Recent content by paramathma

Dear Friends, our supplier performed an observation on a failed electric motor of 3.5/5 KW. they gave us the megger value of new and failed motor. new failed 1 38 terminal u1-motor body 1 38 terminal v1-motor body 1 39 terminal w1-motor body 1 39 terminal u2-motor body 1 39 terminal v2-motor...

Thank you all for your inputs. Based on the motor manufacturing year, we decided to scrap some motors and not take risks.

water content was measured using karl fischer titration method

I found a paper in which they have mentioned that 1% of water will lead to corrosion. http://www.stle.org/assets/document/Environmental_Effects_on_Pitting_Corrosion_of_AISI_440C_Ball_Bearing_Steels-Experimental_Results.pdf

Opened the bearings and checked the moisture content in the grease. Weight % of water in the sample was approximately 1. Is this OK? what is the allowable range?

Friends, Will the long storage impact the grease in the ball bearings. Two Ball bearings used are sealed type. Will the long storage degrade the grease and impact the function of motor? What type of test is done to check the quality of grease in the bearing? thanks, Ana

See attached picture of rotorhttp://files.engineering.com/getfile.aspx?folder=6f878171-e591-486d-83a2-962f5cb40621&file=motor.jpg

Dear Friends, 3 years ago we purchased 200 numbers of 3 phase induction motors. Due to some reason, we did not use the motors and was in our ware house. Now we want to use the motors. Before assembling it on the machine, we opened one motor and found corrosion in rotor. I request motor...

Thank you all for the information. In this particular case along with rotor touching the stator, one wire in stator is open. Please see attached picture. Is it possible for the current to flow through this open wire to bearings via rotor shaft...

Thank you all for your valuable inputs jraef Question: Is this being run from a VFD or not? I do not know. The connection is from a control unit behind generator. We do not have access and information to this. EDM failure mode is seen in one motor. The EDM damage is predominantly seen in DE...

Friends, Only in one case we have seen EDM damage in bearing. Please see attached image. The image is from SKF catalog, mentions current passage when the bearing is not running. A similar observation is seen in Drive end inner ring, outer ring and balls of ball bearing. How will the current...

Hello experts, We are receiving failed electric motors from field. The motor is connected to a gear pump. Winding open is observed after checking the connectivity. Important observations after disassembly of motor Contact marks on drive end side of rotor and stator see attached figure Outer...

Hello all, Could you please explain over rolling direction? In many bearing articles Example: in Tribological Aspects of Rolling Bearing Failures by Jürgen Gegner, over rolling direction is mentioned on the picture. What is the difference between rolling and over rolling direction? How do we...

Hello All, What is the meaning of Full width half maximum (FWHM) in bearing Analysis? What does it specify? Ex: micro structure I have searched internet, but was not able to find article specifying importance of it. Thanks in Advance

Hi What is slip fit? I searched machinery hand book, but could not find information on slip fit. Where can find the tolerances for slip fit? What is the standard way of designating slip fit? For example we use H7/p6 for press fit similarly what we specify for slip fit? Thanks