Motor Malfunctions - SEW-Eurodrive DR2..71/BE Series Operating Instructions Manual

9.1

Motor malfunctions

Fault
Motor does not start up Supply cable interrupted
Motor only starts with
difficulty or does not
start at all
Motor does not start in
star connection, only in
delta connection
Incorrect direction of
rotation
Motor hums and has
high current consump-
tion
Fuses blow or motor
protection trips immedi-
ately
Possible cause
Brake does not release
Supply cable fuse has blown
Motor protection (switch) has
triggered
Motor protection does not trip
Malfunction in control or in the
control process
Motor power designed for delta
connection but connected in star
Motor power designed for double-
star connection but only connected
in star
Voltage or frequency differs con-
siderably from the setpoint, at
least when switching on the motor
Star connection does not provide
sufficient torque
Contact fault on star/delta switch
Motor connected incorrectly
Brake does not release
Winding defective
Rotor rubbing
Short circuit in the motor supply
cable
Supply cables connected incor-
rectly
Short circuit in the motor
Ground fault on motor
Measure
Check the connections and (intermediate) ter-
minal points, correct if necessary
See chapter "Brake malfunctions"
Replace fuse
Check that the motor protection (switch) is set
correctly; current specification is on the name-
plate
Check motor protection control
Observe the switching sequence; correct if
necessary
Correct the connection from star to delta;
Observe wiring diagram
Correct the connection from star to double-
star;
Observe wiring diagram
Provide better power supply system; reduce
the power supply load;
Check cross section of supply cable, replace
with cable of larger cross section if necessary
If the delta inrush current is not too high (ob-
serve the regulations of the power supplier),
start up directly in delta;
Check the project planning and use a larger
motor or special design if necessary. Contact
SEW‑EURODRIVE
Check the switch, replace if necessary;
Check the connections
Swap 2 phases of the motor supply cable
See chapter "Brake malfunctions"
Send motor to specialist workshop for repair
Send motor to specialist workshop for repair
Eliminate short circuit
Correct the connection;
Observe wiring diagram
Send motor to specialist workshop for repair
Send motor to specialist workshop for repair
Operating Instructions – AC Motors
Malfunctions
9
Motor malfunctions
227