Nidec Digitax HD M75 Series Installation And Technical Manual

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Nidec Digitax HD M75 Series Installation And Technical Manual Manual pdf 60 page image

Safety information Product information Mechanical installation Electrical installation Multi axis system design Technical data60 Digitax HD M75X Series Installation and Technical GuideIssue Number: 54.8.3 Braking resistor software overload protectionThe drive software contains an overload protection function for a braking resistor. In order to enable and set-up this function, it is necessary to enterthree values into the drive:• Braking Resistor Rated Power (10.030)• Braking Resistor Thermal Time Constant (10.031)• Braking Resistor Resistance (10.061)This data should be obtained from the manufacturer of the braking resistor.The brake resistor thermal time constant (Pr 10.031) is used to limit the energy dissipated in a resistor when braking overload energy. For the DigitaxHD M75X drives, the brake resistor thermal time constant should be set to a maximum of 2 seconds. This will protect both the drive and the brakeresistor from excessive temperatures. Full overload and continuous braking levels are achievable with this setting.Pr 10.039 gives an indication of braking resistor temperature based on a simple thermal model. Zero indicates the resistor is close to ambient and100 % is the maximum temperature the resistor can withstand. A ‘Brake Resistor’ alarm is given if this parameter is above 75 % and the braking IGBTis active. A Brake R Too Hot trip will occur if Pr 10.039 reaches 100 %, when Pr 10.037 is set to 0 (default value) or 1.If Pr 10.037 is equal to 2 or 3, a Brake R Too Hot trip will not occur when Pr 10.039 reaches 100 %, but instead the braking IGBT will be disabled untilPr 10.039 falls below 95 %. This option is intended for applications with parallel connected DC buses where there are several braking resistors, eachof which cannot withstand full DC bus voltage continuously. With this type of application it is unlikely the braking energy will be shared equallybetween the resistors because of voltage measurement tolerances within the individual drives. Therefore with Pr 10.037 set to 2 or 3, then as soon asa resistor has reached its maximum temperature the drive will disable the braking IGBT, and another resistor on another drive will take up the brakingenergy. Once Pr 10.039 has fallen below 95 % the drive will allow the braking IGBT to operate again.See the Parameter Reference Guide for more information on Pr 10.030, Pr 10.031, Pr 10.037 and Pr 10.039.This software overload protection should be used in addition to an external overload protection device.4.9 Ground leakage (PE current)The ground leakage current depends upon whether the internal EMC filter is installed or not. The drive is supplied with the filter installed. Instructionsfor disconnecting the internal filter are given in section 4.10.3 Internal EMC filter on page 65.Table 4-13 Ground leakage with and without Internal EMC filter installed* These are RMS values within a 1.5 kHz bandwidth measured with a configuration of 2 m SY cable connected to a common 4 pole motor cable at aswitching frequency of 8 kHz having the motor frame only connected to the ground potential through the motor cable. Refer to the Digitax HD M75Xseries EMC data sheet, available from the supplier of the drive.4.9.1 Use of residual current device (RCD)There are three common types of ELCB / RCD:1. AC - detects AC fault currents2. A - detects AC and pulsating DC fault currents (provided the DC current reaches zero at least once every half cycle)3. B - detects AC, pulsating DC and smooth DC fault currents• Type AC should never be used with drives• Type A can only be used with single phase drivesDriveWith internal EMCfilter connected *With internal EMCfilter disconnected *mA mAM75X-0120022 7.7 2.8M75X-0120040 7.7 2.8M75X-0120065 7.7 2.8M75X-0220090 10.9 8.9M75X-0220120 10.9 8.9M75X-0320160 8.1 1.6M75X-0140015 13.9 4.4M75X-0140035 13.9 4.4M75X-0140042 13.9 4.4M75X-0240060 16.5 6.8M75X-0240080 16.5 6.8M75X-0240105 16.5 6.8M75X-0340135 16.3 3.8M75X-0340160 16.3 3.8When the internal filter is installed the leakage current is above 3.5 mA. In this case a permanent fixed, low impedance, low inductanceground connection between the drive’s metal frame and PE must be provided, or other suitable measures taken to prevent a safety hazardoccurring if the connection is lost.WARNING