On a motor-to-reducer connection, the coupling often sits inside a compact guard or adapter arrangement. That makes D, L and the required hub separation just as important as nominal torque.
Use input-side torque and speed.
Size the coupling around the conditions at the shafts it physically connects. Do not use gearbox output torque with input speed in the same selection step. If you only have motor power and input rpm, provide both so the requirement can be checked consistently.
Describe the reducer input shaft exactly.
State the reducer input shaft diameter and keyway separately from the motor shaft. If an adapter plate or bell housing limits the coupling outside diameter, add that available space to the RFQ. Where shafts are stepped or unusually short, a small sketch is often faster than a paragraph.
Comparing several motor/reducer combinations?
Combine the model list, shaft sizes and quantities in one enquiry. Mixed models can be reviewed together under the stated commercial MOQ policy.
