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Topic: Current transducer AS-10x series doubts (Read 761 times)previous topic - next topic

fabpolli

Jul 04, 2012, 05:39 pm
Hi all,
I need to detect the current used by a washing machine powered with a 230 V, and after trying a type of sensor with no results I would use one of these current transducers:
http://docs-europe.electrocomponents.com/webdocs/008f/0900766b8008f208.pdf
In detail, an AS-100 or AS-104 but looking datasheet or on the net I only found this site:
http://dcc-mueller.de/wire4dcc/sensor_e.htm
But I do not know if the circuit in Figure 4 can be used directly or whether it should be placed downstream of the circuit in Figure 1 or 2.
Attempting to calculate the shunt resistor for the sensor AS-104 according to the datasheet:
VMS = Rt x Is x (1/2F)
Rt (Ohms) = Recommended terminating reisstance
Is (A) = Secondary Current
F (Hz) = Frequency
in the table shows a value of 1500 for the VMS component AS-104, and a value of Is 30mA then the calculations that I made I put a 200 ohm resistor but I'm not sure I understood correctly the Datasheet:
1500 = Rt x 0.3 x (1/2 * 50)
Rt = 1500 / 0.3 x 25 = 1500 / 7.5 = 200

I thank in advance those who will help me
Hello

MarkT

#1
Jul 04, 2012, 06:56 pm
The VmS spec is the voltage-time impulse it can take without saturating I think - nothing to do with normal use on a sinusoidal mains waveform AFAICT.

The secondary current is N times smaller than the primary current (where N is the turns ratio), and the output voltage is this secondary current times the burden resistance.   So the output voltage = IR/N

Do not operate without a burden resistor across the secondary.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

fabpolli

#2
Jul 05, 2012, 09:13 am
Hello, First, thanks for clearing up the component parameters. I now believe I understand, the resistance to be used is already indicated in the datasheet, for example for the model 104 if I use a resistance of 500 ohms produces 1.0V for each amperes used over the line monitored. Increasing or decreasing this resistance,  output will change linearly. So I think the diagram in Figure 4 can be used directly to apply the sensor to an input pin of Arduino, right?
Thank you so much

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