Inductive kickback sounds scary so I have been trying to and possibly failing to understand the theory behind it and how to counter it. I have at least done my best to prevent the Micronel Centrifugal Fan I have been using for my table tennis project from frying my relays by adding a kickback diode. Initially the wiring threw me for a loop until I found that for some odd reason the red cable is negative and black positive. Luckily nothing got fried in the process. Measuring the voltage spikes before I added the diode and after shows a definitive difference. There is no measurable voltage spike with the diode attached. Fingers crossed that I got this right.