I used to run a freezer as a fermentation chamber or for cold crashing. No dramas while I was running it, but it died sometime before I moved into my new place. 3 minutes seems short of a compressor delay. Does it cycle much? Did it use much power? I don't see why it would put any more stress on it. I did have to start using desiccant in it though, as it did develop a bit of rust due to condensation. I'm on the lookout now for a deep freeze now to build a keezer setup. Did you use foam with the collar as well?