Hi Martin!

> First thanks again for the help.  My research to date regarding
> differences between 50 Hz and 60 Hz machines, seems to indicate no
> difference between the number of poles.  The motor will have either
> 2,4,or 6 poles and that will determine rotation speed at either of the
> two frequencies.

Yes. A 4 pole machine, for example, will have to run near 1800 RPM at 
60Hz and near 1500 RPM at 50Hz.

 > What I haven't yet determined is the effect on
> voltage.  I suspect that 50 Hz machines may be wound differently. 

A 50Hz machine needs more turns per Volt for a given magnetic 
cross-section.   So, for a given size of the iron parts, you need more 
turns, which forces you to use a thinner wire, reducing the current 
output. As a result, 50Hz machines are slightly larger for a given power.

You may know that planes and some ships often use 400Hz instead of 50 or 
60. That's done mainly because it allows to significantly shrink the 
generators, motors and transformers!

> If
> I take a 60 Hz, 230 V motor and spin it slower to get 50 Hz, I will
> probably also get a lower voltage.

At a constant excitation, yes.

 >  Not good of I want 230V, although
> I've read that I may be able to up the voltage by changing the
> capacitance.  Will have to delve into this more.

Which means increasing the excitation. That should be possible, unless 
you get into the range where you saturate the iron!

> Of course I could just buy a 50 Hz machine in Chile, but I can find
> good prices on new/surplus motors here on eBay.  For example, I can
> get a 25hp, 3 phase, industrial built new motor here for $100. 

Well, at THAT price, I don't think anything in Chile can compete! Buy it 
there, bring it, and do whatever is necessary to get it running, even if 
that means running your system at 60Hz. That shouldn't be crazy. Most 
appliances will run as well from 60Hz as they do from 50. Just some 
things, like 50Hz motors. Might not like it much... And for fluorescent 
tubes, you would have to use electronic ballasts, which are not 
frequency-sensitive, while traditional ballasts are.

> I can
> also get inverter duty motors here.  I don't have the foggiest of
> where to begin to find similar stuff in Chile.

Nor have I... Inverter motors? In Chile you can find all the common 
things, but specialized things have to be imported on request, or better 
you import them yourself.

 > Of course there are
> shipping costs involved, but I'm going to ship a bunch of stuff down
> in a container anyway.  

Then bring everything you think you will need, as that will spare you 
the hassle of trying to find stuff in a place you don't know!

By the way, if you need info about any issues of settling in Chile, I 
can put you in contact with a friend who is from the USA and settled in 
Chile about 2 years ago.

Cheers,
Manfred.


--------------------------
Visit my hobby homepage!
http://ludens.cl
--------------------------





------------------------ Yahoo! Groups Sponsor --------------------~--> 
Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page
http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/FGYolB/TM
--------------------------------------------------------------------~-> 

Does your company feature in the microhydro business directory at 
http://microhydropower.net/directory ? If not, please register free of charge 
and be exposed to the microhydro community world wide!

NOTE: The advertisements in this email are added by Yahoogroups who provides us 
with free email group services. The microhydro-group does not endorse products 
or support the advertisements in any way. 

More information on micro hydropower at http://microhydropower.net

To unsubscribe: send empty message to [EMAIL PROTECTED] 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/microhydro/

<*> To unsubscribe from this group, send an email to:
    [EMAIL PROTECTED]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/
 


Reply via email to