Power ground cases of EMD locos
and Action plan.
There have been large number
of loco failures (eighteen) due to “Power ground Faults”. Three failures
(20048, 20014 & 12280) due to power ground failure were in last two months
alone.
Shed should measure IR value
of Power circuit and Control circuit. Power circuit should further be
sub-divided in branches and IR value of each branch should be taken. Any fall
in value from previous reading or from other loco readings should be wakeup
call and reason of drop in IR value should be carefully checked as per check
list in each branch in all possible locations systematically. Shed should issue
desirable IR value achieved in best 10% of loco) in power circuit and strive to
maintain the same during every schedule.
The detail of failures and action plan as per
maintenance schedule is given in annexure. Most of these cases are due to
insulation puncture of Traction motor power cables. Special drive should be
launched for attending TM cables.
Suggested action plan to
avoid such failures in near future is given below.
|
SN
|
ITEM
|
Details
|
Action to take
|
|
1
|
TM phase cable
|
1.
Cable insulation damage inside and at facing point of rubber cleat
(20011 on
8/7/07)
(20004
on7/11/07)
(20012
on3/5/08)
(20000 on
28/7/08)
(20015 on
7/11/08)
(2000 on
21/11/08)
(20017 on
18/2/08)
(20051 on
17/4/09)
(20014 on
1/2/08)
(12064 on
30/6/09)
(20079 on
11/8/09)
(12064 on
119/09)
(12166 on
23/10/09)
(12179
on 19/7/09)
|
1.a.
Introduction of soft rubber gasket over
cable inside rubber cleat.
1.b. Proper securing of cables to arrest cable swing during run. |
|
2.Cable
torn due to excessive lurching
(20048
on 23-6-2008)
|
2.a.
Re-arrange cable route and keep
sufficient cable length so that
stretching of cable does not take
place at maximum lurching .
Please ensure that the over length cable
does not swing or rub.
2.b.
Attention for Bogie and Yaw dampers
to avoid lurching
|
||
|
3. Cable
insulation rubbed with bolts of TM coupling bracket board.
(20014on
1/2/08)
|
3.a. One special drive to inspect all such vulnerable location.
3.b. Application of suitable cable protection
like heat shrinkable sleeve and gasket in such locations.
|
||
|
4.
Un insulated portion of cable joint which is housed inside an umbrella boot over
TM coupling bracket board burnt out.
(12064
on 27/7/09)
|
4.a.
Inspection of umbrella boot for porosity
and other physical damage.
4.b. Replace the boot instead of repairing. 4.c. Cover up all un - insulated terminal joints inside umbrella boot with self fusible insulating tape. 4.d. Use sealant at the cable entrance into the umbrella boot to arrest water ingress inside umbrella boot. |
||
|
2
|
TCC
out put phase cable
|
1.
TCC-2 phase V cable (out put) surface is cable insulator was worn out at the
entrance of cable duct inside Central air compartment.
(20085
on 7/5/09)
|
1.a.
Checking of all power cable lay out
and fixtures during commissioning of
new locomotive. It should be
made 360 days schedule checking item.
1.b. One special drive for inspection of power cables in all critical locations of all locos. |
|
3
|
TCC
cable TM45RT cable
|
1.
TCC2 cable TM45RT cable insulation cracked behind ECC1 cabinet and power
ground occurred when came into contact with rain water.
(20014
on 28/6/10)
|
1.a. Checking
of all cable insulation behind
ECC1 cabinet by removing foot board
of all locos.
1.b. Air blowing and proper cleaning of cables of that location. 1.c. Apply sealant in leaky location . 1d. Door locking arrangement of all doors should be properly functional and water should not drip inside. |
|
4
|
Insulator
at the back of L456 reactor
|
L456 reactor insulator in ECC2 back side of
the reactor core damaged due to less gap with wall causing power ground.
(20048
on 6/5/2010)
|
1.a. One special
drive for checking of gap
between the reactor and the ECC2 wall in all locos.
1.b Use insulated sheet or nomex paper in between reactor and ECC2 cabinet wall. |
|
5
|
ECC2
terminal board
|
1.Rain
water entered inside ECC2 and high voltage terminal board grounded.
(12280
on 30/6/2010)
|
1.a.
Fabricate and introduce ECC2 cable duct cover for WDG4 locomotives to restrict water ingress through harness.
1.b.
Use RTV sealant at cable entrance for
ECC2.
1.c.
Check door gaskets for deformation and .If deformed replace it.
1.d.
Ensure the ECC2 bottom drain hole
clean.
E)
Transfer HV terminal points towards top of the terminal board.
F)
Spray insulated paint over non insulated area of terminal board including
terminal lugs and posts
|
These instructions should be
explained to concerned staffs and supervisors .Shed should create an exhaustive
check list and action plan to attend power ground case.
You are advised to introduce
the above maintenance practice immediately and send feed back to HQ regularly.
