Jimi Henton, the local breeder from whom we got Aero, Jack, and Dash, brought me her dog grooming dryer some time back to see if I could figure out what was wrong with it. Carol has the exact same dryer, a Chris Christensen Kool Dry. It’s basically an SCR-controlled variable-speed fan in a box, putting out 114 CFM through a hose.
Jimi said it wasn’t blowing as much air as it used to, even after she cleaned the filter and made sure nothing else was gummed up with dog hair. It still blew, and the pot still varied the fan speed, but it wasn’t as loud and clearly didn’t have its out-of-the-box oomph. Worse, she’d had a new motor installed last year. The first one had gone for eleven years before dying; this seemed kind of premature.
I wanted to compare the two dryers to get a sense for how much air was being lost in Jimi’s. I have no way to measure airflow here, but sitting on the laundry room floor I noticed Jack’s little soccer ball, much reduced from its original size, but still round enough for my purposes. With only a little skill I managed to get the ball levitating over the nozzle, as any kid who’s bright enough to put a vacuum cleaner in reverse has done. On Carol’s dryer, the ball wobbled between 18″ and 24″ above the nozzle. On Jimi’s, it was maybe 4″.
So there was work to do, somewhere. Upon opening the dryer up, at least one problem was obvious: The 1,025 watt AC motor was wired to the speed control with #24 telephone wire, and too much of it. (You know, the stuff with the two-color, bands-on-solid insulation.) Close inspection showed two cold solder joints, coincidentally (heh) where the #24 wire hit the speed control pot. The plastic insulation on the phone wire was blackened with heat. The dryer slowly was cooking itself from the resistance of all that skinny wire. No need for a fork; it was done.
Jimi had ordered the motor from the manufacturer and then had somebody local put it into the dryer. She called him an amateur. No. I’m an amateur, with a callsign to prove it. I do electronics because I love it. Whoever installed this motor was…an idiot.
All fixed now, using some #14 stranded wire and soldering skills I learned when I was eleven. Both dryers now loft the soccer ball two feet hgh. Ohm’s Law is a bitch, dude. Please go back to sharpening scissors.
