Respected members,

I have two queries regarding the new motors which are factory coupled to the pipeline with in a package equipment..This is in a petrochemical plant construction site.

1)What  are the pre-start up testing requirement?Can you give the standard reference for this?We have done winding resistance and megger test on these motors.Is it mandatory to  check vibration for the factory aligned coupled motors at site?We dont have any vibration test record from the factory.

2)If vibration check is mandatory,when this to be performed?Is it okey to check it during the pre-commissioning with dummy load?

Thank you for your valuable advise...


Ratheesh Vidyadharan









Original Post

I would certainly test vibration for the installation. Dependent upon construction you will possibly need HVA readings at each bearing location in Vel/Accel. Manufacturers may be able to provide vibration limits for this otherwise its just a case of using to ISO standards or similar (regional equivalent?) to compare against.  

Bearing manufacturer's may be able to provide limits for levels of acceleration for their rolling element bearings (if fitted).  

You can of course compare each motor which is also usefull.


I would be inclined to test on a dummy load as you suggested but also again when put into service.




I'm really not familiar with any general commissioning standards for the motors in petro-chem other than the API 541 and 547 standards for the motors themselves.  I believe that IEEE Std 841 motors meet these requirements.

There are still best-practices associated with electrical and mechanical testing to ensure reliability.  At a minimum, continuity and insulation resistance (IEEE Std 43-2013) and vibration analysis.  You can go the next step and perform high/low voltage Motor Circuit Analysis and Electrical Signature Analysis that will tell you more.

You can do verification prior to installation.  I've tested motors prior to shipping outside of the USA to verify that they meet electrical and mechanical standards and efficiencies.  However, an on-site check after will ensure proper installation and that no damage occurred to the machines.

Howard W Penrose

I would rather emphasize on what is bounden between you and the other parties. The contract usually is the primary reference. What you may find acceptable and fair might not be for the others. For them, it might be too little or too much based what they agreed on with you.

Many times, contacts are not detailed enough and they usually refer the parties to other references. You may end up with API, NEMA or I SO but I cannot assume.

Good luck.

Regards-Ali M. Al-Shurafa

Add Reply