I used an external adjusting buck boost transformer for a project.
My problem was that the HV transformer would give too much voltage.
This is easy to correct by lowering the mains voltage input.
I tried to use an isolation transformer where some windings were removed
from the secondary.
This was no sucess, the HV was wery soft under load.
A variac may be used, but since the required voltage reduction was fixed, I
figured out that
this could be done by connecting the secondary of a transformer in series
with the primary.
Input was the ordinary primary. Output was the primary + secondary winding.
The secondary was 24v 10 amps. Connecting this with inverse phase produced
230-24=206v.
The HV regulation was much improved with this configuration.
Increasing the input to your transformer is not recomended unless it can
handle this.
In cases of low mains voltage under load, buck-boosting a few volts will
help output.
I assume the secondary of the buck-booster transformer
should have the current capacity matching load from the transformer it is
boosting.
It should not be dangerous to connect two transformers as described.
An interesting possibility:
If the booster is soft and is used in lowering the voltage, low voltage
under load will increase the supply and stabilize the input to the boosted
transformer. This is about phase relation, so a resistors can probably not
be used to "soften" the booster.
Helge / LA6MV
-----Original Message-----
From: carl seyersdahl [mailto:carlseye@tampabay.rr.com]
Sent: 5. september 2003 14:02
To: Amps@contesting.com
Subject: [Amps] buck-boost (b-b)
In using an "external" transformer secondary (maybe 12vac) to raise or
lower the line voltage in subject manner, what is the current requirement of
the added winding?? will it be the same as the total current , as it seems ,
or just the additional current ( or power) needed to raise (or lower) the
line voltage.?? (power)
I'm building a line voltage adjustment unit and altho my transformer can
easily handle 10 amps I'm still curious about this.!!
(it's the little things that make me curious )
carl / kz5ca
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