ABB MT series Installation, Operation & Maintenance Manual

Also see for M2A series: Installation and maintenance instruction Instructions Installation, operation & maintenance instructions Machine Instructions Manual

ABB MT series Installation, Operation & Maintenance Manual Manual pdf 19 page image

9. TroubleshootingThese instructions do not cover all details or variations in equipment nor provide for every possible condition to be met inconnection with installation, operation or maintenance. Should additional information required, please contact the nearestABB Sales Office.Motor troubleshooting chartYour motor service and any troubleshooting must be handled by qualified persons who have proper tools and equipment.TROUBLE CAUSE WHAT TO DOMotor fails to start Blown fuses Replace fuses with proper type and rating.Overload trips Check and reset overload in starter.Improper power supply Check to see that power supplied agrees with motor rating plate andload factor.Improper line connections Check connections against diagram supplied with motor.Open circuit in winding or control switch Indicated by humming sound when switch is closed. Check for loosewiring connections.Also ensure that all control contacts are closing.Mechanical failure Check to see if motor and drive turn freely. Check bearings andlubrication.Short circuited statorPoor stator coil connectionIndicated by blown fuses. Motor must be rewound. Remove endshields, locate fault.Rotor defective Look for broken bars or end rings.Motor may be overloaded Reduce load.Motor stalls One phase may be open Check lines for open phase.Wrong application Change type or size. Consult equipment supplier.Overload Reduce load.Low voltage Ensure the rating plate voltage is maintained. Check connection.Open circuit Fuses blown, check overload relay, stator and push buttons.Motor runs andthen dies downPower failure Check for loose connections to line, to fuses and to control.Motor doesnot come up tonominal speedNot applied properly Consult equipment supplier for proper type.Voltage too low at motor terminalsbecause of line dropUse higher voltage or transformer terminals or reduce load. Checkconnections. Check conductors for proper size.Starting load too high Check the start load of the motor.Broken rotor bars or loose rotor Look for cracks near the rings. A new rotor may be required, as repairsare usually temporary.Open primary circuit Locate fault with testing device and repair.Low voltage motor manual 01-2009 | ABB Motors and Generators EN-19