Troubleshooting :: Soft Serve :: Troubleshooting a 1-Phase Motor

Introduction

Required Tools

1. Metric Hex Driver or Allen key set
2. Flathead Screwdriver set
3. Clamp-style Amp Meter
   

Troubleshooting Capacitor Health

Warning: Capacitors are very dangerous.  Always be careful when handling, and treat all capacitors as charged until verified otherwise.  Use appropriate tools to discharge a capacitor and verify capacitor charge.

Symptoms of Capacitor deterioration:

1. Shorted capacitors may blow fuses or damage other components in the machine.  
   
2. Open or deteriorated capacitors will result in open circuits within the machine or components not operating.
   
3. Capacitors have a limited life and will have to be replaced eventually when deteriorated.

1. Unplug the machine from the wall and turn the power switch OFF
2. Remove the side and rear panels from the machine as necessary to allow access to the start and run capacitors.  Each motor will have one of each, usually in a light grey enclosure with yellow and blue wires running to them.
3. Remove the cover of the main electrical box.  Depress the motor contactor(s) to discharge the motor capacitors.
4. Inspect the physical condition of the capacitor.  Check for leakage, cracks, bulges, or other signs of deterioration.  Replace the capacitor if any of these is present.
5. Remove the wires from the capacitor terminals.  Use a multimeter to verify the capacitor is fully discharged.
6. Use the Capacitance Measurement Mode of the multimeter and connect the test leads to the capacitor terminals.  Allow a few seconds for the multimeter to read the capacitance.
7. The capacitance should read +/- 20% from the capacitor specifications on the capacitor body.  Any reading outside this range indicates a failing capacitor that should be replaced.  If you read “OL”, this means the value is out of range.  Try again, and if you have the same result, replace the capacitor.

Troubleshooting Motor Windings

1. Unplug the machine from the wall and turn the power switch OFF
2. Remove the side and rear panels from the machine as necessary to allow access to the start and run capacitors.  Each motor will have one of each, usually in a light grey enclosure with yellow and blue wires running to them.
3. Remove the cover of the main electrical box.  Depress the motor contactor(s) to discharge the motor capacitors.
4. Visually inspect the motor for signs of burning, jammed drive shaft, or other physical damage.  Spilled product or water, corrosion, or other signs of liquid are also indications of a failure.  Replace the motor if any of these items have occurred.
5. Use the Ohmmeter mode of the multimeter to measure the resistance of the starting and running windings across the two motor wire leads (black wires).
6. A zero reading indicates a short in the windings.  An infinity reading indicates an open circuit in the winding.  The motor should be replaced in either case.  A nominal ohm reading indicates the windings are good, and the motor should not be replaced.