Motor control of a drain cleaning machine

A method for controlling a drain cleaning machine to move a snake in a drain, the method comprising:

• determining, with an electronic processor of the drain cleaning machine, motor positional information of a brushless DC motor of the drain cleaning machine, the brushless DC motor being configured to rotate a snake about a snake axis defined by a snake passage;
• controlling, with the electronic processor, power switching elements to drive the brushless DC motor based at least partially on the motor positional information, the power switching elements being configured to control an amount of current provided to the brushless DC motor;
• in a first operating range when a load experienced by the brushless DC motor is less than or equal to a predetermined load, controlling, with the electronic processor, the power switching elements to drive the brushless DC motor at an approximately constant speed regardless of the load experienced by the brushless DC motor;
• and
• in a second operating range when the load experienced by the brushless DC motor is greater than the predetermined load, controlling, with the electronic processor, the power switching elements to drive the brushless DC motor at a decreasing speed as the load experienced by the brushless DC motor increases.

A drain cleaning machine for moving a snake in a drain, the drain cleaning machine comprising:

• a snake passage defining a snake axis;
• a brushless direct current (DC) motor configured to rotate a snake about the snake axis;
• power switching elements configured to control an amount of current provided to the brushless DC motor;
• and
• an electronic processor coupled to the power switching elements, and configured to
• determine motor positional information of the brushless DC motor and control the power switching elements to drive the brushless DC motor based at least partially on the motor positional information,
• wherein the electronic processor is configured to control the power switching elements to drive the brushless DC motor to operate at one or more user selectable parameters.