?

"Loss" would about run the average yard light, incandescent days.

Power is that dagone dear, shed the fridge/freezer, go over to tinned, smoked, dried, pickled, fermented, or fresh foods.

Worked OK for the Roman empire or Genghis Kahn, didn' they? Or our own G'G-parents and prior.

Still does.

 

[86turbodsl]

I can't rewire the motor. It's hermetically sealed. It was for an experimental heat pump idea I had. Without the 230in 460out drive, the idea makes no sense.

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