My company has promissed to sponsor some mini-roasters for coffee
laboratories for a project in Africa.  This type of equipment can be
purchased in Europe in two versions:  220 Volt and 380 Volt.   The
price is the same - or almost the same.

The 220 Volt version is by far the most frequently used in Europe, but
our contacts in Africa have asked for 380 Volt - not giving any
arguments.

What is the reason or advantage of using sometimes 380 Volt rather
than 220 Volt ?   (Might be something with safety or something with
efficiency or speed in starting/warming up or ....?)

It might well be that the Google researcher working on this question
knows the answer well. Fine. The answer does not necessarily have to
be in the traditional form of a list of website-references (although
they are most welcome).

The difference has to do more with local wiring then with performance 
of the appliance.

In the US, standard (household) outlets have one (hot) phase and neutral,
giving 110V. For industrial applications, particularly for large
induction motors, 3-phase outlet (giving 280V between phases) is used.

The two types of the outlet are shown here:
http://www.answers.com/topic/three-phase-electric-power

In other parts of the world, single phase outlet gives 220 and the
'industrial strength' comes to 380 Volts.

When the power (in Watts) is same, an  appliance which is 
basically a 'heater' will function the same.

If the room in which the unit is to be placed has industrial type wiring,
it would have both types of outlets for both 220V AND 380V. However, the 220V
intended for lights etc, may not have enough power, to accomodate a
large appliance. 
This would be a likely reason for ordering 380V, three phase, unit.

Hedgie

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Request for Answer Clarification by alsinger-ga on 15 Sep 2005 03:05 PDT

Dear Hedgie-ga,

Thanks for a quick and fine answer to my question.  
As your response seems to reflect more your personal knowledge than
just references to websites, I will allow myself to add a
supplement-question to which I guess you can respond within a few
minutes.

If one has an instrument/apparatus made for 380 Volt and wants to use
it in an area where there is 220 Volt only is it then possible/easy
can one then buy a small separate transformer/converter of some kind
and insert that next to the instrument  ?    Same question for the
other way around - from 220 to 380.

---

Clarification of Answer by hedgie-ga on 15 Sep 2005 05:32 PDT

Alsinger

Thank you for the kind words.

The answer is "Yes, but".

"But" means: Do not underestimate this. It is not too complicated,
 but there are some assumptions here:

1) We assume that the instrument  and outlet are for single phase AC current.
    (In the reference I gave you previously, there are pictures of single phase
     and 3 phase outlets)
2) The transformer must have enough capacity (measured in Watts) to handle
    the load, otherwise they  overheat or burn or (if they have this
    desirable safety feature)they  throw the built-in circuit breaker.
3) Transformers that are intended for use by consumers have plugs matching 
    the voltage so that it is physically impossible to have the wrong voltage 
    go to the appliance.
 
   Once you start using 'shape adaptors' to defeat this safety feature or  you
   hook up industrial transformers (which may arrive just with bare wires),
   you should know what you are doing. (Electricians are not that expensive
   and please do note the disclaimer at the bottom of this page).
   
4) You may not need a transformer (price and mass go up with power,
    about $1 per Watt). A voltage adaptor (not just shape adaptor) may do,
     depending on the type of load, and be cheaper.

5) If all conditions above are satisfied, then the same box can function as
   a step-up (220 to 380) or step-down (380 to 22v) transformer.
   
  
For more info, type the following into (google) search engine:

SEARCH TERMS :  Electrical Voltage, Plugs, and Adaptors

Hedgie

Thanks. The answer covers exactly my needs.

There are a few other things that can also be taken into
consideration.  The 380V power is a standard for three-phase power in
parts of Europe.  The 220V is a standard for three-phase power in the
US.

For more info on 3 phase power check out The 3 Phase Power Resource Site at:
http://www.3phasepower.org

Or read their section on 3 phase transformers:
http://www.3phasepower.org/3phasetransformers.htm

Provided the service has enough amps you could convert 220V power to
380V power with a step up transformer.  You can get a 220v to 380v
step up transformer from TEMCo Transformer at
http://www.temcotransformer.com/3-phase-transformers.html.

If the grinder requires 380v 3 phase power and the only power that you
have is 220v single phase power you can use a rotary phase/frequency
converter (http://www.hzfrequencyconverter.com) that will converter
the power from single phase to 3 phase and it will also transform the
voltage from 220v to 380v.

These are easy solutions, but these also require an electrician to wire them in. 

I wish you all the best with your new equipment setup.  :)

Also for a 220v 3 phase to 380v 3 phase converter you can speak with
some companies who are esperts at this, try speaking with the <a
href="http://www.usphaseconverterstandards.org">US Phase Converter
Standards Organization</a>.