I have a similar situation i have an 240vac to 18vac transformer but i need 12vac for the Christmas tree fiber optic rotating motor and light. 5W 12vac required. How can i lower from 18vac to 12vac?
Considering the complexity of circuitry to reduce the voltage and the time/effort to implement, I suggest that the more prudent solution is to simply buy another transformer. A 5W wall-wart transformer should not be very expensive and would be a "clean" solution.I have a similar situation i have an 240vac to 18vac transformer but i need 12vac for the Christmas tree fiber optic rotating motor and light. 5W 12vac required. How can i lower from 18vac to 12vac?
That would lower the RMS value of the voltage, but not necessarily the peak value. Not sure how the motor would respond, but depending on the LED regulator circuit it might have high enough peaks to cause some problems.You can use a light dimmer on the Primary side to lower the output voltage,
You basically need Phase Angle Firing with current limit to operate into a transformer. Before my time at work, some temperature controllers worked operated into a Variac and some did not. I wired them all with current limit, used 25 A I2t controllers and added a load fuse.Full disclosure, I've never looked at a power transformer secondary with a scope when the primary was driven through a TRIAC dimmer. Hmmm...