## Which formula is correct for power screw?

Power screws can be self-locking when the coefficient of friction is high or the lead is small, so that π µt dm > L or, equivalently, µf > tan λ.

## What is the efficiency of a self locking Power screw * 70%?

Explanation: Efficiency of self locking screws is less than 1/2 or 50%.

How do you find the ma of a screw?

Calculate the mechanical advantage of the screw by dividing the circumference of the screw by the pitch of the screw. Using the previous examples, a screw with a pitch of 1/8 and a circumference of 0.79 inches would produce a mechanical advantage of 6.3.

What is self locking of screw?

Self-locking in power screws refers to the condition in which a screw cannot be turned by the application of axial force on the nut. This is very useful in that a power screw that is self-locking will hold its position and load unless a torque is applied.

### Which of the following is true for self-locking screw?

∴ A screw will be self-locking if the coefficient of friction is equal to or greater than the lead angle.

### What is the efficiency of a self locking Power screw * 70% 60% 55% 50 Option 2?

For self-locking, the maximum efficiency of the screw should be 50%.

What is the condition for self locking?

Self-locking: When ϕ is greater than or equal to α, a positive torque is required to lower the load. Under this condition, the load will not turn the screw and will not descend on its own unless an effort P is applied.