Dynamic Subspace

Tag: Generac

  • Plastic Point-of-Failure on a 60kWh Generac Whole-House Generator

    large Generac whole-house electrical generator on an elevated concrete pad, a house in the background

    As I wrote about last week, my parents’ Generac 60kWh whole-house generator died when we needed it most–at the beginning of a five day stretch without power after Hurricane Helene had passed through Georgia.

    For shorter power outages, the Generac generator has worked, but in this case, when it really mattered, it couldn’t fulfill its promise to supply power to the house for an extended period of time. This meant that we could not pump water from our well, all of our food in the refrigerator spoiled, the radon remediation system wasn’t running, the mobility assists for my folks couldn’t operate, and the air conditioner was out (and the temperatures were in the high 80s/low 90s).

    What specifically caused the Generac generator to quit running after about 48 hours was a busted plastic tensioner pulley that split in half as shown below.

    A belt tensioner applies tension to a larger sized belt so that the belt maintains the appropriate tension to transfer work from one pulley to another. If the belt is too loose, it won’t grab and rotate. If the belt is too tight, it might break. The tensioner pulley–along in this case with the right size spring–keeps the right amount of tension in the belt so that it rotates without breaking.

    The trouble that I have with this failure is how Generac made a couple of engineering choices that led to this failure. First, there is the overly complicated transfer of power from the engine (in the middle of the generator) to the opposite side of the radiator. They could have had the fan connected directly to the engine block or an assemblage connected to the engine block on the engine-side of the radiator so that the fan pushed air through the radiator instead of pulling it through as in the manufactured configuration. This would have reduced the number of parts–the extra pulleys, rods, bearings, and tensioner–and eliminated the tensioner pulley. Second, if their designers were adamant that a fan pulling instead of fan pushing configuration was better, they could have manufactured the tensioner pulley out of metal, and even better yet, used a standard tensioner pulley that was already mass produced for other applications. While this might have added some cost or reduced their profit by a very infinitesimal percentage of the cost of this generator (~$30k), it would have significantly reduced the likelihood of this part as being a possible point of failure.

    My folks have had this Generac generator long enough that its warranty lapsed in 2023. They have paid for regular maintenance–checks, oil changes, etc. It has run a test every two weeks since they purchased it. But, there was apparently no way to verify the tensioner pulley or a schedule to replace it.

    We were told by the repair crew that one other customer had the exact same problem–like ours, their generator had run after the area lost power and then their tensioner pulley had exploded in half just like ours.

    If you’re considering one of these for your house, be aware of the possible points of failure–there are many besides this pulley. A less complicated design seems better to me to reduce the chance of failure. With a complicated setup like this, having replacement parts on-hand is a must, which our local retailer did not have. With lesson learned, my folks now have a spare tensioner pulley and belt just in case.

  • Hurricane Helene

    a paved two lane road extending to the horizon at dusk, the sun illuminates the clouds above in a variety of colors

    Before Hurricane Helene was forecast, I had arranged to travel to Georgia to help my parents for two weeks after my dad got out of the hospital. By the time that I got off the Silver Meteor Amtrak train in Jesup, Hurricane Helene was just about to make landfall. Considering how well constructed our family homestead is combined with its 60kwh whole-house generator, we thought that we were well prepared for the storm. Of course, Helene’s global-warming-intensified onslaught exceeded expectations all along its path. We worked with neighbors to clear fallen oak trees from the dirt roads leading to our neck of the woods. Our generator kept us with power for the first two days of the power outage, but then, a woefully underclassed plastic tensioner pulley broke into two leaving the generator without its fan to pull air through its massive radiator and promptly shut down in the dead of night. My dad and I pulled it apart but without a replacement part, we were unable to get it going again. We went without power for three days. The food in the refrigerator spoiled and we would sit in the cars in shifts to keep cool. Cell phone service–Verizon and Google Fi–was completely down and then slowly restored in fits-and-starts. It goes without saying that I wasn’t able to write on my blog, but I did use the time to read Terry Pratchett’s The Colour of Magic (1983). A repair crew went through our property’s power line easement around 9pm on the third day and our power was restored. The generator repair company replaced the tensioner pulley two days later (more on this later). As I’m writing this, there are still thousands of folks in the Satilla ERMC service area without power. Crews are working non-stop to clear the lines and restore power. There are, of course, many more along the 500 mile stretch of devastation in much worse shape than us.