I hadn't thought about using
equipment on 50 hz vs. 60 hz in years. There are a couple of things that
you would need to change or look into. Since the charger is a
ferro-resonant circuit, you shouldcjange the capacitor. The resonant frequency
is proportionate to one over the square root of the LC product, where L
is the inductance of the transformer and C is resonant tuning capacitance.
This means that the capacitance for 50 hz would be would the 60 hz
capacitance times the square of the frequency ratio, which is 3600/2500 =
1.44.
The other consideration is that the
losses in the transformer and the magnetic flux density produced are dependent
on the frequency. This generally means that there will probably be more loss,
and thus more heating, at 50 hz. This may require derating the power you can
get from it without overheating, etc.
The specifications of the charger
should really contain an allowable operating frequency range. I last had to
deal with this problem in the '50's, when I was designing equipment for
operation in Australia and New Zealand. Most of the equipment then was rated
for 50-60 hz. An inter5esting problem came up in New Zealand. Most of the
power there was generated by hydroelectric plants. They were having water
shortages at that time. They didn't have enough water available to run the
turbines fast enough to generate 50 hz. The frequency often was several hz
below 50, which was getting pretty marginal for operation. I don't remember
that anything failed as a result of this, however.
Good luck with it.
Herb Crary
Boulder CO
----- Original Message -----
Sent: Saturday, February 19, 2005 12:19 PM
Subject: Re: [SPAM] Re: (ET) Charger repair.
I think the ET charger might work ok, but you may have to
change the capacitor or add a resistor in series with it
to tune it to
50Hz. A 1000va step down transformer would only give you about 8.4
amps at 120 volts. I think you will need more then that for bulk
charging.
Markus
Lorch wrote:
Wow Steve,
I learned something new today. Thanks for that link.
Actually I was hoping to continue using my elec-trak charger as
a bulk charger when back in Germany with a 1000VA step-down
transformer. However we have a 50Hz AC frequency there
and from the description of the ferroresonant transformer it
looks like this may be a problem as it is probably tuned to
the 60Hz used in north america.
Do you have any thoughts on how complicated it may be to
adapt the charger, I had hoped that in the long run I could
adapt/rewind the primary winding to the 230V used in Europe
but I would probably also have to do something with the
compensation winding which may make the whole thing too
much of an effort. I guess I'll then be better of with
using a more modern switching charger or get me a standard
transformer. Any suggestions?
Markus
_______________________________________________
Elec-trak mailing
list
Elec-trak cosmos phy tufts edu
https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak