Simpull Pull Calculator

Simpull Pull Equation:

\[ T_{out} = T_{in} \times e^{\mu \times \theta} \]

Output Tension (T_out):

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1. What is the Simpull Pull Equation?

The Simpull Pull Equation calculates the output tension (T_out) required when pulling cable or wire through conduit based on input tension (T_in), coefficient of friction (μ), and the angle of bend (θ) in radians. This equation is essential for determining the maximum allowable pulling tension to prevent damage to cables during installation.

2. How Does the Calculator Work?

The calculator uses the Simpull equation:

\[ T_{out} = T_{in} \times e^{\mu \times \theta} \]

Where:

\( T_{in} \) — Input tension (lb or N)
\( \mu \) — Coefficient of friction (dimensionless)
\( \theta \) — Angle of bend (radians)
\( e \) — Euler's number (approximately 2.71828)

Explanation: The equation demonstrates how tension increases exponentially as cable is pulled around bends, with the rate of increase determined by the coefficient of friction and the angle of the bend.

3. Importance of Pull Tension Calculation

Details: Accurate pull tension calculation is crucial for preventing cable damage during installation, ensuring proper cable performance, and maintaining safety standards. Excessive tension can cause insulation damage, conductor stretching, or complete cable failure.

4. Using the Calculator

Tips: Enter input tension in pounds or newtons, coefficient of friction (typically 0.15-0.5 for most cable/conduit combinations), and bend angle in radians. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What are typical values for coefficient of friction?
A: For most cable/conduit combinations, μ ranges from 0.15 to 0.5. Lubricated pulls typically have lower coefficients (0.15-0.25), while dry pulls have higher values (0.3-0.5).

Q2: How do I convert degrees to radians?
A: Multiply degrees by π/180. For example, 90° = 90 × π/180 = π/2 ≈ 1.57 radians.

Q3: What is the maximum safe pulling tension?
A: Maximum tension varies by cable type and size. Generally, it should not exceed 0.008 × n × CMA (circular mil area) for copper or 0.006 × n × CMA for aluminum, where n is the number of conductors.

Q4: Does this equation account for multiple bends?
A: For multiple bends, calculate sequentially: the output tension from one bend becomes the input tension for the next bend.

Q5: When should I use cable lubricant?
A: Use cable lubricant when calculated tensions approach or exceed cable limits, when pulling through long conduits, or when navigating multiple or sharp bends.