ACQUIP Rentals ACQUIP Training shaft alignment February 16, 2024

How to use an ERAG/CAT step by step

What is an ERAG (Electronic Radial Alignment Gauge) / CAT (Concentricity Alignment Tool)?

This tool is designed to be used to concentrically align diaphragms to the shaft of a turbine.

With the Electronic Radial Alignment Gauge (ERAG) or Concentricity Alignment Tool (CAT), you don’t need to use a tight wire or a laser to line the parts. While the rotor is still in place, this tool can directly measure how much the diaphragm is out of line. One way to align this tool has been used for thousands of hours and has been shown to work.

Application of the ERAG/CAT

The Concentricity Alignment Tool (CAT) has two measuring heads, a large (LCAT) and small (SCAT). The LCAT head is to be used on larger turbines such as those manufactured by General Electric in Schenectady, New York.

The SCAT head is used on smaller turbines, such as those manufactured by General Electric in Lynn, Massachusetts. The SCAT head may also work on some smaller marine turbines.

What are the Benefits?

Simple Alignment Check with the Rotor in Place
Measures Diaphragm Misalignment To Center
Accurate to 0.001”

ERAG Parts for SCAT and LCAT

Procedure

Step #0

Setup SCAT/LCAT to Slide Through the Packing Hook-fit

Step #1

Insert tape measure into empty packing groove until it exits from the packing groove on the opposite side of the shaft.

Step #2

Attach the head to the end of the tape using the tape clip with the wire retainer to secure the end of the tape to the head.

Step #3

Insert the head into the packing slot by depressing the lever arm.

Step #4

Pull the head to the 3:00 o’clock position using the tape measure and then “zero” the meter using the coarse adjustment on the head and the fine adjustment on the power supply.

Step #5

Pull the head to the 3:00 o’clock position using the tape measure and then “zero” the meter using the coarse adjustment on the head and the fine adjustment on the power supply.

Step #6

Pull the head to the 3:00 o’clock position using the tape measure and then “zero” the meter using the coarse adjustment on the head and the fine adjustment on the power supply.