Danfoss MCD3000 Series Manual

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MCD3000 SeriesMG.15.A2.22 – VLT is a registered Danfoss trademar 39Design GuideApplication Benefits• Easier saw band alignment. Slowacceleration allows saw bands tobe 'tracked' without jogging.• Maximum overload capabilityavailable for ride through ofoperating overloads. TheMCD3000 motor thermal modelcan account for the connectedmotors actual overload capabilityand will trip only if absolutelynecessary.Chippers • Reduced starting current.• Instantaneous overload tripprevents mechanical damagefrom jammed loads.• Reduced deceleration timesthrough use of braking function.Crushers • Maximum overload capabilityavailable for ride through ofoperating overloads. TheMCD3000 motor thermal modelcan account for the connectedmotors actual overload capabilityand will trip only if absolutelynecessary.• Maximum start capabilityavailable for starting if crusherstopped while not completelyempty. The MCD3000 motorthermal model can account forthe connected motors actualoverload capability and will allowthe motor to provide start torquefor the maximum possible time. Power factor correctionIf a soft starter is used with static power factorcorrection it must be connected to the supply side ofthe starter.Connecting power factor correctioncapacitors to the output of the soft starterwill result in damage to the soft starter. Line contactorsMCD3000 soft starters can operate with or without aline contactor. If installing the MCD3000 without a linecontactor, ensure such connection complies with localregulations.Use of a line contactor or similar physical disconnectprovides better off state isolation than the soft starterthyristors. This improves operator safety.Use of a line contactor also eliminates the potential forextreme supply voltage disturbances to damage thesoft starter thyristors while they are in the off state.Voltage disturbances resulting from supply resonancecan typically be expected on high impedance supplieswith power factor correction. Use of a line contactor isprudent in such conditions.If using a line contactor and either the soft stop orD.C.Brake functions the line contactor cannot beopened until the end of the stop. The MCD3000should be used to directly control operation of the linecontactor. Set programmable relay output A or B tothe Line Contactor function.As an alternative to a line contactor, either a circuitbreaker with a no volt release coil operated by theMCD3000 N.C. trip output or a motor operated circuitbreaker can be considered. Soft brakingIn addition to the D.C.Brake function MCD3000 softstarters can be configured for 'Soft Braking'. Softbraking provides greater braking torque and lowermotor heating. Soft braking should be considered forhigh inertia loads such as chippers, crushers,bandsaws etc.To implement soft braking the MCD3000 is employedalong with reversing contactors and a rotation sensor.When a stop is called for, the phase rotation of thesupply to the starter is reversed and the motor is 'softstarted' in reverse thus providing braking torque. Therotation sensor is used to end braking when the motorhas stopped rotating.The MCD3000 secondary parameter set (Par. 25-33)can be used to control braking torque independentlyof starting parameters. This is done by setting startperformance using the primary parameter set (Par. 1-9) and braking performance using the secondaryparameter set (Par. 25-33). Closing the Par. Setcontrol input when the stop is initiated then activatesthe secondary parameter set.