690V Equipment in America

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hammbone

Member
Location
Indiana
Hello Forums!

This is my first question on here! :)

I have a very large (2000hp+) motor that requires 690V. We are in the early design process and the motor HAS to be 690V.

It's a non-UL voltage and is sadly just above the cut-off for low voltage into medium voltage.

So it seems that I have to use all medium voltage equipment (disconnects, cabling, ext). Made worse by the fact I need to keep it shielded (going to be a very expensive cable). Do I have to use everything rated 5kV?

Is there some kind of IEC equipment that I can use?
I mean there has be equipment built for the purpose of large ampacity 690V loads, where can I get it?
Can I use this equipment in the States?
What code issues will I run into? Or do I just do everything based on voltage ranges? (For example, 600-5000v is a certain safe working clearance. However, piece of enclosure equipment {I think} that is above 600V needs to be certain size and treated like medium voltage)
Can some of the medium voltage rules be 'softened' up, or I have to design all nearly all components as if they were up too 5000V.

Thanks! :)
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
There are specific rules in most chapters that pertain to voltages over 600. Article 100 part III is pertinent and art. 450 Part III for transformers. I doubt there are leniency rules when it comes to voltages over 600v
 

hammbone

Member
Location
Indiana
There are specific rules in most chapters that pertain to voltages over 600. Article 100 part III is pertinent and art. 450 Part III for transformers. I doubt there are leniency rules when it comes to voltages over 600v

Thanks for the reply.

Do you know of any code sections that pertain to using IEC equipment along with UL?

I'm kind of concerned about internal construction methods/rules/codes being one thing in Europe and then having the equipment be unacceptable in the States.

Do you know if rep's give out IEC catalogs?
 

hammbone

Member
Location
Indiana
When you say shielded do you mean as in shielded cable for VFD usage?





Or shielded as in this:



View attachment 7084


Not sure of the shielding that will be required, just mentioned in a meeting. I'm assuming closer to your photo, because the device it's hooking into isn't really a VFD it's more a custom built control cabinet. The idea is to keep the signal as clean as possible naturally. I'm actually not aware of what the difference would be between the two options.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't believe OSHA accepts IEC 60601 which is for medical equip. I believe. I would check with local authorities.

One of our mods is from Indiana and he may be able to shed some light on it. I'll skype him and see if he is around.
 

iwire

Moderator
Staff member
Location
Massachusetts
So it seems that I have to use all medium voltage equipment (disconnects, cabling, ext). Made worse by the fact I need to keep it shielded (going to be a very expensive cable). Do I have to use everything rated 5kV?

And I will point out the labor will likely run much higher as the number of electrcal contractors qualified to work on systems above 600 volts is much less than below 600 volts.

Of course they are out there but they also charge higher rates.
 

hammbone

Member
Location
Indiana
Master -

I don't know what type of shielding I need to be honest. I think it will not be made for VFD. It has to be very heavy duty. All I know is that we will need it. I'm kind of inexperienced in cable shielding specifications.

Dennis -

I'm trying to figure out if/how I can use IEC equipment in the states. And where I can find it. I guess there are IEC rated breakers, do I need to use medium voltage switchgear housing or low voltage?
That sort of stuff really has me off my home turf.
 

Besoeker

Senior Member
Location
UK
Hello Forums!

This is my first question on here! :)

I have a very large (2000hp+) motor that requires 690V. We are in the early design process and the motor HAS to be 690V.

It's a non-UL voltage and is sadly just above the cut-off for low voltage into medium voltage.

So it seems that I have to use all medium voltage equipment (disconnects, cabling, ext). Made worse by the fact I need to keep it shielded (going to be a very expensive cable). Do I have to use everything rated 5kV?

Is there some kind of IEC equipment that I can use?
I'm from UK. We've manufactured and installed a fair few 690V drives.
For power we use cable that is termed LOW voltage and rated as 600/1000V (phase to neutral and phase to phase). And, as it's UL rated, you could probably find importers there who might stock it or be able

Similarly, with switchgear. Most of the main players like ABB supply switchgear that's rated for 690V.

But I don't know what, if any, code issues you'd have to deal with.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
There is some 1000V rated stuff out there. Not real common though.

You would have to comply with the >600V rules in the code.

I would talk with the AHJ first.

Just curious - why does it "have" to be 690V? Is this a piece of equipment someone bought and had shipped here without realizing there was a voltage issue? Or is it a type of equipment that is not available in US std voltages? If it is the latter, you are more likely to get some dispensation than the former.

I think Siemens has some UL listed contactors and soft starts that are rated up to 850V. Don't know about that big of a motor though. Something that big is in a world of its own. I am pretty sure AB has some rated for this voltage as well.

Maybe the AHJ would accept a design that has your seal on it in lieu of a listing.
 
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Besoeker

Senior Member
Location
UK
Just curious - why does it "have" to be 690V? Is this a piece of equipment someone bought and had shipped here without realizing there was a voltage issue?
I think, from the mention of the IEC in the first post, is would be reasonable to infer that it was sourced in the EU zone.
That said, although 690V drive systems are not uncommon, isn't a standard distribution voltage here either. It has to be transformed on a unit by unit basis from one of the standard voltages, usually higher. Say 11kV[/QUOTE]
 

hurk27

Senior Member
Where are you at here in Indiana?
Our POCO will require a special service or soft start or VFD for a motor of that size, about the only place around here is the steel mils that have their own generation plants is where a motor of that size would be found, unless it is an auto stamping plant?
 

hurk27

Senior Member
Just want to add plant like the steel mils have allot of 4160 that could be transformed down to 690, but will be very un-common in smaller plants. and if it is going to be run off the grid will require a stiff feed from the nearest sub station. I presume you have already worked this part out with the utility.

I would consider transforming right at the motor to save the MV run cost? but transform from what? 600 volt?
 

Besoeker

Senior Member
Location
UK
Where are you at here in Indiana?
Our POCO will require a special service or soft start or VFD for a motor of that size, about the only place around here is the steel mils that have their own generation plants is where a motor of that size would be found, unless it is an auto stamping plant?
I sometimes deal with motors of a similar size or greater.
Petrochem, cement works, paper mills, petrochem etc.
Because of what we do, we generally get involved in such projects only when there is electronic control involved - either a soft start or a VSD.
One such was 6650 kW (about 9,000 HP) and it was in a remote location. It was fed directly from the 11kV supply into the plant but, of the rural location, the supply wasn't sufficiently robust to tolerate direct on line starting. From memory, all of those of 1MW or above have been either 3.3kV or, more commonly, 11kV.
We recently looked at replacing an ageing 11kV drive with 690V as one of the options. That was very soon dismissed because the cabling costs were nearly as much as the drives.

And, in a nutshell, that's a major factor for going to higher voltages. Reduced current.
At 2,000 HP 690V, it's still a lot of current.
2000HP equates to about 1500kW and a simple approximation is that the current and kW are about the same for a 690V motor. So, in this case, 1500A. Big amps, big conductors.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
small world. This was the first I heard of a 690 volt motor, then out of the blue I was asked today about a 50 HP motor which reportedly is marked 690/400 volt. Is 400 volt a normal voltage for a dual winding on a 690 volt motor ?
 

kwired

Electron manager
Location
NE Nebraska
small world. This was the first I heard of a 690 volt motor, then out of the blue I was asked today about a 50 HP motor which reportedly is marked 690/400 volt. Is 400 volt a normal voltage for a dual winding on a 690 volt motor ?

I don't know but if you had a 690 volt wye system the voltage from each phase to the neutral point should be 400 volts.
 

kwired

Electron manager
Location
NE Nebraska
Our POCO will require a special service or soft start or VFD for a motor of that size...

I doubt that there is any POCO that would be willing to just suddenly supply a single 2000 HP motor where no similar load previously existed without some planning and building/rebuilding of distribution before the thing is ever turned on for the first time. :)
 
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