What voltages for USA ?

[kekrahulik]

just to chime into the conversation...the 100yr old plant that I previously worked at had 25 cycle (25Hz) for some old equipment and an elevator.

 

[JesperMP]

Actually, there is 3-phase 240V as well.

in the US there are also motors with windings switchable between series or parallel with voltage ratios of 2, for example 240/480V.

I was hoping I could limit the options to just the most popular.
Does it make a difference that the industry is a power hungry one ? There will be melting furnaces.
I mean that I suspect that the lower voltages are only used in less power hungry facilities. So I can possibly ignore them ?

Make no assumptions about grounding style/quality etc tho. Thar be dragons.

We never assume anything. All details are clarified before signing the contract.
This is about if we can offer some certain voltages as standard. If the customer does not have one of our standard voltages, then it will trigger a special price.

600vac for Canada's auto industry. Obviously it will be plant specific.

Both 600V and CSA are being considered. It is a question if it is worth the effort to make a standard, or if it shall trigger a special price if there is customer with 600V or CSA.

At the moment I have these variants which I believe covers 98% of the globe.
200-220V 50Hz IEC
380-440V 50Hz IEC
200-220V 60Hz IEC
380-440V 60Hz IEC
480V 60Hz UL

 

[JesperMP]

just to chime into the conversation...the 100yr old plant that I previously worked at had 25 cycle (25Hz) for some old equipment and an elevator.

OK, I think I can limit it to new plants, newer than 1970.

All plants built since the 70's, were 480/277(3ph)

 

[Tom Jenkins]

In general, the non-US suppliers I work with have standardized on 480 Volt 3-Phase 60 Hz. When they hit a Canadian or other requirement for different voltages they simply add a transformer to the package. That is more economical than multiple versions of the equipment.

 

[joseph_e2]

At my last place, we had aluminum melting furnaces. The power supplies were fed by 6-phase 480V via 2x 3-phase transformers. One wired delta-delta, the other delta-wye. Primaries were 12kV from the utility.


There and at my current place, general plant voltage is 3-phase 480V. Transformer secondaries were all wye-wound with grounded neutrals. Most of the overhead busways are 3-wire plus ground with a few (for lighting and HVAC systems) are 4-wire plus ground. Bringing out the neutral lets you get 277VAC.

 

[John Morris]

I have worked in production facilities that only ran on 208 3 phase. The only advantage i could see was there was no need for control transformers.

All other plants I worked in were 480. 277 was for the high bay lighting.

 

[mylespetro]

Speaking as a Canadian, I almost always see equipment intended for the US at 480VAC 3-phase. One customer in particular has both a standard (for around here) 600V service and added a 600-480V transformer and a 480V panel because they were buying a lot of equipment from America.

 

[5618]

480V is the standard for most DOL and VFD motor driven machinery. I see 208V often in packaging machines where motion is mostly servo, stepper, and pneumatic.

 

[PLCDontUQuitOnMe]

Plant I work in now has a xfer providing 600v to the plant. However on the floor we have a lot of equipment from Germany where they will put a 600v/460v xfer in the machine. Of course there are plenty of other xfers around the plant to provide all sorts of other voltages.


Plant I was in before was Japanese (in Canada) which I believe was fed 600v from the city but had large 600v/480v transformers in the main electrical room to feed most of the Japanese built machines. The only way you'd know we even had 600v there was if you worked on the plant lighting, which was 347v.



I believe most plants will have similar setups: incoming voltage from the city and then lots of xfers to lower/raise voltage to whatever is needed for various pieces of equipment.

 

[I_Automation]

120/208 3Ø is "old school" USA, and not commonly installed in new buildings



120/240 3Ø is then new standard for smaller shops and rural areas
EDIT: While 220, 230 & 240V are interchangeable 240 & 208 are not commonly -except a few components may work on both.



277/480 3Ø is the most common


575 is Canadian. I have built 3 machines to be shipped there, the first one I didn't have access to a 480-575 transformer so it was built and tested with 480 motors, tested, then all the motors and control transformer were swapped for 575 to ship. I think that shop still had those motors on the shelf when they closed.



600 IS used in America mostly for shops with a lot of welders. I was taught welding in a shop in the Detroit area that was 600. The welding machines that had motors were 600V motors.


Then the foundry in my area that closed a few years ago had everything medium voltage - 2,500V. Plus there's an anti-freeze pumping station at Detroit Metro Airport that has 7 very large pumps that I'm guessing are medium voltage too, as 480V wiring to each motor would be hi amperage and 4" diameter wire.

 

[bill4807]

80% of our machines from asia are 220V.
When we ship them to our customers i either supply them with a transformer to exchange from 480 to 208/120, or they hook it to a 220 bus.
If we build a machine here in the US i ask the customer what they have available, most of the time it is 480 so we build it to that.
Mostly automotive/medical.

 

[dogleg43]

Most truly industrial plants in the USA will have 277/480VAC 3-phase for power. If the plant is in a strip mall or small industrial park then it may only have 120/208VAC 3-phase.

For general purpose things like lighting, convenience receptacles, and the like it’ll be 120VAC although a lot of overhead lighting is 277VAC.

Machine control voltages are either 120VAC or 24VDC. 24VDC is definitely preferred when it come to safety.

These comments of my are just a generalization but just about anything is possible if you buy a transformer.

 

[I_Automation]

These comments of my are just a generalization but just about anything is possible if you buy a transformer.

That brings to mind one customer of mine that had power problems with their 480V.


Finally had the utility send an technician to investigate and found the system was powered by pole transformers that were 495V, not 480V, plus the incoming power was wired Delta with one leg of the 495 grounded and the other 2 legs a full 495 to ground - no 277 that they presumed and had some things wired for in some machines.

 

[rupej]

600vac for Canada's auto industry. Obviously it will be plant specific.

I've also seen 600VAC as the main low voltage equipment supply in power plants that were built in the 60s / early 70s. It was common in that industry at the time but I'm not sure why or if it continued any later than that.

 

[JesperMP]

I am interpreting the last comments, as that 208V 3phase and 600V 3phase are not common, but also cannot be excluded totally. And there may be even more rare voltages.
Just for comparison, in the EU it is universally 400V, but some old plants may have some very special voltages. Power plants may be a special case even today, I have also experienced some odd voltages in power plants, but this machine is not for power plants.

If it is correct that 480V is more or less the standard (albeit with exceptions) I will probably end up with offering 480V per standard.
If this covers 90% of potential customers it will be acceptable.
Any other voltage will require a special price.