Importing german 380v machines to run on 480v - 3 phase

Hi Everyone,

I'm in the process of importing three machines from germany that are all three phase 380v and my shop has 480v.

The machines are forging hammers and have a simple motor to flywheel design so there is no automation or programming necessary; just on and off.

The only thing important for me is to run a very specific RPM to keep the beats per minute the same when we go from 50 htz to 60 htz. I know I can achieve this with VFD's but i still have the voltage issue to deal with.

The motors are 5,7, and 15 hp.

What is the easiest and least expensive way to drop my input voltage from 480v to 380v while at the same time controlling frequency? My thought is to use a step down transformer and basic VFDs on each machine. Any other ideas?

Thanks!

The VFD will control both frequency AND effective voltage. So you can run VFD from 480 and supply 380. 50 Hz.

If you wanted simple, it might be possible to change the motor pulley to 5/6 the present size, and run direct from 480 60Hz. The motor will be OK with that, it's just changing the rpm back to the 50Hz rate.

First, I don't think you have to do anything. The higher inductive reactance of the 50 Hz motors running on 60 Hz will reduce current substantially. I know they will work without issue on 440 60 Hz. You will have the 20% speed increase to deal with though. Perhaps just a simple pulley change is all that's needed.

So the 380v motors will be OK with 480v even if they aren't multi-voltage motors?

opendieforging said:

So the 380v motors will be OK with 480v even if they aren't multi-voltage motors?

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In a nutshell, they ARE "multi voltage motors".

JST - and others - have published "the math" on this a hundred times. It's a Volts/Hz relationship.

380 @ 50 Hz is au fait with the higher voltage @ 60 Hz.

Near-as-dammit same energy under the curve. Same Ergs. Same thermals to deal with.

Most modern motors are actually optimized at 55 Hz in the "Iron and Copper" not "fractional pole count", anyway so as to be "don't care".
Global economy is why.

Japan, for example is half-and half, 50 Hz / 60 Hz on their national grid by historical accident.

Here, RPM is the only real issue.

Fabbing pulleys ONCE trumps buying then maintaining VFD if it really is that stable a need.

If it might CHANGE? VFD it. But not until you need to do.

VFD caps have a finite service life, and it isn't cheap to reset that clock even ONCE.

opendieforging said:

So the 380v motors will be OK with 480v even if they aren't multi-voltage motors?

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Yes, the "volts per Hz" is the same.

The problem lies in the strike rate..... it will be 6/5 of the original when running at 60 Hz. If that is a problem, as you suggested, then you can change the pulley on the motor. (more hassle if it is gear drive).

Oh boy, looks like I'll be taking to the lathe section forum for advice on how to turn my first pulley on my new (to me) 1968 Clausing! Seems like a fun project though. Thanks for all the advice everyone!

Just have to set your motor parameters to 380v 50hz, and adjust frequency back to sync speed. So at run speed you will be back to 50hz.

My crane is a 50hz 380v machine, that's all I had to do was retapped the control transformers and change the couple drive parameters.

Sent from my XT1650 using Tapatalk

opendieforging said:

Oh boy, looks like I'll be taking to the lathe section forum for advice on how to turn my first pulley on my new (to me) 1968 Clausing! Seems like a fun project though. Thanks for all the advice everyone!

Click to expand...

With all the new, NOS, used Browning, Morse, Maska in ever-so durable Cast Iron, and Chicago Die-cast or Congress in ever-so expendable, but also cheaply replaceable ZAMAK out there?

If I made a set at all, it would be PolyVee or MicroVee using a steel "tire" shrunk-onto a hub, QD bushed for my convenience.

Even then, I would goal to buy one, as found, make only a mate to it to nail the ratio wanted.

Decent spring idlers are parts-bin goods, Rockauto or such. UNlike moribund Vee belts, a "serpentine" belt dasn't actually MIND a reverse curve for tensioning.

Need more power transmission capability? Just widen it to add ribs. Their math is actually calculated as (x)HP per-rib, each profile and type.

They all begin life about a meter wide, slit to order as to rib-count. No need to special order. Just go up a rib or three and use one someone else has already made a mass-market for, NAPA listed underhood goods .. or rock-crushers.

What machines are you getting, pics needed
Are they belt and pulley drive or gear drive? My Nazels (Beche) are gear drive

thermite said:

With all the new, NOS, used Browning, Morse, Maska in ever-so durable Cast Iron, and Chicago Die-cast or Congress in ever-so expendable, but also cheaply replaceable ZAMAK out there?

If I made a set at all, it would be PolyVee or MicroVee using a steel "tire" shrunk-onto a hub, QD bushed for my convenience.

Even then, I would goal to buy one, as found, make only a mate to it to nail the ratio wanted.

Decent spring idlers are parts-bin goods, Rockauto or such. UNlike moribund Vee belts, a "serpentine" belt dasn't actually MIND a reverse curve for tensioning.

Need more power transmission capability? Just widen it to add ribs. Their math is actually calculated as (x)HP per-rib, each profile and type.

They all begin life about a meter wide, slit to order as to rib-count. No need to special order. Just go up a rib or three and use one someone else has already made a mass-market for, NAPA listed underhood goods .. or rock-crushers.

Click to expand...

Ok, you just said a whole lot of words that i don't understand. I'm a blacksmith and very new to the world of machine work but loving it so far. I'll just keep reading it till I understand Thanks!

Rob F. said:

What machines are you getting, pics needed
Are they belt and pulley drive or gear drive? My Nazels (Beche) are gear drive

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The machines are: 150kg Beche, 75 kg Eumuco, 60kg Reiter. I already have a 100kg Beche, 40kg Anyang, Little Giant 100, and an Iron Kiss 130 so this should hold me over for a while! Everything is belt drive.

When I set up the 100kg beche, I switched out the motor and pulley for a 10hp 480v and it runs fine. Hoping to avoid having to purchase a new motor this time around.

Those gear driven Nazels are sweet and I'd like to get my hands on one, but this deal was just too good. I got all three hammers for a little more than what 2B would run over here.

opendieforging said:

The machines are: 150kg Beche, 75 kg Eumuco, 60kg Reiter. I already have a 100kg Beche, 40kg Anyang, Little Giant 100, and an Iron Kiss 130 so this should hold me over for a while!

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Might explain certain recent geological faux pas, East Coast, as well.

At least you ain't located in Putnam Township, Livingston County, Michigan, given the IP rights to "The Hammers Of Hell" are already spoken for by a half-tribe of itinerant-if-not-also-merely-alleged "musicians" of a different order.



OEM geardrives of any worth one really dasn't want to mess with trying to alter atall.

opendieforging said:

Ok, you just said a whole lot of words that i don't understand. I'm a blacksmith and very new to the world of machine work but loving it so far. I'll just keep reading it till I understand Thanks!

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Some of that is brands of commercial pulleys that you may be able to use. and belt types. Check local sources, most have them, and the farther out of the city you are, the more likely in some ways.

opendieforging said:

Ok, you just said a whole lot of words that i don't understand. I'm a blacksmith and very new to the world of machine work but loving it so far. I'll just keep reading it till I understand Thanks!

Click to expand...

Finding pulleys - or "sheaves" - on, for example, Google or eBay, goes waay faster if you know in advance that the "cheap stuff" -Vee belted in ZAMAK die-cast comes off certain vendors (historically Chicago Die Cast and Congress, Chinese or India no-name more recently), whilst Morse, Browning, T.B Woods badge-engineered from them, later Maska, made the "industrial" grades in more durable Cast Iron.

QD or Taperlock hubs are found almost exclusively in those CI goods, ELSE steel. MMC stocks both and in US and metric sizes. So, to a lesser extent, do I, as the NOS ones are but a fraction of new cost.

Gates Rubber owns most, if not all, of the surviving general-purpose pulley makers.

Auto industry has them made by stampers and such to shave pennies and fit specific needs. Those LOOK ugly, but are actually rather decent goods if you can re-purpose them for your own needs.

Problem with gearboxes is twofold:

A) Whether or not there is even a place in the driveline where a belted ratio also exists - or can readily be ADDED.

B) Having a care not to provide "too much" torque for any weaker-link downline to stand up to if/as/when you drop RPM - which boosts torque, like it or not.

VFD or DC drive, one just dials-in preferred safe limits. Mechanical is what it is. "Fixed".

Best one can do is apply a shear-pin, more expensive yet speciality clutch, or - opposite direction - cheaper belting so as to assure slip when pushed into the bad corner.

And NOW you can grok "just why" so many things frustratingly have motor pulleys too-tiny for decent wrap, one size too-narrow a belt, and are constantly raising "Why the Hell didn't they use the next size UP!" chronic maintenace headaches.

Often as not, that undersized weakest link in the chain is... a "fuse".



Gates, BTW, has coalesced to online pages much of what used to be really good and nicely simplified "drivetrain" design tools out of both the Browning and Morse dead-tree catalogs once the size of telephone books. Each.

Takes mebbe five or ten pages worth of a wander across those and one has a much better klew what works where. Or not-so-well.

Also why some equipment makers got into problematic implementations as might be not all that hard to improve under your own roof.

Another vote for cast iron taperlocks......dont muck about with rubbish that will wear out in six months.Like aluminium.

Curious, is the switch from 5 to 6 blows per time interval really going to mess you up?

The motor generates the same torque at 480v 60hz as it does at 380 50hz so you get more hp. Worth trying out with no modification in my opinion if the machine is up for it.

johansen said:

Curious, is the switch from 5 to 6 blows per time interval really going to mess you up?

The motor generates the same torque at 480v 60hz as it does at 380 50hz so you get more hp. Worth trying out with no modification in my opinion if the machine is up for it.

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Might be a bit like playing sports. OPERATOR has to have a cadence they are attuned to and effective within. Not just the machine.

VFDs tend to not do well with cyclical load machines like a hammer / iron worker. You don't need one though, the motors are fine with 480V 60Hz. Just change your speed mechanically (sheaves / gears).

Some of those machines actually overload the motor for a short time, and if so, the VFD may not like it..... that is true, and I was not thinking about that point....