Pumps & Systems • January 2011

Aligning an electric motor coupled to a large air blower required multiple measurements.
Around 18 years ago, a client needed assistance aligning an electric motor (more than 1, 000 horsepower) coupled to a large air blower. This was a critical piece of equipment that was routinely shut down for preventive maintenance at regular intervals to ensure trouble-free operation. The mechanical contractor used for this alignment was reputable, and the customer had used him several times in the past for this task with satisfactory results.

Vibration Problems
Upon startup, vibration levels were so high that the package tripped and shut down before reaching full rpm, preventing any meaningful collection of vibration data to help identify the problem. This continued for two days. Convinced that the problem was alignment-related, the contractor made multiple corrections with the same results. Every time the package was started, vibration levels were high, and the package shut down before reaching full rpm.

Laser Shaft Alignment Assessment
The client requested that a shaft laser alignment system be used to ensure correct alignment. The motor and the blower were uncoupled, and all the hold-down bolts were at spec. Initial readings were taken. Remember, this was more than 18 years ago, so the alignment system was a much less sophisticated system than those available today.

Read the entire article Measure Twice, Cut Once!

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, by Dennis Onken