1. What is Hydraulic Motor Displacement?

Definition: This calculator determines the required displacement of a hydraulic motor based on the available flow rate and desired rotational speed.

Purpose: It helps hydraulic system designers and maintenance technicians select the appropriate motor size for their application.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( D_m \) — Motor displacement (cubic inches per revolution)
• \( Q \) — Flow rate (gallons per minute, GPM)
• \( RPM \) — Desired motor speed (revolutions per minute)
• 231 — Conversion factor (cubic inches per gallon)

Explanation: The formula calculates the volume of fluid required per revolution to achieve the specified RPM at the given flow rate.

3. Importance of Proper Motor Selection

Details: Correct motor sizing ensures optimal system performance, prevents overloading, and maximizes energy efficiency in hydraulic systems.

4. Using the Calculator

Tips: Enter the available flow rate in GPM and the desired motor speed in RPM. Both values must be greater than 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the 231 constant in the formula?
A: 231 is the number of cubic inches in one US gallon, used to convert GPM to cubic inches per minute.

Q2: What if my motor speed is too low for the calculated displacement?
A: You may need a larger displacement motor or consider using a flow control valve to reduce flow to the motor.

Q3: How does motor efficiency affect this calculation?
A: The formula assumes 100% volumetric efficiency. For real-world applications, divide the result by the motor's efficiency (typically 0.85-0.95).

Q4: Can I use this for hydraulic pumps as well?
A: Yes, the same formula applies to pump displacement calculations when you know the desired flow and drive speed.

Q5: What about metric units?
A: For metric (cm³/rev), use: \( D_m = \frac{Q \times 1000}{RPM} \) where Q is in liters/minute.