Systems and methods for rotary knob friction adjustment control

A circuit breaker, comprising:

• a trip unit including an internal support, the internal support including a first opening to receive a first rotary knob having one or more first smooth rings, a second opening to receive a second rotary knob having one or more second smooth rings, a first pair of slots and a second pair of slots;
• a first knob control of the first rotary knob, the first knob control including a first spring installed in the first pair of slots to apply a force directly against the one or more first smooth rings of the first rotary knob;
• and
• a second knob control of the second rotary knob, the second knob control including a second spring installed in the second pair of slots to apply a force directly against the one or more second smooth rings of the second rotary knob.

A method of controlling rotational positions of knobs in a thermal magnetic trip unit of a circuit breaker, the method comprising:

• providing a first opening in an internal support of a trip unit to receive a first rotary knob having one or more first smooth rings;
• providing a second opening in the internal support to receive a second rotary knob having one or more second smooth rings;
• providing a first knob control of the first rotary knob, the first knob control including a first structural support, a first housing and a first spring installed in the first housing against the first structural support;
• providing a second knob control of the second rotary knob, the second knob control including a second structural support, a second housing and a second spring installed in the second housing against the second structural support;
• applying a first force onto the first housing such that the first housing pushes directly against the one or more first smooth rings of the first rotary knob to provide control over a plurality of rotational positions of the first rotary knob by at least one of friction, force, and pressure adjustment;
• and
• applying a second force onto the second housing such that the second housing pushes directly against the one or more second smooth rings of the second rotary knob to provide control over a plurality of rotational positions of the second rotary knob by at least one of friction, force, and pressure adjustment.