Shear Pin

Each WesTech drive is equipped to handle scenarios where torque limits are exceeded. In the unlikely event that the limit switches have failed, a WesTech drive may be equipped with a shear pin fail safe. This ensures that your WesTech drive has an additional layer of protection from torque overload due to a variety of conditions.

When the shear pin is sheared the direct coupling will continue to rotate but the shear pin plate will remain stationary. At this time, the shear pin must be replaced.

Be sure to disconnect the power before beginning this procedure. Proper lockout/ tag out procedure should be followed for the safety of the individuals working on the drive. If you have questions regarding this please consult your plants safety officers and/or guides.

To begin the motor, the reducer and the adapter plate must be removed. This can usually be done by detaching the unit as a whole however, if the assembly is too heavy, it is advised to remove the motor first, and then remove the reducer. This will enable you to ensure safety while changing the shear pin.

The shear pin is located behind a guard on the direct coupling housing. Remove this guard.

Next remove the bolts that attach the adapter to the drive unit. A quick shake of the motor to break it loose, enables you to remove the motor assembly from the drive unit.

By prying the coupler off the shaft using a small pry bar or screw driver, remove the coupler from the shear pin plate and off the shaft. It should slide off with minimal force.

Now that the coupler is removed, push the shear pin through the coupler.

The other half can be pushed through drive unit and should fall out to be retrieved.

New shear pins can be found in the torque box. Once the new shear pin is located, the coupler can be reattached to the shear plate by inserting the new shear pin into the shear pin seat.

Before reassembly, generously coat each mating surface in anti-seize. This includes the shear pin plate, shaft, coupling, and the reducer input shaft. With the mating surfaces coated in anti-seize, reassemble the adapter plate, reducer, and motor assembly. Finally replace the shear pin guard.

Finish this process by completing the lockout/ tag out procedure and restart the drive unit.

You have now completed a shear pin replacement for a WesTech drive.

If your shear pin fails again, inspect the tank for obstructions to the rake arms. Binding of the rake arms can occur and cause torque overload when debris or other foreign material is present in the tank.

If you have further problems or questions contact your local WesTech representative.