Hi :) I have a project for Science and we are supposed to try and keep ice frozen without using a freezer or cooler for 24 hours.I have to keep it in a 1 gallon milk carton and I can't put anything on the outside.The ice is goig to be a cup size piece.I was thinking of wrapping it in newspaper and put it on sandbut i'm not sureIn 2 weeks we're going to start the project and i hope to have some ideas soon!Thanks! :)
A full wave rectifier will likely do the trick for a motorBridge rectifiers are usually called for when you are working with more sensitive electronic equipment that needs less ripple in the line voltageUnless the motor is some type of stepper motor, a full wave rectifier should do.
aluminum foil also helps keep things cold/hot, but not for that longMaybe wrap it in foil and wrap the newspaper around it Does a Thermos count as a cooler? Those work well, too, and they make small ones now for soupI've also had leftover ice in styrofoam cups that stayed around overnightCan you put it into styrofoam and put that into the milk carton?
It will depend on the transformer's output firstly For full wave, hope you have the mid point in the secondary winding Bridge can be used in either case, but full wave requires three secondary leads I suggest a bridge because theoretically, efficiency is higher I assume that you have taken care of filter etc.
The pulsed DC coming out of the rectifier would generate heat in the motor and wear it excessivelyA capacitor will buffer the fluctuations, and result in smoother and more reliable operation.
Bridge and full wave rectifier do the same thingDepends whether you have secondary of your transformer with the middle point (in which case use full wave rectifier with two diodes) or if you don't have middle point use bridgeIn both cases you need capacitorYou wouldn't harm the DC motor by a bit ripple on your DC voltage (if you don't have large enough capacitor).
