Data Logging Current Usage - CT''s and shunts
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Posts: 46,084
Current transformers are great, but since it's a "transformer" only works
with AC, not DC. Still, I can remember ammeters from old cars that used a
single insulated wire lead that passed though a little clamp on the back to
measure generator battery charge. This wasn't a series resistor thing.... it
used a fully insulated lead from the genny that had no actual copper contact
to the meter. Direct magnetic field sensing, perhaps? Will a Hall Effects
sensor make any sort of linear output when in close proximity to an
insulated wire carrying direct current?
Just a thought....
Mike
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, July 28, 2003 10:50 AM
Subject: [noparse][[/noparse]basicstamps] Re: Data Logging Current Usage - CT's and shunts
> Jameco has one of the coil wrapped in an enclosure style. you pass
> your wire thru it for current measurement. It's only a couple bucks,
> but I don't think it will got to 50 amps.
>
> In the commercial industry, they are called Current Transformer or
> CT's. used on power lines to monitor current.
>
> For your application, the Analogue to Digital is where your accuracy
> will lie. the current sensing units will have the ablility to output
> a pretty accurate signal.
>
> and if you do some small research on transformers and wire wrapping,
> you can easily make your own.
>
> on another note, maybe should be another thread......
>
> I have an application that charges a capacitor, then as the cap
> begins to discharge, I want to monitor that and control the charging
> MOSFET.
>
> I was looking at a shunt, but have found little in the way of
> information. 20 amps, 70 volts, and as low a resistance as possible
> that offers a signal to the comparitor.
>
> The idea is that the voltage passing will have some resistance and
> one can monitor the voltage across the resistor.
>
> any ideas on where to get a shunt or how to make one ?
>
> Dave
>
>
>
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Body of the message will be ignored.
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>
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>
>
with AC, not DC. Still, I can remember ammeters from old cars that used a
single insulated wire lead that passed though a little clamp on the back to
measure generator battery charge. This wasn't a series resistor thing.... it
used a fully insulated lead from the genny that had no actual copper contact
to the meter. Direct magnetic field sensing, perhaps? Will a Hall Effects
sensor make any sort of linear output when in close proximity to an
insulated wire carrying direct current?
Just a thought....
Mike
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, July 28, 2003 10:50 AM
Subject: [noparse][[/noparse]basicstamps] Re: Data Logging Current Usage - CT's and shunts
> Jameco has one of the coil wrapped in an enclosure style. you pass
> your wire thru it for current measurement. It's only a couple bucks,
> but I don't think it will got to 50 amps.
>
> In the commercial industry, they are called Current Transformer or
> CT's. used on power lines to monitor current.
>
> For your application, the Analogue to Digital is where your accuracy
> will lie. the current sensing units will have the ablility to output
> a pretty accurate signal.
>
> and if you do some small research on transformers and wire wrapping,
> you can easily make your own.
>
> on another note, maybe should be another thread......
>
> I have an application that charges a capacitor, then as the cap
> begins to discharge, I want to monitor that and control the charging
> MOSFET.
>
> I was looking at a shunt, but have found little in the way of
> information. 20 amps, 70 volts, and as low a resistance as possible
> that offers a signal to the comparitor.
>
> The idea is that the voltage passing will have some resistance and
> one can monitor the voltage across the resistor.
>
> any ideas on where to get a shunt or how to make one ?
>
> Dave
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>