Danfoss VLT Refrigeration Drive FC 103 Design Manual

Also see for VLT FC 103: Service guide Installation guide Installation guide Operating guide Installation guide

Contents

Danfoss VLT Refrigeration Drive FC 103 Design Manual Manual pdf 55 page image

Higher losses• Harmonics reduce the active power, apparentpower, and reactive power.• Distort electrical loads resulting in audibleinterference in other devices, or, in worst case,even destruction.• Shorten the lifetime of devices as a result ofheating.NOTICEExcessive harmonic content puts a load on power factorcorrection equipment and may even cause itsdestruction. For this reason, provide chokes for powerfactor correction equipment when excessive harmoniccontent is present.3.4.3 Analysing Mains InterferenceTo avoid impairment of mains power quality, variousmethods are available for analysing systems or devices thatgenerate harmonic currents. Mains analysis programs, suchas harmonic calculation software (HCS), analyse systemdesigns for harmonics. Specific countermeasures can betested beforehand and ensure subsequent system compati-bility.For analysing mains systems, go tohttp://www.danfoss-hcs.com/Default.asp?LEVEL=START for software download.NOTICEDanfoss has a high level of EMC expertise and providesEMC analyses with detailed evaluation or mainscalculations to customers in addition to training courses,seminars, and workshops.3.4.4 Options for Reducing MainsInterferenceGenerally speaking, mains interference from frequencyconverters is reduced by limiting the amplitude of pulsedcurrents. This reduction improves the power factor λ(lambda).Several methods are recommended to avoid mainsharmonics:• Input chokes or DC-link chokes in the frequencyconverters.• Passive filters.• Active filters.• Slim DC links.• Active front end and low harmonic drives.• Rectifiers with 12, 18, or 24 pulses per cycle.3.4.5 Radio Frequency InterferenceFrequency converters generate radio frequencyinterference (RFI) due to their variable-width currentpulses. Frequency converters and motor cables radiatethese components and conduct them into the mainssystem.RFI filters are used to reduce this interference on themains. They provide noise immunity to protect devicesagainst high-frequency conducted interference. They alsoreduce interference emitted to the mains cable or radiationfrom the mains cable. The filters are intended to limitinterference to a specified level. Built-in filters are oftenstandard equipment rated for specific immunity.NOTICEAll VLT® Refrigeration Drive FC 103 frequency convertersare equipped with integrated mains interference chokesas standard.3.4.6 Classification of the Operating SiteKnowing the requirements for the environment thefrequency converter is intended to operate in is the mostimportant factor regarding EMC compliance.3.4.6.1 Environment 1/Class B: ResidentialOperating sites connected to the public low-voltage powergrid, including light industrial areas, are classified asEnvironment 1/Class B. They do not have their own highvoltage or medium-voltage distribution transformers for aseparate mains system. The environment classificationsapply both inside and outside buildings. Some generalexamples are:• Business areas.• Residential buildings.• Restaurants.• Car parks.• Entertainment facilities.3.4.6.2 Environment 2/Class A: IndustrialIndustrial environments are not connected to the publicpower grid. Instead, they have their own high voltage ormedium-voltage distribution transformers. Theenvironment classifications apply both inside and outsidethe buildings.They are defined as industrial and are characterised byspecific electromagnetic conditions:System Integration Design GuideMG16G202 Danfoss A/S © 08/2015 All rights reserved. 533 3