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I have a friend (and client) who owns a take-out restaurant. Today when I stopped by he presented me with two food processors. These are the commercial sized machines with the half or 3/4 HP motor, that can shred things very rapidly. Also, they hhave an abundance of safety features because they could turn a hand into hamburger in seconds. So there is a whole lot that could fail and keep them from running. And the newer one, not even two years old, simply quit.
So I was asked to try to repair it, before he had to spend a few hundred on a replacement. OK, I would give fixing it a try.
But with all of those safety mechanisms, locating the problem would be a challenge, because any one of the systems could be just a bit off and keep it silent. AND it was vital to not impair any safety system .
So with a fair amount of misgiving I opened the bottom cover, which was quite adequately secured. two minutes of examnation revealed an unexpected failure which had no probable cause. It was not one of the safety interlock switches.
The motor is a highstarting torque capacitor induction motor that in addition to the large capacitor also uses a starter relay to open the start-winding once the motor approaches the rated speed. The wires connecting that motor used quarter inch push-on FASTON style terminals. One of those push-on connectors had failed, and with a whole lot of arcing, had evaporated. Along with the metal portion, the plastic unsulation portionhad also melted, and bonded to the blade terminal of the starter relay.
WHY DID THE PUSH-ON QUARTER INCH TERMINAL FAIL???? Those connectors grip with a very large squeeze force and displace a bit of metal as they slide on. AND I was not going to be able to adequately crimp on replacement.
So the ultimate fix was to spend time cleaning the terminal if the starter relay adequately to allow an adequate solder connection.
That required a whole lot of cleaning and scraping, and the use of good electrical grade flux core solder. A very solid large lap-area solder connection and the processor is working again.
So I was asked to try to repair it, before he had to spend a few hundred on a replacement. OK, I would give fixing it a try.
But with all of those safety mechanisms, locating the problem would be a challenge, because any one of the systems could be just a bit off and keep it silent. AND it was vital to not impair any safety system .
So with a fair amount of misgiving I opened the bottom cover, which was quite adequately secured. two minutes of examnation revealed an unexpected failure which had no probable cause. It was not one of the safety interlock switches.
The motor is a highstarting torque capacitor induction motor that in addition to the large capacitor also uses a starter relay to open the start-winding once the motor approaches the rated speed. The wires connecting that motor used quarter inch push-on FASTON style terminals. One of those push-on connectors had failed, and with a whole lot of arcing, had evaporated. Along with the metal portion, the plastic unsulation portionhad also melted, and bonded to the blade terminal of the starter relay.
WHY DID THE PUSH-ON QUARTER INCH TERMINAL FAIL???? Those connectors grip with a very large squeeze force and displace a bit of metal as they slide on. AND I was not going to be able to adequately crimp on replacement.
So the ultimate fix was to spend time cleaning the terminal if the starter relay adequately to allow an adequate solder connection.
That required a whole lot of cleaning and scraping, and the use of good electrical grade flux core solder. A very solid large lap-area solder connection and the processor is working again.
