Lobe, Helical Screw Blowers

Helical Screw Blowers and Lobe Blowers typically have 2 shafts. One shaft is driven by the motor, and the second shaft gets rotation from a gear set on the Driven End or Non-Driven End of the blower, or sometimes can be driven by the blades of the blower.

Try to identify where the gear set is that is translating rotation, and where the bearings are that support the shaft. Install on the metal piece that is holding the bearings, and try to avoid installing over the gear set, which might not show all of the vibration from the bearings.

Source: https://www.gardnerdenver.com/en-lac/blowers/helical-screw-technology/cycloblower-vhx/

Source: https://www.elmorietschle.com/en-us/products/rotary-lobe