Mains voltage in US

[kallileo]

Our company manufactures pasteurizers and we want to make a US version.
The standard european version uses 230V for the control circuit and 400V for the 3ph heater.
Now we want to make a sample 120V/208V, 60Hz version.
Live and neutral will be used to get 120V and the voltage between 2 phases is 208V.
Is it correct?

I have also seen that in some areas there also 220V, 60Hz single phase voltage present.

 

[itsmoked]

There is a lot of 240V 2 and 3ph also. The older or more industrial an area the more likely (and lucky) 240V will exist instead of 208. You may need to offer both as the power difference is pretty substantial between 208 and 240V run thru the same heating elements.

Lots of dairies are rural and will have 240 whereas new development and light industry areas would have the 208V. I could see milk processors in urban areas being in heavy industry areas because of the truck traffic delivering the milk so that would point to 240V also.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The standard single phase voltage is 240 Volts, center tapped to provide 120/240 Volts.
240 Volt delta systems often have one of the phases center tapped (with the center tap grounded) to provide the standard 120/240 Volt single phase as well as 240 Volt three phase. One phase then has a higher voltage to ground than the other two and is called the "wild" phase. The wild phase is used only for three phase loads.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jraef]

The main point is, there is no monolithic standard that applies to all areas of the US with regard to 3 phase power. If the power requirement is low, you may want to consider sticking to single phase 120/240V, that is as close to universal as we get. Then what you can look into is simply re-rating it for 208V single phase if that is what they have, acknowledging to the end user that if connected to 208V, the heater (assuming resistive) will not get as hot and may take longer to accomplish the task.

"Will work for (the memory of) salami"

 

[kallileo]

It's so much easier here in Europe.
The main concern is the heater.
The standard heater is resistive 12KW wired in star connection for 3ph 400V.
Practicaly they can be considered as 3 single phase heating elements of 4KW each.

 

[waross]

You may consider a version rated for 208/240 Volts. Use enough 240 Volt elements for adequate heating at 208 Volts. The unit will, of course, heat faster on 240 Volts.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LionelHutz]

You could supply the 4kW x 3 heaters sized and connected to work on 240VAC/3-phase. Then, add another 1kW x 3 heater elements connected to terminal blocks so the customer/installer can add them into the circuit for operation on 208VAC/3-phase.

 

[waross]

Let's see;
A 4 kW heater on 208 Volts will be about 11 Ohms.
A 4 kW heater on 240 Volts will be about 14.4 Ohms.
How about 11 Ohm heaters in series with 4.4 Ohm heaters.
The unit could then be connected for either 208V or 240 V.
A 208:240 Volt transformer connected across 208 Volt taps will give 240 Volts for control, regardless of the supply voltage.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[kallileo]

We want to make the machine as simple as possible so I want to avoid additional transformers.
We are considering the 208/240V version for both heater and control circuit.
The heating will be slightly slower when connected to 208V but it's will not be a problem.
We can't find a circulator pump at 110V from any supplier here so we will probably have to get 240V version.
I also have few contactors and coils.
In case I decide no to use 110V for the control circuit but 208/240V, which seems more reasonable and simple, can the same contactor be used for both 208/240V or the coil is going to fail?

 

[waross]

Old school the answer is yes. For many years 230 Volt motor control equipment has been used successfully on 208 Volt systems (240 Volts is the supply standard, 230 is the utilization voltage for motors and associated controls). I'm not sure about IEC equipment.
Motors rated at 208/230:460 Volts are available.


Bill
--------------------
"Why not the best?"
Jimmy Carter