1. Check the WP sample table according to torque and speed to determine the model.
WP model format: WPA/WPO/WPDA/WPDO + frame number (center distance) + speed ratio
Frame number (center distance): 40, 50, 60, 70, 80, 100, 120, 135, 155, 175, 200, 250
Example: WPA100-30 → horizontal, center distance 100mm, speed ratio 30
Lookup table logic:
Find the corresponding speed segment according to the output speed n₂;
According to the calculated T₂, select the smallest frame number with rated output torque ≥ T₂;
Under the same torque, the higher the speed, the frame size should be appropriately enlarged.
2. Key verification (avoiding heating/overloading)
Thermal power check (required for continuous operation)
Motor input power ≤ reducer thermal power (sample table), otherwise it will overheat and become stuck during long-term operation.
Enter speed limit
WP worm speed ≤ 1500 r/min, exceeding will aggravate wear.
Installation form confirmation
WPA: Horizontal, worm underneath
WPO: Horizontal, worm on top
WPDA: vertical, worm under the
WPDO: vertical, worm mounted on top
3. Complete Selection example
Known: Motor P=2.2kW, n₁=1450r/min, n₂≈48r/min required, medium impact.
Reduction ratio: i=1450/48≈30 → choose standard i=30
Motor torque: T₁=9550×2.2/1450≈14.5 N・m
Theoretical output torque: T₂₀=14.5×30×0.75≈326 N・m
SelectionTorque (f=1.3): T₂=326×1.3≈424 N・m
Look up the table: n₂=48r/min, T₂≥424N・m → choose WPA135-30 (rated torque ≈ 450N・m, satisfied)
