Frequency inverter M-Max - Moeller

Engineering04/10 MN04020001Z-ENSafety and switchingFuses and cable cross-sectionsThe fuses and wire cross-sections allocated for power-sideconnections depend on the rated mains current I LN of thefrequency inverter (without mains reactor).h Caution!When selecting the cable cross-section, take the voltagedrop under load conditions into account.The consideration of other standards (e.g. VDE 0113 orVDE 0289) is the responsibility of the user.The recommended fuses and their assignment to the frequencyinverters are listed in page 157 the appendix.The national and regional standards (for example VDE 0113, EN60204) must be observed and the necessary approvals (forexample UL) at the site of installation must be fulfilled.When the device is operated in a UL-approved system, use onlyUL-approved fuses, fuse bases and cables.The leakage currents to ground (to EN 50178) are greater than3.5 mA. The connection terminals marked PE and the housingmust be connected with the ground circuit.The leakage currents for the individual performance variables arelisted in the appendix on page 147 ff.h Caution!The specified minimum PE conductor cross-sections (EN50178, VDE 0160) must be maintained.hChoose the cross-section of the PE conductor in the motorlines at least as large as the cross-section of the phaselines (U, V, W).Cables and fusesThe cross-sections of the cables and line protection fuses usedmust correspond with local standards.For an installation in accordance with UL guidelines, the fuses andcopper cable that are UL-approved and have a heat-resistance of+60/75 °C are to be used.Use power cables with insulation according to the specified mainsvoltages for the permanent installation. A shielded cable is notrequired on the mains side.A completely (360°) shielded low impedance cable on the motorside is required. The length of the motor cable depends on theRFI class and must not exceed 30 m for the M-Max TM .Residual-current device (RCD)RCD (Residual Current Device): Residual current device, residualcurrent circuit breaker (FI circuit breaker)Residual current circuit breakers protect persons and animals fromthe existence (not the origination) of impermissibly high contactvoltages. The prevent dangerous, in cases deadly injuries causedby electrical accidents and also serve as fire prevention.j Warning!With frequency inverters, only AC/DC sensitive residualcurrent circuit breakers (RCD type B) are to be used(EN 50178, IEC 755).Identification on the residual-current circuit-breakersAC/DC sensitive(RCD, type B)Frequency inverters work internally with rectified AC currents. If anerror occurs, the DC currents can block an RCD circuit breaker oftype A from triggering and therefore disable the protectivefunctionality.h Caution!Debounced inputs may not be used in the safetycircuit diagram.Residual current circuit breakers (RCD) are only to beinstalled between the AC power supply network and thefrequency inverter.Safety-relevant leakage currents can occur while handling andwhen operating the frequency inverter, if the frequency inverter isnot grounded (because of a fault).Leakage currents to ground are mainly caused by foreigncapacities with frequency inverters; between the motor phasesand the shielding of the motor cable and via the Y-capacitors ofthe noise filter. The size of the leakage current is mainly dependentupon the:• length of the motor cable,• shielding of the motor cable,• height of the pulse frequency (switching frequency of theinverter),• design of the noise filter,• Grounding measures at the site of the motor.hhThe leakage current to ground is greater than 3.5 mA witha frequency inverter. Based on the requirements ofEN 50178, an increased ground (PE) has to be connected.The cable cross-section must be at least 10 mm 2 orconsist of two separately connected ground cables.As long as you use residual current circuit breakers, theymust be suitable for:• the protection of installations with DC currentcomponent in case of fault scenario (RCD type B),• high leakage currents (300 mA),• brief discharges of pulse current spikes.26