Not Characteristic of a Positive Contact Clutch:

Positive contact clutches are a type of clutch mechanism commonly used in various mechanical systems. They operate by having direct physical contact between the driving and driven members, providing a more efficient transfer of power. However, there is one characteristic that sets them apart from other types of clutches.

Frictional Engagement:
- Positive contact clutches rely on frictional engagement between the driving and driven members to transmit power.
- The contact surfaces are designed to grip each other tightly, ensuring a strong and efficient transfer of torque.
- This direct contact allows for precise control over the engagement and disengagement of the clutch, making it suitable for applications where accuracy is crucial.

Not Characteristic:
- Unlike other types of clutches that rely on fluid or magnetic forces for engagement, positive contact clutches do not require any intermediate medium to transmit power.
- This direct mechanical contact can result in higher wear and tear on the contact surfaces, leading to more frequent maintenance and replacement intervals.
- The need for precise alignment of the contact surfaces also means that positive contact clutches may be more sensitive to misalignment or improper installation.

In conclusion, the lack of reliance on an intermediate medium for power transmission and the potential for higher wear and sensitivity to misalignment are factors that set positive contact clutches apart from other clutch types.