Thursday, November 22, 2012

Rotor of Traction Motors

Audit of following Work Instructions was done in TM Shop. Report is as follows:-

MIG welding, Shrink ring fitment and dispatch work of Rotor Assembly( W 21.405):-
Points noticed:-

  • Protection while welding to be done by Glass Mica sheets as mentioned in para 3.3 of this WI should be done. Can heats conducting metal sheets be used?

  • Record of pre-heating current and temperature to be taken while pre-heating should be kept.

  • Baking to 300 degrees for 4 hours  after MIG welding as prescribed in para 3.10 of this WI is done.
  • Proof turning and ultrasonic testing after baking as mentioned in para 3.11 of this WI  should be done.
  • Cleaning after proof turning as mentioned in para 3.12 of this WI should be done.
  • Brazing of rotor bars on both sides as mentioned in para 3.13 of this WI should be done.
  • Since so many steps are to be followed and rotor still works, WI modification should be carried out.
  • Spray Painting of rotor after covering the groove with  nomex paper as mentioned in para 3.20 of this WI should be  done.

How Traction Motors Are Manufactured?

 Audit of following 3 Work Instructions was done in TM Shop. Report is as follows:-

Preparation of NDE End Frame  ( W 21.406):-
Points noticed:-

  • Compressed air cleaning aof end frame as mentioned in para 3.2.1 of this WI should be followed.
  • Fixing the Dowel and greasing with greasing nipple should be done. This WI needs modification.
  • Anti-rust compound Vevopol application on bearing cap as mentioned in para 3.2.10 is should be done.
  • Protection with adhesive paper tape as mentioned in para 3.2.15 is to be done.

Preaparation of DE End Frame ( W 21.407):-
Points noticed:-

  • Points noticed in previous WI hold good for this WI also.

Completion of DE & NDE End Frame , Temp. Sensor & Speed Sensor Assembly ( W 21.408):-
Points noticed:-

  • Compressed air cleaning of temperature detector hole should be done.
  • Drill cleaning of holes as mentioned in para 3.2 of this WI should be done.

  • Depth gauge reading of holes should be taken.

  • This WI mentions pouring RTV 622A+622B mixture in boreholes, which is different from practice, Foam plate application hence WI needs modification.

During inspection, In one of the finished job, half ring welding crack was observed and was reported to Production supervisor, and got attended.

Friday, November 16, 2012

Traction motor manufacturing

Audit of following 2 Work Instructions was done in TM Shop. Report is as follows:-

Preparation of Motor assembly  ( W 21.409):-
Points noticed:-
  • Vevopal anti-rust coating on stator is not being done, instead anabond is being used. WI needs modification.
Dismounting of Dummy Pinion and Mounting of Pinion  ( W 21.409):-
Points noticed:-
  • Use of Ring Gauge as mentioned in para 3.13, 3.14 should be done.
  • Dye transfer test as mentioned in para 3.15 of this WI should be done in all cases.
Reports from shed:-
BRC shed has reported some electrical failures in loco # 22917 same are being looked into.

ASN shed reported gauge widening in loco # HH-69-92. ( Despached in 2009) Record of same has been faxed to SrDEE TRS ASN.

Quality of crimpoing same was studied and inspected  in detail today in the shop.
Following is recommended:-
  • Pull out test schedule should be revised to once in 3 months.
  • All crimping tools should be renewd after every year.
It was told that last year the main crimping machine was out of order. Some failures might have developed in locos manufactured during that time only.

Thursday, November 8, 2012

World Class Traction Motors Produced by CLW

Audit of following 2 Work Instructions was done in TM Shop. Report is as follows:-

Routine test of 3-phase Traction Motor ( W 21.411):-
POints noticed:-
No Load Test:-

  • This WI is outdated. Resistance measurement by DC current injecting as mentioned in para 3.1.2 of this WI is done by micro-ohn meter nowadays. Additional measurement of Induction and PF is being done in shop which is not mentioned in WI
  • Tests are to be done on testbed after clamping. Same should be ensured. 
  • Rotor crack test on LV as mentioned in para 3.1.3 is also not done nowadays. WI needs modification
  • Intial test on 100 V for 5 min as mentioned in para 3.1.9 is to be ensuered.
No load Characteristic, Blocked rotor (SC) , Dielectric and IR  Test:-
  • All being done religiously.

  • Temperature probe calibration is done but , there should be a jig for same.

  • Some of the instruments/gauges used while testing are due for calibration.Same done.

Test of Assembled Traction Motor ( W 21.412):-
Points noticed:-

Dial gauge used for radial/axial play measurement is due for calibration.Same done.

Three Phase motor for locomotives

Audit of following 2 Work Instructions was done today in TM Shop. Report is as follows:-

Manufacturer of Rotor Core (Copper Stamping Design) ( W 21.414):-
Points noticed:-

  • Gauge for measuring pressing force of 45 T should be calibrated regularly..
  • Measuring and recrding of stack length as asked in para 3.17 of this WI should be followed.

Manufacturer of Rotor Core (Copper Stamping Design) ( W 21.415) Rotor bar insertion:-
Points noticed:-

  • Binding with steel tape as mentioned in para 3.8 of this WI should be follwoed. In case it is found redundant , WI should be modified.

While auditing of above WIs, Production staff was counseled about Railway Boards letter dated 16.12.2011 in which recommendation for preventing failures were given.

Defects list sent by BRCY shed was examined in shop floor.
Following is the analysis/action taken:-

  • Ba panel flashover:- deficiency has been pointed out earlier by inspection wing and request for  maintaining minimum 60 mm gap (between phase-earth) in busbars of BA-2 panel as per WI19.005 was made (vide above referred note) same being done.
  • Moreover, BA panels don’t bear any Serial Number, making it impossible to identify the staff who has worked upon in the BA panel provided in a particular loco.
  • Cable Crimpings of AC-2 panel manufacturing section are not sent for pull out test. Same started.
  • Line contactors L1,L2,L3 supplied by M/S Stesalit did not fail but L4,L5,L6 manufactured by CLW have failed. Kindly recall the letter dated vide which ensuring SS make hex bolts and spring washer was requested by quality wing.
  • Shunting contactor failure:-Letter has been written to supplier of Shunting contactor.
  • Other defects:-were informed to DyCEE-EL.
Above shows that CLW takes solid action on each shed's feedback.