Re: Dumb "current transformer" questions

If I understand you corrrectly, you mean to parallel a load resistor with a
rectified meter. That certainly should be good as long as the resistor value
is low enough and it does not get disconnected. The resistor should take the
majority of the secondary current.
Don Young
"Ignoramus19198" <ignoramus19198@xxxxxxxxxxxxxxxxxxxx> wrote in message
news:fX6of.5535$Di.1482@xxxxxxxxxxxxxxxxxxxxxxxx
> On Wed, 14 Dec 2005 22:41:09 -0600, Don Young <notme@xxxxxxxxxxxx> wrote:
>> Keep in mind that the burden (load) on a current transformer increases as
>> the secondary load resistance increases.
>
> Yes.
>
>> Keep the resistance as low as possible and still develop adequate
>> measurable output.
>
> I agree.
>
>> I have never seen current transformers without a
>> either a resistor or coil directly across the secondary, but it
>> might be done. I think that unloading the secondary, even
>> momentarily until diodes are forward biased, is not a very good
>> idea. Depending on diodes and or long leads to a meter seems
>> unnecessarily risky. An unloaded secondary can develop destructively
>> high voltages across the secondary and high voltage drops in the
>> primary along with excessive heating of the transformer. Ideally,
>> current transformers should have zero volts across both primary and
>> secondary. Don Young Don Young "Ignoramus19198"
>
>
> I think that what I could easily do, is parallel a higher resistance
> diode so that it is parallel to the rectifier bridge. Then, while the
> diodes in the bridge are recovering, this higher resistor would
> momentarily take on current. (which is low since we are talking about
> a transition of sinewave AC)
>
> i
>
>> <ignoramus19198@xxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:WYXnf.31886$xM5.18240@xxxxxxxxxxxxxxxxxxxxxxxx >> On Wed, 14
>> Dec 2005 08:39:24 -0800, Jim Stewart <jstewart@xxxxxxxxxxx> >>
>> wrote: >>> Nick Müller wrote: >>>> Jim Stewart
>> <jstewart@xxxxxxxxxxx> wrote:
>>>>>
>>>>>
>>>>>>Yes, assuming that you haven't exceeded the primary
>>>>>>or secondary current ratings for the transformer.
>>>>>
>>>>>
>>>>> Wouldn't a hall sensor do a better job?
>>>>> I mean with all the square wave and changing frequency a current
>>>>> transformer seems to be not the best choice.
>>>>> And if he is in DC ...
>>>>
>>>> Well, since it is Iggy that posted the question,
>>>> he probably has a big bag of surplus CT's that
>>>> he bought for $.50 (:
>>>
>>> No, I only have very few CTs, I need to use them for my phase
>>> converter measurements.
>>>
>>> i
>>>
>>
>>
>
>
> --
>


.

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