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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 -----
From: Ralph G
Vogan
Sent: Saturday, February 19, 2005 12:19 PM
Subject: Re: [SPAM] Re: (ET) Charger repair. 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. Ralph V
ralphgv centurytel net ET Web page http://ralphgv.tripod.com/ 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
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