parthiban
Newbie level 6
Hi, i have a microcontroller based three phase preventer to protect two phase running loads and which is old model and don't have display and keypad, now i like update that preventer to showing all parameter like phase and line voltage, current, frequency, phase sequence fault, over voltage and current. low current(dry run) and low voltage.
For star or 4 wire model i made a circuit as 230Vac - 12Vac(step down transformer) - fullwave rectifier - 7805, then finally i got 5v for controller circuits and i tied neutral wire to dc ground as common to measure a property of Ac mains.
But in the case of delta or 3 wire model circuit like 440Vac - 12Vac - fullwave rectifier - 7805 , then finally i got 5v for controller circuits, but there is no neutral wire to create common path for measure. so i how do i measure voltage and current.
Voltage measurement done by resistive divider network, current measured by CT.
For star or 4 wire model i made a circuit as 230Vac - 12Vac(step down transformer) - fullwave rectifier - 7805, then finally i got 5v for controller circuits and i tied neutral wire to dc ground as common to measure a property of Ac mains.
But in the case of delta or 3 wire model circuit like 440Vac - 12Vac - fullwave rectifier - 7805 , then finally i got 5v for controller circuits, but there is no neutral wire to create common path for measure. so i how do i measure voltage and current.
Voltage measurement done by resistive divider network, current measured by CT.