I am trying to remove the thermal fuse, thermostat, 75 ohm, and 150 ohm heating elements from this diagram:
This is the schematic for a popcorn machine that has two heating coils and a DC fan to blow over the coils: http://www.sweetmariascoffee.com/forum/viewtopic.php?f=14&t=5761. Basically I am trying to create a 115 V AC circuit that powers the 18 V DC motor through the rectifier bridge.
I imagine I need to replace the 75 ohm heating coil with some kind of resistor for this circuit to work correctly. Can I simply replace the 75 ohm heating coil with 75 ohms worth of resistors that I typically use in my DC only circuits?
Best Answer
NO! You buy a step-down transformer with a 12vac output that also isolates your fan from the AC line. You need to check the motor current rating and buy a transformer rated 150% of the motor current. Should not cost much. Connect the 12 VAC leads to the input of the rectifier bridge. The motor should be getting at least 16 VDC to 18 VDC.
Do not bypass the thermal fuse. It can be physically mounted to the transformer to kill the power if the transformer overheats-but there should be no reason for it to do so.
The thermostat and resistors can be discarded.