
MEP 660 - Trouble shooting Manual
Doc No.: IM – 51
Rev.2.0
Print: October 2008
20
cable.
J. If the Voltage is equal to the Exciter Voltage, then check the
Voltage on the Traction Alternator brush arms.
Extreme care should be taken while measuring the Voltage at
the Traction Alternator slip rings. It is highly recommended to
shut down the engine and connect measuring leads at the brush
arms. After connecting the leads to meter, set up the
locomotive as per the Sl. No. 1 to 3.
K. If the Voltage is zero, then
a) The cables AF1 and AF2 connecting Traction Alternator brush
arms and back side TB are having high resistance / open
circuit. Check and replace the cables.
L. If the Voltage is equal to Exciter Voltage, then
a) The problem is inside the Traction Alternator. Check the
following and fix up the problem
1) Check up the brush arms and brushes for any open
circuit / burnt sysmptoms.
2) Check up for any discoloration of slip rings that can
cause bad contact between brushes and slip rings.
3) Check up any burnt / fused slip ring connections.
4) Check for any open circuit in the Traction Alternator Field
circuit.
5. If every thing is nrmal, measure the Traction Alternator Field
current with a clip on DC ammeter clipped to any one of the
Traction Alternator Field cables.
6. If the meter indicates current and the value of EXAI on the display
is less / zero, then
A. The communication cable between the current sensor EXAI and
MEP-660 is bad. Check the continuity of the cable and if
necessary replace the cable.
B. If the cable is good, then the sensor is bad. Replace the sensor.
7. Return the throttle to IDLE.