I have a lamp module from Everspring for controlling my lights in my home. They work great as long as the voltage is stable and above 210Vac. The unit is rated on the label for 230Vac
I live in Indonesia and have a home power monitor and often see the voltage drop as low as 202Vac and this is where the units start to switch off and back on every few seconds. The speed of this gets faster as the voltage becomes lower. At around 208Vac is switches of and back on every 3-5 seconds.
I've opened one unit up and found that the supply is based on a capacitor drop type with a bridge rectifier, Zener diode and reservoir capacitor on the DC side. The reservoir capacitor is a 220uF 35V electrolytic.
I don't know much about this type of supply other than what I have read but I do know from research that they are not very good with varying input voltages and this is likely why I am seeing the effect of switching off and on as the output drops below the reset point of the microcontroller on the board.
I want to ask if anyone knows if I can simply put in a bigger reservoir capacitor, say something like 470uF 35V and if this will give better storage of the chopped DC wave form from the bridge rectifier? My concern is that this larger value may appear initially as a larger load on initial switch on of the unit although once power is on, it will always be on and the controlled output is done via the home automation system.
Is there any issues you can see in changing this cap to the 470uF or is the design probably optimised for the 220uF one currently fitted?
I have attached the underside of the PCB and you can see the bridge D and Zener Z1. R1 and R2 make up the resistor on the AC input with the capacitor underneath this. It's a high voltage X2 type rated for 275V