Need to build Phase detection Circuit in a 3 phase line

[naveen@zetakalyam.com]

Hi,

We need to design the phase detector circuit. We need to monitor the 3 phase line(230v ac,50Hz) for phase failure or phase change and send the status to microcontroller. Iam new to this. Please suggest me, how to build this circuit.

(I need to detect an OPEN Phase or phase to phase SHORT fault on 3 Phase supply input. If I detect any of following faults i need to send status signal to microcontroller.
OPEN Phase – A
OPEN Phase – B
OPEN Phase – C
Phase A to B Short
Phase B to C Short
Phase C to A Short )

Regards,
Naveen K

 

[schmitt trigger]

If you are new, SAFETY FIRST!
I would suggest to use a stepdown transformer from the line voltage to a safe voltage, let's say 6 volts. Then, via resistor dividers scale the voltage down to a level that will be within the range of your microcontroller.

 

[naveen@zetakalyam.com]

Thanks for your advice.
We need to step down the voltage for line with respect to neutral right?
Is any voltage difference between one phase to other phase with respect to neutral?
After scaling the voltage how we can check the phase? Please advice in detail.
We need to detect the phase faults(mentioned in previous post) and send the status to micro-controller.

Regards
Naveen K

 

[FvM]

We need to step down the voltage for line with respect to neutral right?

The answer depends on the expected load and under which conditions you want to detect the faults. If you define "Open phase" as "voltage against neutral < xx volts", then you need to measure against neutral. But in case of a three phase load, the voltage won't necessarily drop to zero.

Suitable detection methods depend on the intended information. Phase information or voltage above a certain threshold can be sensed through optocouplers, linear voltage measurement will require voltage dividers with differential amplifiers or transformers.

 

[naveen@zetakalyam.com]

Phase detection is required for "3 phase load" and other information are mentioned in previous post.Please advice in step by step. I will most appreciate if i got schematics or block diagram and related documents. It will very helpful for us.

Regards,
Naveen K