Transducers

[bejoyengineer]

Hello
If we have a WATT transducer and at the time of testing the transducer using a freja, and if we apply voltage for R phase=66.4 & phase angle=0;Y phase=66.4 & phase angle=120 and B phase=66.4 & phase angle=240 and if we apply current for R phase=3 Amps & phase angle=0;Y phase=3 Amps & phase angle=120 and B phase=3 Amps & phase angle=240 we get the transducer output value as positive and if we require a negative value for the output WATT transducer ,we apply zero degree for voltage phase angle and current phase angle would be 180 degree . so if we have to test for a MVAR transducer - what phase angle should we apply -so that we get a positive and negative value at the out put of the transducer?

 

[Cold Fusion]

First thing I would do is get the book on the particular transducer you have.

Second thing is to read the book.:roll:

cf

 

[GeorgeB]

Hello
If ... we get the transducer output value as positive and if we require a negative value for the output WATT transducer ... what phase angle should we apply so that we get a positive and negative value at the out put of the transducer?

First, I agree with Cold Fusion.

The concept of negative watts confuses me UNLESS you are defining it based on whether you are supplying power vs using power. I've never used a bidirectional device for anything but SWR in RF circuits.

Give a little more information after you have investigated the manufacturer's documentation.

 

[djohns6]

When you rolled your current and potential out of phase , you should have seen a Var output .

 

[SG-1]

90 degrees lead & lag will give you maximum VARS. Where as 0 & 180 degrees gave you the maximum WATTS.

 

[bejoyengineer]

Hello,
well the below two answers had my point cleared

"When you rolled your current and potential out of phase , you should have seen a Var output . "
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"90 degrees lead & lag will give you maximum VARS. Where as 0 & 180 degrees gave you the maximum WATTS."
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so now i can say that if we apply 90 degrees and 270 degrees - we will get the maximum VARS, but does this vary for transducers placed in a Line bay and those transducers placed in transformer bays or to be more clear--- do we have to apply 270 degree for the line bay's transducer so that we get a positive output from the transducer and 90 degree for getting a negative output from the transducer and does this have to be the other way when it comes to the transducer placed at the transformer bay?

 

[SG-1]

Nearly all transducers I have functionally tested had their schematic diagram on the transducer body. There will be no difference in the connections between locations.

For instance, if point one on the transducer is calling for the positive electrical polarity from the A-phase CT, then that is what goes there. If point 5 is calling for the positive electrical polarity of C-phase voltage, then that is what it gets. When all the PT & CT inputs are connected with respect to the electrical polarity the transducer will faithfully read the watts & vars. Unless an external power source is required.