Troubleshoot AC Motors – Part 2

This is a 4 part series, click to view each part: 1 : 2 : 3 : 4

B1: Are vibrations and noise from driven machine or power transmission system being transmitted to motor?		Locate source of noise and reduce. Isolate motor with belt drive or elastomeric coupling.

B2: Is a hollow motor foundation acting as a sounding board?		Redesign mounting. Coat foundation underside with sound dampening material.

B3: Check motor mounting. Is it loose?		Tighten. Be sure shaft is aligned.

B4: Is motor mounting even and shaft properly aligned?		Shim feet for even mounting and align shaft.

B5: Is fan hitting or rubbing on stationary part or is object caught in fan housing?		Repair damaged fan, end bell or part causing contact. Remove trash from fan housing.

B6: Is air gap nonuniform or rotor rubbing on stator?		Recenter rotor rubbing on worn bearings or relocate pedestal bearings.

B7: Listen to bearings. Are they noisy?		Lubricate bearings. If still noisy, replace.

B8: Is voltage between phases (three-phase motors) unbalanced?		Balance voltages.

B9: Is three-phase motor operating on one-phase? (Won’t start on single-phase.)		Restore power on three-phases.

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