Danfoss VLT AQUA Drive FC 202 Design Manual

Also see for VLT AQUA Drive FC 202: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

5 Product Features5.1 Automated Operational FeaturesAutomated operational features are active when the driveis operating. Most of them require no programming or set-up. The drive has a range of built-in protection functionsto protect itself and the motor when it runs.For details of any set-up required, in particular motorparameters, refer to the programming guide.5.1.1 Short-circuit ProtectionMotor (phase-to-phase)The drive is protected against short circuits on the motorside by current measurement in each of the 3 motorphases. A short circuit between 2 output phases causes anovercurrent in the inverter. The inverter is turned off whenthe short circuit current exceeds the permitted value(Alarm 16, Trip Lock).Mains sideA drive that works correctly limits the current it can drawfrom the supply. Still, it is recommended to use fusesand/or circuit breakers on the supply side as protection ifthere is component break-down inside the drive (firstfault). Mains side fuses are mandatory for UL compliance.NOTICETo ensure compliance with IEC 60364 for CE or NEC 2009for UL, it is mandatory to use fuses and/or circuitbreakers.Brake resistorThe drive is protected from a short circuit in the brakeresistor.Load sharingTo protect the DC bus against short circuits and the drivesfrom overload, install DC fuses in series with the loadsharing terminals of all connected units.5.1.2 Overvoltage ProtectionMotor-generated overvoltageThe voltage in the DC link is increased when the motoracts as a generator. This situation occurs in following cases:• The load rotates the motor at constant outputfrequency from the drive, that is, the loadgenerates energy.• During deceleration (ramp-down) if the inertiamoment is high, the friction is low, and the ramp-down time is too short for the energy to bedissipated as a loss throughout the drive system.• Incorrect slip compensation setting causinghigher DC-link voltage.• Back EMF from PM motor operation. If coasted athigh RPM, the PM motor back EMF canpotentially exceed the maximum voltagetolerance of the drive and cause damage. To helpprevent this situation, the value ofparameter 4-19 Max Output Frequency is automat-ically limited based on an internal calculationbased on the value of parameter 1-40 Back EMF at1000 RPM, parameter 1-25 Motor Nominal Speed,and parameter 1-39 Motor Poles.NOTICETo avoid motor overspeeds (for example, due toexcessive windmilling effects), equip the drive with abrake resistor.The overvoltage can be handled either using a brakefunction (parameter 2-10 Brake Function) and/or usingovervoltage control (parameter 2-17 Over-voltage Control).Brake functionsConnect a brake resistor for dissipation of surplus brakeenergy. Connecting a brake resistor allows a higher DC-linkvoltage during braking.AC brake is an alternative to improving braking withoutusing a brake resistor. This function controls an over-magnetization of the motor when the motor is acting as agenerator. Increasing the electrical losses in the motorallows the OVC function to increase the braking torquewithout exceeding the overvoltage limit.NOTICEAC brake is not as effective as dynamic braking with aresistor.Overvoltage control (OVC)By automatically extending the ramp-down time, OVCreduces the risk of the drive tripping due to anovervoltage on the DC-link.NOTICEOVC can be activated for a PM motor with all controlcore, PM VVC+, Flux OL, and Flux CL for PM Motors.5.1.3 Missing Motor Phase DetectionThe missing motor phase function (parameter 4-58 MissingMotor Phase Function) is enabled by default to avoid motordamage if a motor phase is missing. The default setting is1000 ms, but it can be adjusted for faster detection.Product Features Design GuideMG22B102 Danfoss A/S © 05/2017 All rights reserved. 135 5