Danfoss VLT HVAC Drive FC 102 Programming Manual

Also see for VLT HVAC Drive FC 102: Operating instructions Service guide Programming guide Installation guide Installation guide

Contents

1-73 Flying StartOption: Function:This function enables catching a motor which isspinning freely due to a mains drop-out.When parameter 1-73 Flying Start is enabled,parameter 1-71 Start Delay has no function.Search direction for flying start is linked to thesetting in parameter 4-10 Motor Speed Direction.[0] Clockwise: Flying start searches in clockwisedirection. If not successful, a DC brake is activated.[2] Both Directions: The flying start first makes asearch in the direction determined by the lastreference (direction). If the speed is not found, itmakes a search in the other direction. If notsuccessful, a DC brake is activated in the time setin parameter 2-02 DC Braking Time. Start thentakes place from 0 Hz.[0] Disabled Select [0] Disable if this function is not required.[1] Enabled Select [1] Enable to enable the frequencyconverter to catch and control a spinning motor.The parameter is always set to [1] Enable whenparameter 1-10 Motor Construction=[1] PM non-salient.Important related parameters:• Parameter 1-58 Flying Start Test PulsesCurrent• Parameter 1-59 Flying Start Test PulsesFrequency• Parameter 1-70 PM Start Mode• Parameter 2-06 Parking Current• Parameter 2-07 Parking Time• Parameter 2-03 DC Brake Cut In Speed[RPM]• Parameter 2-04 DC Brake Cut In Speed [Hz]• Parameter 2-06 Parking Current• Parameter 2-07 Parking Time[2] EnabledAlways[3] EnabledRef. Dir.[4] Enab.AlwaysRef. Dir.The flying-start function used for PM motors is based onan initial speed estimation. The speed is always estimatedas the first thing after an active start signal is given. Basedon the setting of parameter 1-70 PM Start Mode thefollowing happens:Parameter 1-70 PM Start Mode=[0] Rotor Detection:If the speed estimate appears as greater than 0 Hz, thefrequency converter catches the motor at that speed andresumes normal operation. Otherwise, the frequencyconverter estimates the rotor position and start normaloperation from there.Parameter 1-70 PM Start Mode=[1] Parking:A speed estimate lower than the setting inparameter 1-59 Flying Start Test Pulses Frequency engagesthe parking function (see parameter 2-06 Parking Currentand parameter 2-07 Parking Time). Otherwise, the frequencyconverter catches the motor at that speed and resumesnormal operation. Refer to the description ofparameter 1-70 PM Start Mode for recommended settings.Current limitations of the flying-start principle used for PMmotors:• The speed range is up to 100% nominal speed orthe field weakening speed (whichever is lowest).• PMSM with high back EMF (>300 VLL(rms)) andhigh winding inductance (>10 mH) needs moretime for reducing short-circuit current to 0 andmay be susceptible to error in estimation.• Current testing limited to a speed range up to300 Hz. For certain units, the limit is 250 Hz; all200–240 V units up to and including 2.2 kW andall 380–480 V units up to and including 4 kW.• For high-inertia applications (that is, where theload inertia is more than 30 times larger than themotor inertia), use a brake resistor to avoidovervoltage trip during high-speed engagementof the flying-start function.1-77 Compressor Start Max Speed [RPM]Range: Function:Sizerelated*[ 0 -par.4-13RPM]NOTICEParameter 1-77 Compressor Start MaxSpeed [RPM] has no effect whenparameter 1-10 Motor Construction=[1]PM, non-salient SPM.The parameter enables high starting torque.This is a function, where the current limit andtorque limit are ignored during start of themotor. The time, from the start signal is givenuntil the speed exceeds the speed set in thisparameter, becomes a “start-zone” where thecurrent limit and motoric torque limit is set towhat is maximum possible for the frequencyconverter/motor combination. This parameteris normally set to the same value asparameter 4-11 Motor Speed Low Limit [RPM].When set to zero the function is inactive.In this starting-zone, parameter 3-82 StartingRamp Up Time is active instead ofparameter 3-40 Ramp 1 Type to ensure extraacceleration during the start and to minimiseParameter Descriptions VLT® HVAC Drive FC 10248 Danfoss A/S © 03/2015 All rights reserved. MG11CE0233