AC Watch Winder Controller Board

While most of the watch winder circuit boards are powered by both AC Mains and DC a.k.a. Battery Power, some circuit boards are powered by only AC.


In this case, a few changes are needed for the circuit to work. In general,


Power Transformer
To step down the voltage from Mains Voltage, 120VAC or 230VAC, to the general required working voltage, a transformer is required. This step-down transformer (the big black thingy on the right side of the board) is important when the manufacturer assembles it to the housing as it poses a high potential on the winder housing if not properly grounded and will electrocute the user. It’s then passed through a Rectifier which converts Alternating Current (AC) to Direct Current (DC).


Voltage Regulator
Once the voltage has been reduced and rectified to a workable DC voltage, it goes through a voltage regulator, basically the 7812 which ensures stable DC voltage throughout the circuit. I’ve already removed the voltage regulator from this board as it was defective.


But since the motor used here is an AC type, the DC signal from this IC cannot directly control the ON-OFF times of the motor. It has to trigger a Triac, which usually does a good job in AC circuits.


Triac
A Triac is a combination of a transistor and diodes, Triode for AC circuits. So it was named TRIAC. This Triac acts like a switch and will allow current to pass through to the AC motor. The Control IC aided by the resistors will activate this switch at the “programmed” ON-time and “shuts down” for the duration of the OFF-time.


Terminal Block
The blue thingy seen in the picture is a terminal block where a pair is used as AC input while the other pair for the AC motor wires.


AC Synchronous Motors
The AC Synchronous motor here is a single-phase type and works on alternating current. It will rotate at a fixed speed independent of the load. This means, the same RPM throughout low or high loads.

The other components are basically for smoothing ripples, current limiting and are too technical to explain. I hope you get the general idea about an AC Winder circuit. This circuit board is placed inside a metal chassis forming the base of the winder.

I would like to apologize if I do not wish to entertain request for this circuit as it is proprietary to a Watch Winder company. All the component values have been changed in the picture. It only serves to give you an idea that there are control circuits which rotate AC motors.

Labels: watch winder circuit