under over voltage shutdown circuit

[gupta]

i want to connect an over under voltage shut down circuit at 3-phase input mains.
input power supply specs are following:
400V 50Hz delta .
have you any circuit or web link for this purpose.
thanks

 

[IanP]

You can try this method:
connect a small 220/12 (or less) transformer between each phase and Neutral (I asume you have access to N or E, in isolated circuits the primary should be rated for 400V and connected betwee phases). If you want to monitor each phase separately you will need 3 circuits with OR function at the final stage.
Rectify the voltage using a bridge full or single diode + smoothing capacitor and use "window" comparator build of two comparators for LOW and HIGH limits.
Output from this "window" comparator will be used to switch a 3-phase contactor (you will need current booster such as blt or mosfet transistor to control the contactor)........to perform the shut-down operation.

 

[ta2ctp]

Hello,
You must look or search the site TCA965 chip application. (Window discriminator
chip)
Sincerely
ta2ctp