Complete Packages

ERAG / CAT Concentricity Alignment Tool

ERAG rental from ACQUIP, makes moving the instrument between two adjacent surfaces a breeze.


Electronic Radial Alignment Gauge (ERAG) or Concentricity Alignment Tool (CAT) negates the need for tight wire and/or laser alignment. This tool can directly measure the amount of diaphragm misalignment with the rotor in place. This tool have a proven alignment method through thousands of hours of use.

ERAG/CAT Concentricity Alignment Tool features:

• Directly measures the amount of diaphragm misalignment with the rotor in place.
• Alignment method proven through thousands of hours of use.
• Easy to use – direct readout.
• Accommodates a wide range of turbine sizes.
• Very accurate (resolution to .0001 inch – accuracy plus or minus.0005 inch maximum).


µERAG (micro CAT) was born from the need to measure diaphragm misalignment on new turbine models with a very small radial clearances. The new head fits on a width slot 0.500″ (same as SCAT) and allows you to measure radial clearances from 0.200″ to 0.250″. Please contact us for additional information on the µERAG (micro CAT) at or call us at +1 305 538 7101.

How to Use the ERAG/CAT for my Project?

  1. Inserted into the empty packing groove, the Concentricity Alignment Tool (CAT) allows annular space variations to be displayed on a LCD display as it is pulled through the packing groove as shown.
  2. The head “rub bars” ride on the turbine shaft and the head lever arm rides on the ID of the diaphragm. As the head is pulled through the packing groove, the lever arm follows the contour of the diaphragm ID and the dimensional variation is displayed.
  3. ERAG have a main body to which there is pivotally coupled a U frame whose arms extend at an angle from its base, so that as the former is pivoted in one direction, the latter will correspondingly pivot in an opposite direction.
  4. Contact points are provided to the arms and the bottom surface of the body, and the base of the U frame is biased by a spring-loaded slidable element within the body, which in turn is connected to a transducer.
  5. An ideal way to accomplish alignment is with the rotor in place so the dimension from rotor to seal carrier can be measured directly. One of the best methods of measuring between the rotor and the carrier includes an ERAG.

For more information about the ERAG please contact us at or call us at +855 ACQUIP1 you can also learn more about our alignment services in the field visiting our projects gallery.

Check out erag video overview
Jeff Burleson
Steel Related Technology

Working with ACQUIP on the job we had in Italy recently was the best experience I have had in this type situation. ACQUIP was very professional and the response time far exceeded my expectations. The rental equipment was in top shape and made it possible for us to take care of our customer in an emergency situation. We will look forward to doing business with you in the future. Thank you for your hard work.

David M. Casto
Regional Quality Engineer

ACQUIP’s engineers performed a great job for Siemens Energy . The Fluid Drive and Gearbox and Pump were all included in the task. Each component was aligned to “all” of Siemens procedures and specifications requested. The Siemens customer was very satisfied with the results of the alignment and process.

Owen O’Donnell
Furino and Sons Inc.
Project Manager

First I would like to thank you for your help. We need a piece of alignment equipment on site last minute do to a break down. ACQUIP responded to your request immediately, recommend the right tool for the job, and had the tool on site by 8:30 AM the following morning. Just outstanding customer service and support from the entire ACQUIP team.

Danny Hiner
Tamarack Aerospace Group
Metrology Engineer

ACQUIP was the best choice to rent the Laser Tracker. It speeded up the process! I will definitely come back on our next set of fixtures!

Don Haag
Reliable Turbine Services
Vice President of North Operations

I highly recommend ACQUIP for executing both Tops on/Tops off and Tops off Steam path alignments.

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