Minor Rant

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itasca_mn

Member
Location
Minnesota
I'm perplexed. I work in the electrical department at a Minnesota State University. Over the years, several various departments on campus have ordered new tools and lab equipment. Most of this equipment is intended for use in large commercial applications. Examples of some of these machines are, milling machines, CNC, Autoclaves, Spectrum analyzers, etc. It seems to never fail that these devices are designed to operate at 230-240 volts, and often times the manufacturer will not want this equipment connected to 208 volts. I just recently connected a new Autoclave, that requires single phase 230-240 volts. The manufacturer provided an optional boost transformer to bring the voltage up to acceptable levels. Why would these machines be designed so often to operate at 240 volts, when they have to know that a majority of the time they will be used at facilities that most often will only have 3-phase WYE power?
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
I'm perplexed. I work in the electrical department at a Minnesota State University. Over the years, several various departments on campus have ordered new tools and lab equipment. Most of this equipment is intended for use in large commercial applications. Examples of some of these machines are, milling machines, CNC, Autoclaves, Spectrum analyzers, etc. It seems to never fail that these devices are designed to operate at 230-240 volts, and often times the manufacturer will not want this equipment connected to 208 volts. I just recently connected a new Autoclave, that requires single phase 230-240 volts. The manufacturer provided an optional boost transformer to bring the voltage up to acceptable levels. Why would these machines be designed so often to operate at 240 volts, when they have to know that a majority of the time they will be used at facilities that most often will only have 3-phase WYE power?
Maybe not designed for use in USA?
There are a few other countries in the world you know.......................:D
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I find that often the people ordering equipment don't seem to know the difference between 208 and 240 volts. If in your case that equipment is only manufactured for 230/240 then it's a good question. Could be designed for Europe or somewhere else. :)
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
I find that often the people ordering equipment don't seem to know the difference between 208 and 240 volts. If in your case that equipment is only manufactured for 230/240 then it's a good question. Could be designed for Europe or somewhere else. :)
Isn't 208V usually 3-phase?
Three phase in the EU is 400V nominally.
 

MAC702

Senior Member
Location
Clark County, NV
My minor rant is always about thread subject lines that are some kind of tagline instead of the actual thread of the subject.

But it's a good question.

Only the Americas are likely to have 208V. Everyone else is already a 230V nominal. Factor in several places in the Americas that are 240V instead of 208V and that will be the lion's share of the world market. Most equipment is very tolerant of voltage, especially in the digital age, even motors, and it's likely they just don't bother including that on the label. It's probably a salesman somewhere adding the boost transformer for you. But I still said "most," "likely," and "probably."
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I'm perplexed. I work in the electrical department at a Minnesota State University. Over the years, several various departments on campus have ordered new tools and lab equipment. Most of this equipment is intended for use in large commercial applications. Examples of some of these machines are, milling machines, CNC, Autoclaves, Spectrum analyzers, etc. It seems to never fail that these devices are designed to operate at 230-240 volts, and often times the manufacturer will not want this equipment connected to 208 volts. I just recently connected a new Autoclave, that requires single phase 230-240 volts. The manufacturer provided an optional boost transformer to bring the voltage up to acceptable levels. Why would these machines be designed so often to operate at 240 volts, when they have to know that a majority of the time they will be used at facilities that most often will only have 3-phase WYE power?

On a global scale 230 volt L-N supplies are tens of thousands times more common then P-P 208 volt supplies. Even in South America distribution is 127/220Y, so 220 volts phase to phase.
 

kwired

Electron manager
Location
NE Nebraska
If said equipment requires single phase supply I can see it more likely to only be offered intending to be supplied with 240 volts nominal.

If it requires three phase supply, it likely can be ordered for 208, 240, 480 and even 600 volts in some cases.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
190205-1007 EST

Why not 240? One gets 15% more power for the same current.

The CNC machines I have have taps for different voltages. If the source is 480, then a stepdown transformer is used.

If something needs a heater, then again 240 is better because of the greater available power from a specific wire size.

In our area we have a great many 240 wild leg deltas. Really a good way to do distribution. Usually one large single phase transformer. Added to this is another smaller transformer to provide 3 phase output. No secondary circulating current. If three phase load goes up add a third transformer. This adds circulating current. So possibly better to change the wild leg to a larger transformer.

.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I've run into US market soft-serve ice cream machines that really did want 230-240v. Even resetting the switch inside (I think that was just control power), they just didn't do well on anything below about 225.

In some parts of the country a lot of small stores like ice cream shops are fed by 120/240 single phase- so I guess that may be it.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
It's FROM a 3-phase service, but any 2-pole single-phase equipment on it is still 208V instead of the 240V that most single-phase services will provide pole-to-pole.
Yes, if. Clarification from the OP would be helpful.
 

kwired

Electron manager
Location
NE Nebraska
Yes, if. Clarification from the OP would be helpful.
Since he is on a college campus, the chances are pretty good 208/120 three phase wye is readily available in most buildings. There is a pretty good chance that most of the time it gets derived from 480/277 three phase also, so 480/277 also has a chance of being acceptable for equipment supply ratings at his campus.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Since he is on a college campus, the chances are pretty good 208/120 three phase wye is readily available in most buildings. .
But the complaint is that the kit being purchased is 230V for intended for use in large commercial applications which might infer three phase.
 

sameguy

Senior Member
Location
New York
Occupation
Master Elec./JW retired
Due to those doing the ordering/ specifying don't have a clue to what power is needed or available; then we do what we do to make it work. They rarely realize the steps they may or may not cause; if only they would ask before ordering.
 

growler

Senior Member
Location
Atlanta,GA
Why would these machines be designed so often to operate at 240 volts, when they have to know that a majority of the time they will be used at facilities that most often will only have 3-phase WYE power?

Why do people keep ordering machines that don't match the supply voltage available?

With a quick search you can find equipment designed to operate on 3-phase 208V. It's not like they stopped manufacturing it.
 

kwired

Electron manager
Location
NE Nebraska
But the complaint is that the kit being purchased is 230V for intended for use in large commercial applications which might infer three phase.
I would think a lot of equipment like he is referring to can be made in multiple supply configurations, some even with multiple voltage ability in a single unit. HID lighting is becoming extinct when it comes to new units produced, but that is one example of an item that was commonly able to run a single unit on multiple different supply voltages.

I still leaning toward the bigger issue being whoever submits the order for said equipment has no idea what to order and only a few cases of only just one supply voltage being possible for the item ordered.

Majority of equipment made for where you live is 240 volts if single phase and 415 if three phase. but most of the time that is about only choice you have without a specially transforming to some other voltage. Here for better or worse - we have more common voltages to choose from.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
I would think a lot of equipment like he is referring to can be made in multiple supply configurations, some even with multiple voltage ability in a single unit. HID lighting is becoming extinct when it comes to new units produced, but that is one example of an item that was commonly able to run a single unit on multiple different supply voltages.

I still leaning toward the bigger issue being whoever submits the order for said equipment has no idea what to order and only a few cases of only just one supply voltage being possible for the item ordered.
Probably about the size and substance of it. That said, the user should not depend on the technical ability of a buyer. Document everything.
 

JPinVA

Senior Member
Location
Virginia
Due to those doing the ordering/ specifying don't have a clue to what power is needed or available; then we do what we do to make it work. They rarely realize the steps they may or may not cause; if only they would ask before ordering.

This is critical. Most Everyday Joe consumers (with just enough technical knowledge to be dangerous) know 120/240, because that's what they live with at home. Very few understand there can be a difference between what they get at home and what they get at work. So when ordering, they see several choices, and will pick the one they are familiar with. Which, to someone with enough knowledge to be dangerous, would be the obvious choice...to them.
 

kwired

Electron manager
Location
NE Nebraska
This is critical. Most Everyday Joe consumers (with just enough technical knowledge to be dangerous) know 120/240, because that's what they live with at home. Very few understand there can be a difference between what they get at home and what they get at work. So when ordering, they see several choices, and will pick the one they are familiar with. Which, to someone with enough knowledge to be dangerous, would be the obvious choice...to them.
Many Everyday Joe's don't know there is 208 and 240 nominal systems either. Often times they get lucky and a piece of equipment is rated for either voltage, or even if not possibly works anyway, just may have warranty issues if manufacturer finds out it was applied improperly.

Then you get those that order single phase machine because it cost less, though maybe three phase machine may have been better overall selection for various reasons, or that 208-230 volt machine cost less but then find out it needs more transformer capacity or other costs than if they would have went with 480 that was more readily available.
 
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