Commutator Faults; Table 8-7 Commutator Faults - Siemens SIMOTICS DC 1HS7 Operating Instructions Manual

Operation
8.9 Faults
8.9.7

Commutator faults

Table 8-7 Commutator faults
Symptoms of fault
↓
↓
↓
↓
X
X
X
X
X
X
X
X
X
82
Beads of molten metal
Generally severe bar blackening
Some segments are blackened periodically
Some segments are severely scorched
↓ Flat spots on commutator
↓ Grooves in circumferential direction
Possible causes of faults
Plant fault
Poor alignment
X Mechanical jolts
Operating mode or operating error
X Continuous light-load duty (partial load)
X Temporary overload
X Overload at standstill
Cooling fault
Cooling air too damp
X Cooling air chemically aggressive
X Cooling air contains too much dust
X Cooling-air flow rate too high (commutator tem‐
perature too low)
Brush fault
Incorrect or unsuitable brush material
Brushes not in neutral zone
Component defect
Interruption in armature winding
Faulty solder joint
X Out-of-round commutator
Conductive inclusions in segment slots
Remedial measures
Align motor set
Improve installation
Change number of brushes and/or
material
Correct current limit
Correct current limit/shorten stand‐
still time
Change air ducting
Change air ducting
Change air ducting, use an air filter
Restrict air ducting (if necessary,
change brush material)
Change brush material
Correct setting
Repair winding
Resolder solder joint
Rework commutator
Pocket mill segment insulation
SIMOTICS DC 1HS7
Operating Instructions 02/2016