Working with Potentiometer

The PAD controller turned on the last time but the thermal coupler did not work. The cause was because the wires were backward and after reversing them, it worked. Need to see if the heating element will work today.

We learned about what a potentiometer was today. It controls the amount of voltage. This will be used to control the speed of the auger which pushes the pellets into the heating element. At full speed, it will go at 24 volts. Basically less speed correlates with less volts being done. As the knob of the potentiometer turns, the resistance increases which leads to the less speed or volts. It works by a center pin that is connected to a brush and then that brush contacts the loops so as the brush moves, the wire essentially becomes longer and that wire is wrapped around ceramic.

V = IR

V - Voltage (volts)

I - Current (amps)

R - Resistance (ohm's)

• When the V increases, the I or R increases while the other decreases

• The I refers to the motor speed in our case

In order to find voltage, we need to put wire through multimeter. We need to figure out if we want to put a new wire coming out of the multimeter or just put the same wire.We are using the voltage power supply as a prototype. It is similar to the voltage regulator. We gave the motor DC voltage and found that 15 volts was too slow while 30 volts was too fast. 24 volts was ideal.24V = IRI = 24/VariableA slower motor is better because it causes the pellets to heat up thoroughly (basically more time in heating element)A faster motor may cause not got enough heating because of the less time that would be spent in the heating elementThe multimeter showed an increase of rampage when the pellets were in because of the resistance they caused.We started to work on what screw we needed to use to put the parts of the machine together (the 3d printed parts). The flush straight, perfect screw that was used previously was 0.628 inches, so we cut down a longer screw to that measurement. But, the cut down screw did not fit because it was too short due to it having a rounded head opposed to the previous one which had really flat head.We need to change the the thermal coupler for the next meeting.