Danfoss VLT HVAC Design Manual

Also see for VLT HVAC: Instructions Operating instructions Instruction Operating instructions Instruction manual

Contents

Danfoss VLT HVAC Design Manual Manual pdf 44 page image

1. Power supply (SMPS) incl. signal isolation of UDC, indicating theintermediate current voltage.2. Gate drive that runs the IGBTs (trigger transformers/opto-cou-plers).3. Current transducers.4. Opto-coupler, brake module.5. Internal inrush, RFI, and temperature measurement circuits.6. Custom relays.Illustration 2.10: Galvanic isolationThe functional galvanic isolation (a and b on drawing) is for the 24 V back-up option and for the RS 485 standard bus interface.Installation at high altitude:380 - 500 V, enclosure A, B and C: At altitudes above 2 km, please contact Danfoss regarding PELV.380 - 500V, enclosure D, E and F: At altitudes above 3 km, please contact Danfoss regarding PELV.525 - 690 V: At altitudes above 2 km, please contact Danfoss regarding PELV.2.11 Earth Leakage CurrentTouching the electrical parts may be fatal - even after the equipment has been disconnected from mains.Also make sure that other voltage inputs have been disconnected, such as load sharing (linkage of DC intermediate circuit), as well asthe motor connection for kinetic back-up.Before touching any electrical parts, wait at least the amount of time indicated in theSafety Precautions section.Shorter time is allowed only if indicated on the nameplate for the specific unit.Leakage CurrentThe earth leakage current from the frequency converter exceeds 3.5 mA. To ensure that the earth cable has a good mechanicalconnection to the earth connection (terminal 95), the cable cross section must be at least 10 mm 2 or 2 rated earth wires terminatedseparately.Residual Current DeviceThis product can cause a d.c. current in the protective conductor. Where a residual current device (RCD) is used for protection in caseof direct or indirect contact, only an RCD of Type B is allowed on the supply side of this product. Otherwise, another protective measureshall be applied, such as separation from the environment by double or reinforced insulation, or isolation from the supply system by atransformer. See also RCD Application Note MN.90.GX.02.Protective earthing of the frequency converter and the use of RCD's must always follow national and local regulations.2 Introduction to VLT HVAC Drive VLT® HVAC Drive Design Guide44 MG.11.B9.02 - VLT ® is a registered Danfoss trademark2