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VLT Midi Drive FC-280P4K0
Руководство по проектированию Страница: 7

Danfoss VLT Midi Drive FC-280P4K0 [7/92] Du dt conditions

7.11 dU/dt Conditions

7.12 Special Conditions

7.12.1 Manual Derating 84

7.12.2 Automatic Derating 85

Index

Contents Design Guide

Содержание

Additional resources 3
Approvals and certifications 3
Contents 3
Control structures 3
Definitions 3
Document and software version 3
Electrical installation 3
Enclosure size overview 3
Introduction 3
Pid control 3
Product overview 3
Purpose of the design guide 3
Reference handling 3
Safety 3
Application examples 4
Brake functions 4
Emc emission and immunity 4
Extreme running conditions 4
Galvanic isolation 4
Ground leakage current 4
Introduction 4
Maintenance and service for sto 4
Safe torque off installation 4
Safe torque off sto 4
Safety precautions for sto 4
Smart logic controller 4
Sto commissioning 4
Sto technical data 4
Examples 5
Fc protocol 5
Fc protocol message framing structure 5
Introduction 5
Modbus rtu 5
Modbus rtu message framing structure 5
Network configuration 5
Rs485 installation and set up 5
Acoustic noise 6
Ambient conditions 6
Cable specifications 6
Connection tightening torques 6
Control input output and control data 6
Danfoss fc control profile 6
Efficiency 6
Examples 6
Fuses and circuit breakers 6
How to access parameters 6
Mains supply 3 phase 6
Motor output and motor data 6
Ordering numbers brake resistors 6
Ordering numbers options and accessories 6
Power dependent specifications 6
Specifications 6
Type code and selection 6
Du dt conditions 7
Special conditions 7
Additional resources 8
Definitions 8
Frequency converter 8
Introduction 8
Purpose of the design guide 8
Miscellaneous 9
References 9
Approvals and certifications 11
Ce mark 11
Document and software version 11
Emc directive 11
Low voltage directive 11
Safety 12
Enclosure size depends on power range 13
Enclosure size overview 13
Product overview 13
Product overview design guide 13
A analog d digital built in brake chopper is only available on 3 phase units terminal 53 can also be used as digital input switch s801 bus terminal can be used to enable termination on the rs485 port terminals 68 and 69 refer to chapter 4 safe torque off sto for the correct sto wiring 14
Electrical installation 14
Illustration 2 basic wiring schematic drawing 14
Midi drive fc 280 14
Product overview vl 14
This section describes how to wire the frequency converter 14
Product overview design guide 15
Motor connection 16
Warning 16
Ac mains connection 17
Control terminal types 18
Illustration 2 shows the removable frequency converter connectors terminal functions and default settings are summarized in table 2 and table 2 18
Midi drive fc 280 18
Product overview vl 18
See chapter 7 control input output and control data for terminal ratings details 18
Control modes 19
Control structures 19
Notice 19
Wiring to control terminals 19
And parameter 1 00 configuration mode is set to 0 speed open loop the resulting reference from the reference handling system 21
Control principle 21
Control structure in vv 21
Fc 280 frequency converters can handle asynchronous motors and permanent magnet synchronous motors up to 22 kw 30 hp 21
In the configuration shown in illustration 2 0 parameter 1 01 motor control principle is set to 1 vv 21
Product overview design guide 21
The current sensing principle in fc 280 frequency converters is based on the current measurement by a resistor in the dc link the ground fault protection and short circuit behavior are handled by the same resistor 21
Vlt midi drive fc 280 is a general purpose frequency converter for variable speed applications the control principle is based on vv 21
Internal current control in vv 22
Local hand on and remote auto on control 22
Local reference the local reference is active when the frequency converter is operated with hand on active adjust the reference by 23
Product overview design guide 23
Reference handling 23
Remote reference the reference handling system for calculating the remote reference is shown in illustration 2 3 23
Reference limits 24
Scaling of analog and pulse references and feedback 25
Scaling of preset references and bus references 25
Case 1 positive reference with dead band digital input to trigger reverse part i illustration 2 9 shows how reference input with limits inside minimum to maximum limits clamps 26
Dead band around zero 26
Ensure that both points defining the scaling graph are in the same quadrant 26
Midi drive fc 280 26
P1 or p2 defines the size of the dead band as shown in illustration 2 8 26
Product overview vl 26
Set either the minimum reference value see table 2 for relevant parameter or maximum reference value at 0 in other words either p1 or p2 must be on the x axis in illustration 2 8 26
Sometimes the reference in rare cases also the feedback should have a dead band around 0 to ensure that the machine is stopped when the reference is near 0 26
The endpoints p1 and p2 are defined in table 2 depending on the choice of input 26
To make the dead band active and to set the amount of dead band do the following 26
Illustration 2 9 clamping of reference input with limits inside minimum to maximum 27
Product overview design guide 27
Case 2 positive reference with dead band digital input to trigger reverse part ii illustration 2 0 shows how reference input with limits outside maximum to maximum limits clamps to the input low and high limits before adding to external reference and how the external reference is clamped to maximum to maximum by the reference algorithm 28
Illustration 2 0 clamping of reference input with limits outside maximum to maximum 28
Midi drive fc 280 28
Product overview vl 28
Pid control 29
Product overview design guide 29
Speed pid control 29
The following parameters are relevant for the speed control 29
Example of programming the speed control in this example the speed pid control is used to maintain a constant motor speed regardless of the changing load on the motor the required motor speed is set via a potentiometer connected to terminal 53 the speed range is 0 1500 rpm corresponding to 0 10 v over the potentiometer a switch connected to terminal 18 controls starting and stopping the speed pid monitors the actual rpm of the motor by using a 24 v htl incremental encoder as feedback the feedback sensor is an encoder 1024 pulses per revolution connected to terminals 32 and 33 the pulse frequency range to terminals 32 and 33 is 4 hz 32 khz 30
Follow the steps in table 2 to program the speed control see explanation of settings in the programming guide in table 2 it is assumed that all other parameters and switches remain at their default setting 30
Midi drive fc 280 30
Product overview vl 30
Product overview design guide 31
Midi drive fc 280 32
Notice 32
Process pid control 32
Product overview vl 32
Table 2 shows the control configurations in which the process control is possible refer to chapter 2 control structures to see where the speed control is active 32
The process control pid works under the default parameter setting but tuning the parameters is recommended to optimize the application control performance 32
The process pid control can be used to control application parameters that can be measured by a sensor for example pressure temperature flow and affected by the connected motor through a pump fan or other connected devices 32
Process control relevant parameters 33
Product overview design guide 33
Example of process pid control 34
Product overview design guide 35
After configuring the basic settings as described in chapter 2 programming order optimize the proportional gain the integration time and the differentiation time parameter 7 33 process pid proportional gain parameter 7 34 process pid integral time and parameter 7 35 process pid differentiation time in most processes complete the following procedure 36
If necessary start stop can be activated several times to provoke a variation of the feedback signal 36
Integration time until the feedback signal stabilizes followed by an increase of 15 50 36
Midi drive fc 280 36
Notice 36
Only use parameter 7 35 process pid differentiation time for fast acting systems differentiation time the typical value is 4 times the set integration time use the differentiator when the setting of the proportional gain and the integration time has been fully optimized make sure that the lowpass filter dampens the oscillations on the feedback signal sufficiently 36
Process controller optimization 36
Product overview vl 36
Set parameter 7 33 process pid proportional gain to 0 and increase it until the feedback signal again begins to vary continuously reduce the value until the feedback signal has stabilized lower the proportional gain by 40 60 36
Set parameter 7 34 process pid integral time to 20 s and reduce the value until the feedback signal again begins to vary continuously increase the 36
Start the motor 36
Notice 37
Ziegler nichols tuning method 37
Emc emission and immunity 38
General aspects of emc emission 38
Emc emission requirements 39
Product overview design guide 39
The test results in table 2 2 have been obtained using a system with a frequency converter with the mounting plate a motor and shielded motor cables 39
To reduce the interference level from the entire system unit and installation make motor and brake cables as short as possible avoid placing cables with a sensitive signal level alongside mains motor and brake cables radio interference higher than 50 mhz airborne is especially generated by the control electronics 39
When using unshielded cables some emission requirements are not complied with although the immunity requirements are observed 39
A control box with potentiometer motor cable and motor 40
A frequency converter with options if relevant 40
A shielded control cable 40
Emc immunity requirements 40
En 61000 4 2 iec 61000 4 2 electrostatic discharges esd simulation of electrostatic discharges from human beings 40
En 61000 4 3 iec 61000 4 3 radiated immunity amplitude modulated simulation of the effects of radar and radio communication equipment and mobile communications equipment 40
En 61000 4 4 iec 61000 4 4 burst transients simulation of interference caused by switching a contactor relay or similar devices 40
En 61000 4 5 iec 61000 4 5 surge transients simulation of transients caused by for example lightning that strikes near installations 40
En 61000 4 6 iec 61000 4 6 conducted immunity simulation of the effect from radio transmission equipment joined by connection cables 40
Midi drive fc 280 40
Product overview vl 40
The immunity requirements for frequency converters depend on the environment in which they are installed the requirements for the industrial environment are higher than the requirements for the home and office environment all danfoss frequency converters comply with the requirements for the industrial environment therefore they also comply with the lower requirements for home and office environment with a large safety margin 40
The immunity requirements should follow product standard iec 61800 3 and danfoss internal standards see table 2 3 for details 40
The tests were performed in accordance with the following basic standards 40
To document immunity against burst transient from electrical phenomena the following immunity tests have been made on a system consisting of 40
Galvanic isolation 41
Ground leakage current 41
Warning 41
Brake functions 42
Mechanical holding brake 42
Notice 42
Brake resistor selection 43
Dynamic braking 43
Notice 43
Control with brake function 44
Notice 44
Smart logic controller 44
Comparators comparators are used for comparing continuous variables for example output frequency output current and analog input to fixed preset values 45
Events and actions are each numbered and linked in pairs states this means that when event 0 is fulfilled attains the value true action 0 is executed after this the conditions of event 1 are evaluated and if evaluated true action 1 is executed and so on only 1 event is evaluated at any time if an event is evaluated as false nothing happens in the slc during the current scan interval and no other events are evaluated when the slc starts it evaluates event 0 and only event 0 each scan interval only when event 0 is evaluated true the slc executes action 0 and starts evaluating event 1 it is possible to program 1 20 events and actions when the last event action has been executed the sequence starts over again from event 0 action 0 illustration 2 4 shows an example with 3 event actions 45
Extreme running conditions 45
Illustration 2 3 associated action 45
Illustration 2 4 sequence with 3 events actions 45
Illustration 2 5 comparators 45
Illustration 2 6 logic rules 45
Logic rules combine up to 3 boolean inputs true false inputs from timers comparators digital inputs status bits and events using the logical operators and or and not 45
Product overview design guide 45
Short circuit motor phase to phase the frequency converter is protected against short circuits by current measurement in each of the 3 motor phases or in the dc link a short circuit between 2 output phases causes an overcurrent in the frequency converter the frequency converter is turned off individually when the short circuit current exceeds the permitted value alarm 16 trip lock 45
Switching on the output switching on the output between the motor and the frequency converter is fully allowed and does not damage the frequency converter however fault messages may appear 45
Motor thermal protection 46
Application examples 47
Closed loop drive system 47
Encoder connection 47
Encoder direction 47
Introduction 47
Application examples 48
Application examples vl 48
If terminal 12 and 27 are not connected set parameter 5 12 terminal 27 digital input to 0 no operation 48
Midi drive fc 280 48
Notice 48
Application examples design guide 49
Start stop 49
Application examples vl 50
External alarm reset 50
Midi drive fc 280 50
Motor thermistor 50
Notice 50
To meet pelv insulation requirements use reinforced or double insulation on the thermistors 50
Safe torque off sto 51
Notice 52
Warning 52
Notice 53
Warning 53
Maintenance and service for sto 54
Notice 54
Test for sto applications in automatic restart mode 54
Test for sto applications in manual restart mode 54
A safe error for example output in safe state is repaired within 8 hours 55
Failure rates are based on the siemens sn29500 database 55
Failure rates are constant wear out mechanisms are not included 55
For each channel the safety related components are considered to be of type a with a hardware fault tolerance of 0 55
Midi drive fc 280 takes 10 of the total failure budget for an sil2 safety loop 55
Mounted verify that alarm 188 sto function fault is logged in parameter 15 30 alarm log error code 55
No torque output is the safe state 55
Reapply 24 v supply to terminal 37 and verify that resetting the alarm is successful 55
Reapply 24 v supply to terminal 38 and verify that resetting the alarm is successful 55
Remove the 24 v supply for terminal 38 and verify that the lcp shows alarm 188 sto function fault if the lcp is mounted if the lcp is not 55
Safe torque off sto design guide 55
Sto technical data 55
The failure modes effects and diagnostic analysis fmeda is performed based on the following assumptions 55
The stress levels are average for an industrial environment and the working temperature of components is up to 85 c 185 f 55
Introduction 56
Network connection 56
Notice 56
Overview 56
Rs485 installation and set up 56
Emc precautions 57
Fc protocol 57
Hardware set up 57
Notice 57
Overview 57
Parameter settings for modbus communication 57
Content of a character byte 58
Fc protocol message framing structure 58
Fc with modbus rtu 58
Network configuration 58
Telegram length lge 58
Telegram structure 58
Address format 1 126 59
Bit 0 6 0 broadcast 59
Bit 0 6 frequency converter address 1 126 59
Bit 7 1 address format 1 126 active 59
Bits 12 15 transfer parameter commands from master to slave and return processed slave responses to the master 59
Control word and reference value from master to slave 59
Data control byte bcc 59
Frequency converter address adr 59
If the command cannot be performed the slave sends this response 0111 command cannot be performed and issues the following fault report in table 5 59
Parameter block the parameter block is used to transfer parameters between master and slave the data block is made up of 12 bytes 6 words and also contains the process block 59
Parameter command and response ak 59
Parameter number pnu 59
Process block pcd the pcd is made up of a data block of 4 bytes 2 words and contains 59
Rs485 installation and set design guide 59
Status word and present output frequency from slave to master 59
Text block the text block is used to read or write texts via the data block 59
The 3 types of telegram are 59
The checksum is calculated as an xor function before the first byte in the telegram is received the calculated checksum is 0 59
The data field 59
The pke field 59
The pke field contains 2 subfields 59
The slave returns the address byte unchanged to the master in the response telegram 59
The structure of data blocks depends on the type of telegram there are 3 telegram types and the type applies for both control telegrams master slave and response telegrams slave master 59
Bits 0 11 transfer parameter numbers the function of the relevant parameter is defined in the parameter description in the vl 60
Byte of the telegram lge when using text transfer the index character indicates whether it is a read or a write command 60
Conversion 60
Data types supported by the frequency converter 60
Index ind 60
Midi drive fc 280 60
Midi drive fc 280 programming guide 60
Only the low byte is used as an index 60
Parameter 0 01 language select the data value by entering the value in the pwe block serial communication is only capable of reading parameters containing data type 9 text string 60
Parameter 15 40 fc type to parameter 15 53 power card serial number contain data type 9 for example read the unit size and mains voltage range in parameter 15 40 fc type when a text string is transferred read the length of the telegram is variable and the texts are of different lengths the telegram length is defined in the 60
Parameter 4 12 motor speed low limit hz has a conversion factor of 0 to preset the minimum frequency to 10 hz transfer the value 100 a conversion factor of 0 means that the value transferred is multiplied by 0 the value 100 is thus perceived as 10 60
Parameter number pnu 60
Parameter value pwe 60
Rs485 installation and set vl 60
The index is used with the parameter number to read write access parameters with an index for example parameter 15 30 alarm log error code the index consists of 2 bytes a low byte and a high byte 60
The parameter value block consists of 2 words 4 bytes and the value depends on the defined command ak the master prompts for a parameter value when the pwe block contains no value to change a parameter value write write the new value in the pwe block and send from the master to the slave 60
The programming guide contains the descriptions of attributes of each parameter parameter values are transferred as whole numbers only conversion factors are used to transfer decimals 60
To read a text via the pwe block set the parameter command ak to f hex the index character high byte must be 4 60
Unsigned means that there is no operational sign in the telegram 60
When a slave responds to a parameter request read command the present parameter value in the pwe block is transferred and returned to the master if a parameter contains several data options for example 60
Examples 61
Notice 61
Process words pcd 61
Reading a parameter value 61
Writing a parameter value 61
Frequency converter with modbus rtu 62
Modbus rtu 62
Network configuration 62
Overview 62
Prerequisite knowledge 62
Address field 63
Function field 63
Introduction 63
Modbus rtu message framing structure 63
Modbus rtu telegram structure 63
Start stop field 63
Coil or register addresses 64
Coil register addressing 64
Crc check field 64
Data field 64
In modbus all data is organized in coils and holding registers coils hold a single bit whereas holding registers hold a 2 byte word that is 16 bits all data addresses in modbus telegrams are referenced to 0 the first occurrence of a data item is addressed as item number 0 for example the coil known as coil 1 in a programmable controller is addressed as coil 0000 in the data address field of a modbus telegram coil 127 decimal is addressed as coil 007ehex 126 decimal holding register 40001 is addressed as register 0000 in the data address field of the telegram the function code field already specifies a holding register operation therefore the 4xxxx reference is implicit holding register 40108 is addressed as register 006bhex 107 decimal 64
Midi drive fc 280 64
Rs485 installation and set vl 64
Telegrams include an error checking field operating based on a cyclic redundancy check crc method the crc field checks the contents of the entire telegram it is applied regardless of any parity check method used for the individual characters of the telegram the transmitting device calculates the crc value and appends the crc as the last field in the telegram the receiving device recalculates a crc during receipt of the telegram and compares the calculated value to the actual value received in the crc field 2 unequal values result in bus timeout the error checking field contains a 16 bit binary value implemented as 2 8 bit bytes after the implementation the low order byte of the field is appended first followed by the high order byte the crc high order byte is the last byte sent in the telegram 64
The count of actual data bytes in the field 64
The data field is constructed using sets of 2 hexadecimal digits in the range of 00 ff hexadecimal these digits are made up of 1 rtu character the data field of telegrams sent from a master to a slave device contains additional information which the slave must use to perform accordingly 64
The information can include items such as 64
The quantity of items to be handled 64
Rs485 installation and set design guide 65
Examples reading parameter 3 12 catch up slow down value 16 bit the holding register 3120 holds the parameters value a value of 1352 decimal means that the parameter is set to 12 2 66
For a full explanation of the structure of an exception code response refer to chapter 5 function field 66
For information on the parameters size and conversion index see the vl 66
Function codes supported by modbus rtu 66
How to access parameters 66
How to control the frequency converter 66
Midi drive fc 280 66
Midi drive fc 280 programming guide 66
Modbus exception codes 66
Modbus rtu supports use of the following function codes in the function field of a telegram 66
Parameter handling 66
Reading parameter 3 14 preset relative reference 32 bit the holding registers 3410 and 3411 hold the parameters values a value of 11300 decimal means that the parameter is set to 1113 0 66
Rs485 installation and set vl 66
The pnu parameter number is translated from the register address contained in the modbus read or write telegram the parameter number is translated to modbus as 10 x parameter number decimal 66
This section describes codes which can be used in the function and data fields of a modbus rtu telegram 66
Conversion factor 67
Examples 67
Ind index 67
Notice 67
Parameter values 67
Read coil status 01 hex 67
Storage of data 67
Text blocks 67
Coil addresses start at 0 that is coil 17 is addressed as 16 68
Description this function forces each coil in a sequence of coils to either on or off when broadcasting the function forces the same coil references in all attached slaves 68
Description this function forces the coil to either on or off when broadcast the function forces the same coil references in all attached slaves 68
Description this function reads the contents of holding registers in the slave 68
Example read parameter 3 03 maximum reference register 03030 68
Force write multiple coils 0f hex 68
Force write single coil 05 hex 68
Midi drive fc 280 68
Notice 68
Query the query telegram specifies the coil 65 parameter write control to be forced coil addresses start at 0 that is coil 65 is addressed as 64 force data 00 00 hex off or ff 00 hex on 68
Query the query telegram specifies the coils 17 32 speed setpoint to be forced 68
Query the query telegram specifies the starting register and quantity of registers to be read register addresses start at 0 that is registers 1 4 are addressed as 0 3 68
Read holding registers 03 hex 68
Response the normal response is an echo of the query returned after the coil state has been forced 68
Response the normal response returns the slave address function code starting address and quantity of coils forced 68
Rs485 installation and set vl 68
Byte contains the high order bits and the 69
Contains the low order bits 69
Description this function presets a value into a single holding register 69
Description this function presets values into a sequence of holding registers 69
Example hex 000088b8 35 00 35 hz 69
Example write to parameter 1 00 configuration mode register 1000 69
Preset multiple registers 10 hex 69
Preset single register 06 hex 69
Query the query telegram specifies the register reference to be preset register addresses start at 0 that is register 1 is addressed as 0 69
Query the query telegram specifies the register references to be preset register addresses start at 0 that is register 1 is addressed as 0 example of a request to preset 2 registers set parameter 1 24 motor current to 738 7 8 a 69
Response the normal response is an echo of the query returned after the register contents have been passed 69
Response the normal response returns the slave address function code starting address and quantity of registers preset 69
Response the register data in the response telegram is packed as 2 bytes per register with the binary contents right justified within each byte for each register the 69
Rs485 installation and set design guide 69
8 10 protocol fc profile 70
Control word according to fc profile 70
Danfoss fc control profile 70
Notice 70
Status word according to fc profile 71
Bus speed reference value 73
Illustration 5 5 actual output frequency mav 73
Illustration 5 6 reference and mav 73
Rs485 installation and set design guide 73
Speed reference value is transmitted to the frequency converter in a relative value in the value is transmitted in the form of a 16 bit word the integer value 16384 4000 hex corresponds to 100 negative figures are formatted using 2 s complement the actual output frequency mav is scaled in the same way as the bus reference 73
The reference and mav are scaled as follows 73
Midi drive fc 280 74
Ordering numbers options and accessories 74
Type code and selection 74
Type code and selection vl 74
Danfoss offers a wide variety of different resistors that are specially designed for our frequency converters see chapter 2 control with brake function for the dimensioning of brake resistors this section lists the ordering numbers for the brake resistors 75
Ordering numbers brake resistors 75
Ordering numbers brake resistors 10 75
Type code and selection design guide 75
Midi drive fc 280 76
Ordering numbers brake resistors 40 76
Type code and selection vl 76
Power dependent specifications 77
Specifications 77
Specifications design guide 77
Mains supply 3 phase 78
Mains supply l1 l2 l3 supply terminals l1 l2 l3 78
Maximum imbalance temporary between mains phases 3 of rated supply voltage 78
Midi drive fc 280 78
Specifications vl 78
Supply frequency 50 60 hz 5 78
Supply voltage 380 480 v 15 25 78
Switching on input supply l1 l2 l3 power ups 11 22 kw maximum 1 time minute 78
Switching on input supply l1 l2 l3 power ups 7 kw maximum 2 times minute 78
The frequency converter can run at 25 input voltage with reduced performance the maximum output power of the frequency converter is 75 if input voltage is 25 and 85 if input voltage is 15 full torque cannot be expected at mains voltage lower than 10 below the lowest rated supply voltage of the frequency converter 78
The unit is suitable for use on a circuit capable of delivering less than 5000 rms symmetrical amperes 480 v maximum 78
True power factor λ 0 nominal at rated load 78
Ambient conditions 79
Motor output and motor data 79
Cable specifications 80
Control input output and control data 80
High altitude 81
Notice 81
Caution 83
Notice 83
Efficiency 84
Acoustic noise 85
Affect the service life of the motor if the peak voltage is too high motors without phase coil insulation are affected the longer the motor cable the higher the rise time and peak voltage 85
Dc intermediate circuit coils 85
Du dt conditions 85
In the motor voltage before it stabilizes itself at a level depending on the voltage in the dc link the rise time and the peak voltage 85
Inductance 85
Integral fan 85
Rfi filter choke 85
Specifications design guide 85
Switching of the igbts cause peak voltage on the motor terminals the fc 280 complies with iec 60034 25 regarding motors designed to be controlled by frequency converters the fc 280 also complies with iec 60034 17 regarding norm motors controlled by frequency converters the following du dt data are measured at the motor terminal side 85
The acoustic noise from the frequency converter comes from 3 sources 85
The cross section of the motor cable 85
The length of the motor cable 85
The motor cable type 85
The natural induction causes an overshoot 85
The typical values measured at a distance of 1 m 3 ft from the unit 85
When a transistor in the frequency converter bridge switches the voltage across the motor increases by a du dt ratio depending on the following factors 85
Whether the motor cable is shielded or not 85
Air pressure for installation at altitudes above 1000 m 3281 ft 86
Ambient temperature above 45 c 113 f for details see illustration 7 illustration 7 illustration 7 illustration 7 and illustration 7 86
Manual derating 86
Manual derating must be considered for 86
Midi drive fc 280 86
Motor speed at continuous operation at low rpm in constant torque applications 86
Special conditions 86
Specifications vl 86
Under some special conditions where the operation of the frequency converter is challenged consider derating in some conditions derating must be done manually in other conditions the frequency converter automatically performs a degree of derating when necessary derating is done to ensure the performance at critical stages where the alternative could be a trip 86
As a response to a critical level the frequency converter adjusts the switching frequency 87
Automatic derating 87
Critical high temperature on the heat sink 87
High motor load 87
Low motor speed 87
Protection signals overvoltage undervoltage overcurrent ground fault and short circuit are triggered 87
Specifications design guide 87
The frequency converter constantly checks for critical levels 87
Index design guide 91
Mg07b102 92
R0142 mg07b102 03 2016 92

Danfoss VLT Midi Drive FC-280P4K0 [7/92] Du dt conditions

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