Phil et al:
Wouldn't this method work ok if he did it with the primaries in series (vs.
parallel)? If they're out of phase, no voltage would appear, nor would
there be any damage. If in phase, you'd get your voltage. I would do this
with a 12 or 24 volt transformer supplying the voltage for the initial
test.
73
Bruce R. Knox W8GN
-----Original Message-----
From: Phil (VA3UX) [SMTP:phil@vaxxine.com]
Sent: Friday, August 18, 2000 12:41
To: Mark S Graalman
Cc: da_kang@hotmail.com; UNCRICHIE7@aol.com; amps@contesting.com
Subject: Re: [AMPS] Question About Correct Phase for 240V Transformer
Primary Windings ???
No ! This method has a 50% chance of working, and a 50% chance of damaging
(or destroying) the windings.
IF you just happen to connect the windings in the proper phase (polarity),
the voltage across the two primarys will be 120 volts and you'll have your
answer. It worked; no harm done.
IF you just happen to connect them with the wrong polarity (ie. one winding
"aiding" and one winding "opposing"), you'll create a dead short across the
primary (zero impedance with only winding resistance). Flux cancellation in
the core with incorrectly phased windings is the reason. There's a high
probability of damage if this occurs.
This method can be done if you understand the risk, AND if you install
current limiting series resistance and an ammeter first before applying
power.
Phil
At 11:23 AM 8/18/2000 -0400, Mark S Graalman wrote:
>
> Hook the primary windings up in parallel, if you
>have the phase wrong there will be no voltage
>output. Might be a good idea for safety sake to
>feed the primary with a low voltage transformer rather
>than full line voltage.
>
>
>Mark WB8JKR
>
>>
>> Hi Fellas, A question for you High Voltage Transformer Guru's. I
>> have an
>> unlabeled transformer. I have found the primary windings. This
>> transformer
>> can be powered by 120 or 240 volts. Heres the question. How can you
>> tell the
>> phase of the windings in order to properly set up for 240 operation.
>> I'm not
>> sure if this will help determine it but the pig tails of the
>> windings are
>> Brown/Black and the other is Blue/Yellow. As always any help would
>> be
>> greatly
>> appreciated... Thanks, Kurt, K3KL...
>>
>>
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