TRIAC switching problem in 3 pole Contactor

[anboli]

Hi to all,

I facing the Reset problem in the Contactor while de energizing the another Contactor.

I updated my triac switching circuit and flow of the signal from the controller to 3Phase AC Motors.

First i triggering the first contactor On by sending the value 1 to the output port to Buffer IC, Buffer Ic output pins also get high(5V). and it is sent to the ULN2803 to invert the voltage level, and it is inverted to 0V. output of the ULN is driven to MOC3021(2nd pin), so there is closed loop in the moc, it is triggered, from that TRIAC get activated and Phase signal is passed to the 230Vac Contactor to energize the coil. So the three phase Motor getting ON.

There is no problem in the sequence, when i facing this problem is. I switched the First Actuator always ON, Im triggering the Second Actuator for Repeated times, while im de energizing the second actuator, it releasing the First Actuator also, and it getting ON after the sequence start.

I dont know, where is the problem occured, whether in the TRIAC or In the AC Actuators(Contactors)..

Kindly help me.
Thanks in advance,
anboli.c

 

[FvM]

The circuit doesn't give any hint why this should happen, except for a far too low MOC3021 driver current of about 3 mA. Datasheet says trigger current can be as high as 15 mA. But actual threshold currents can be considerably lower, so this must not cause a problem. More likely you are sending wrong data to the output port.

 

[Venkadesh_M]

Is that any interlocks used for contactors??
Also check the uc and other outputs in reseted condition.....

 

[kabeer02]

I think he should check his micro controller very well