Mithun_K_Das
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I have made several 3 phase servo voltage stabilizers in last few months. Each one with same design working fine. Only one unit is having unexpected problem. Need suggestion if I'm missing anything to check.
This is the common circuit for each one. In our 3 phase servo voltage stabilizer we are using 3 individual servo voltage stabilizer and combined it is working as 3 phase SVS. When we test each one we check supplying single phase to single set of voltage stabilizer. If 3 sets works ok then we supply 3 phase supply.
The problem with this one is, when each phase is checked individually, it works fine. No inrush current, no MCCB tripping. Even if we short 3 inputs and supply single phase line it works fine too. But if we supply 3 phase line the 63A 3 phase MCCB trips with spark. Even 100A one trips. But once it is powered up manually with MCCB bypass, it is taking only 0.6A in each phase without any load. Which is same as other ones.
My question is, what may happen here? Am I missing something? I checked line to body conductivity for leakage. No, no leakage. checked for short, no short found.
Notes:
Input voltage range: 220V to 230V.
Have 3 phase line with Neutral. Taking Neutral to any one phase for single phase line.
With all 3 lines, it is working as 3 phase.
Phase to Phase voltage: 380V to 400V
Voltage stabilizer capacity is all same, 40KVA.
Same auto transformer, Same connection.
Same control circuit.
Same Casing & fittings.
Thanks in advance.
This is the common circuit for each one. In our 3 phase servo voltage stabilizer we are using 3 individual servo voltage stabilizer and combined it is working as 3 phase SVS. When we test each one we check supplying single phase to single set of voltage stabilizer. If 3 sets works ok then we supply 3 phase supply.
The problem with this one is, when each phase is checked individually, it works fine. No inrush current, no MCCB tripping. Even if we short 3 inputs and supply single phase line it works fine too. But if we supply 3 phase line the 63A 3 phase MCCB trips with spark. Even 100A one trips. But once it is powered up manually with MCCB bypass, it is taking only 0.6A in each phase without any load. Which is same as other ones.
My question is, what may happen here? Am I missing something? I checked line to body conductivity for leakage. No, no leakage. checked for short, no short found.
Notes:
Input voltage range: 220V to 230V.
Have 3 phase line with Neutral. Taking Neutral to any one phase for single phase line.
With all 3 lines, it is working as 3 phase.
Phase to Phase voltage: 380V to 400V
Voltage stabilizer capacity is all same, 40KVA.
Same auto transformer, Same connection.
Same control circuit.
Same Casing & fittings.
Thanks in advance.