The circuit is shown in the figure. The single chip microcomputer IO drives the triac BAT16 through the optocoupler MOC3041, and then BAT16 controls the 3-phase AC contactor. It is found that when the single chip microcomputer controls the AC contactor, it can be closed normally in most cases, but Sometimes the AC contactor is disconnected immediately after being closed. After disconnection, Ma Xiang is closed, and the frequency is so fast. After a few seconds, the resistance of 360 ohms ( R19) J will spark and burn, what is the problem?
Nolan 发表于 August 3, 2020
The input current of the optocoupler (about 6mA) is too small, resulting in unreliable trigger output.
For MOC3041, the current should be 15mA. Try to reduce the resistance R46, 130R.
Melanie 发表于 August 3, 2020
It is estimated that the frequency of the AC contactor's pull-in core disconnection is too fast, resulting in a larger current.
Brody 发表于 August 3, 2020
Do the positions of R22 and c37 need to be reversed?
