Calculation formula for WP series cast iron turbine worm gear reducer matching motor

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Step 1: WP series turbine worm reducer and motor power matching

The matched motor power shall not exceed the value specified on the reducer nameplate

Use standard three-phase asynchronous motors (e.g. avoid non-standard ratings such as 4.4 kW)

Verify whether the diameter of the motor output shaft and keyway match the input size of the reducer

Complete Selection Example

Given:

• Motor power: P = 2.2 kW

• Motor speed: n₁ = 1450 r/min

• Required output speed: n₂ ≈ 48 r/min

• Duty: Moderate impact

Step 1 – Reduction ratio:

i = 1450 / 48 ≈ 30 → Select standard i = 30

Step 2 – Motor torque:

T₁ = 9550 × 2.2 / 1450 ≈ 14.5 N·m

Step 3 – Theoretical output torque (η = 75%):

T₂₀ = 14.5 × 30 × 0.75 ≈ 326 N·m

Step 4 – Selection torque (f = 1.3):

T₂ = 326 × 1.3 ≈ 424 N·m

Step 5 – Table lookup:

At n₂ = 48 r/min, T₂ ≥ 424 N·m → Select WPA135-30 (rated torque ≈ 450 N·m)

Need Help with Selection?

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