CI-TI Contactors - VLT Frequency Converters

MN.90.K1.02 - VLT is a registered Danfoss trademark 1

Description This data sheet is based on tests made in co-operation with Contactor Business from Danfoss Automatic Division and Danfoss Drives A/S. The purpose of this data sheet is to make it easy, comfortable and without problems for our customers to choose the right contactor for a frequency converter - especially Danfoss VLT. Supply side When choosing a contactor for connection to the frequency converter's input, it is the nominal input current (I L,N ) of the frequency converter that is the criteria for dimensioning the contactor and not as usual the full load current of the motor. Most of the Danfoss frequency converters have built-in NTC-resistors or PTC-resistors in the intermediate circuit of a so-called "soft charge" circuit to limit the starting current. This can advantageously be used for the dimensioning of the contactor, as it can be recommended to choose from the the contactor's I th value (AC-, because of the limitation of the starting current and to compare the contactor's I th value with the frequency converter's nominal input current (I L,N ). I th! I L,N Output side Couplings Overcurrent protection When choosing a contactor for connection to the output side of the frequency converter, terminal U, V, W, the max. output current I VLT, MAX of the frequency converter must be taken into account, compared to six times the contactors AC-3 value and its thermal current value (I th ). I th! I L,N og 6 x AC-3! I VLT, MAX If the contactor cuts out on low frequencies, the lifetime will be reduced according to the curve shown. Lifetime curve Frequency [Hz] Parallel operation If several frequency converters are connected to the supply side with one common contactor, the contactor must be chosen from the recommended contactor sizes for the individual frequency converter type and be calculated according to the formula below: If several motors are connected to the same frequency converter, the individual motor can be protected against overcurrent by choosing a thermal overload relay type TI with a current range covering the motor full load current. ΣCI VLT = CI x number of phases VLT 3 phases 2 MN.90.K1.02 VLT is a registered Danfoss trademark

Short circuit protection It cannot be recommended to mount circuit breakers for short circuit protection or overcurrent protection between frequency converter and motor, as the current harmonicscreate extra heat in the circuit breaker's electromagnetic part which then influences the thermal part, by which unexpected cutout may happen. Recommended dimensioning of the contactor size type CI for the VLT series 2800 VLT Supply Min. recommended contactor size Type V 2803 CI 6 037H0015xx or CI 4-5 037H3114xx 2805 CI 6 037H0015xx or CI 4-5 037H3114xx 2807 1 x 220-240 CI 6 037H0015xx or CI 4-5 037H3114xx 2811 CI 6 037H0015xx or CI 4-5 037H3114xx 2815 CI 6 037H0015xx or CI 4-5 037H3114xx 2803 CI 6 037H0015xx or CI 4-5 037H3114xx 2805 CI 6 037H0015xx or CI 4-5 037H3114xx 2807 3 x 200-240 CI 6 037H0015xx or CI 4-5 037H3114xx 2811 CI 6 037H0015xx or CI 4-5 037H3114xx 2815 CI 6 037H0015xx or CI 4-5 037H3114xx 2822 CI 6 037H0015xx or CI 4-5 037H3114xx 2805 CI 6 037H0015xx or CI 4-5 037H3114xx 2807 CI 6 037H0015xx or CI 4-5 037H3114xx 2811 CI 6 037H0015xx or CI 4-5 037H3114xx 2815 3 x 380-480 CI 6 037H0015xx or CI 4-5 037H3114xx 2822 CI 6 037H0015xx or CI 4-5 037H3114xx 2830 CI 6 037H0015xx or CI 4-5 037H3114xx 2840 CI 6 037H0015xx or CI 4-5 037H3114xx The contactors are chosen acc. to the AC-1 value (I th ) at max. 40 0 C. Recommended dimensioning of contactor type CI for the FCM 300 series FCM Supply Min. recommended contactor size Type V 305 CI 6 037H0015xx or CI 4-5 037H3114xx 307 CI 6 037H0015xx or CI 4-5 037H3114xx 311 CI 6 037H0015xx or CI 4-5 037H3114xx 315 CI 6 037H0015xx or CI 4-5 037H3114xx 322 3 x 380-480 CI 6 037H0015xx or CI 4-5 037H3114xx 330 CI 6 037H0015xx or CI 4-5 037H3114xx 340 CI 6 037H0015xx or CI 4-5 037H3114xx 355 CI 6 037H0015xx or CI 4-5 037H3114xx 375 CI 6 037H0015xx or CI 4-5 037H3114xx Contactors chosen acc. to the AC-1 value (I th ) at max 40 0 C. MN.90.K1.02 - VLT is a registered Danfoss trademark 3

When ordering contactors, an appendix no. must be added after the code no. acc. to the table below. For other coil voltages, please contact Danfoss. Coil voltage tabel for contactors Coil voltage 220/60 220-230/50 220-230/50-60 240/50 380-400/50 415/50 380-400/50-60 440/60 Appendix 29 31 32 33 37 38 39 Not CI 4-5 Recommended dimensioning of contactors size type CI for the VLT series 5000 VLT Supply Min. recommended contactor size Type V 5001 CI 6 037H0015xx or CI 4-5 037H3114xx 5002 CI 6 037H0015xx or CI 4-5 037H3114xx 5003 CI 6 037H0015xx or CI 4-5 037H3114xx 5004 CI 6 037H0015xx or CI 4-5 037H3114xx 5005 CI 6 037H0015xx or CI 4-5 037H3114xx 5006 CI 6 037H0015xx or CI 4-5 037H3114xx 5008 CI 16 037H0041xx 5011 3 x 200-240 CI 32 037H0061xx 5016 CI 32 037H0061xx 5022 CI 37 037H0056xx 5027 CI 61 037H3061xx 5032 CI 85 037H3205xx 5042 CI 85 037H3205xx 5052 CI 141 037H3339xx or CI 140 EI 037H3217xx 5001 CI 6 037H0015xx or CI 4-5 037H3114xx 5002 CI 6 037H0015xx or CI 4-5 037H3114xx 5003 CI 6 037H0015xx or CI 4-5 037H3114xx 5004 CI 6 037H0015xx or CI 4-5 037H3114xx 5005 CI 6 037H0015xx or CI 4-5 037H3114xx 5006 CI 6 037H0015xx or CI 4-5 037H3114xx 5008 CI 6 037H0015xx or CI 4-5 037H3114xx 5011 CI 6 037H0015xx or CI 4-5 037H3114xx 5016 CI 16 037H0041xx 5022 CI 16 037H0041xx 5027 3 x 380-500 CI 32 037H0061xx 5032 CI 32 037H0061xx 5042 CI 37 037H0056xx 5052 CI 61 037H3061xx 5060 CI 85 037H3205xx 5075 CI 85 037H3205xx 5100 CI 141 037H3339xx or CI 140 EI 037H3217xx 5125 CI 210 EI 037H3259xx 5150 CI 210 EI 037H3259xx 5200 CI 250 EI 037H3267xx 5250 CI 300 EI 037H3269xx 5300 CI 300 EI 037H3269xx 5350 CI 300 EI 037H3279xx as net contactor only The contactors are chosen acc. to the AC-1 value (I th ) at max. 40 0 C. 4 MN.90.K1.02 VLT is a registered Danfoss trademark

When ordering contactors, an appendix no. must be added after the code no. acc. to the table below. For other coil voltages, please contact Danfoss. Coil voltage table for contactors Coil voltage 220/60 220-230/50 220-230/50-60 240/50 380-400/50 415/50 380-400/50-60 440/60 Appendix 29 31 32 3) 33 37 38 39 2)4) Not CI 4-5 2) Not CI 6, CI 16, CI 32, CI 37, CI 85 og CI 141 3) Not CI 85 og CI 141 4) Only CI 61, CI 140 EI, CI 210 EI, CI 250 EI, CI 300 EI and CI 420 EI Recommended dimensioning of contactors size type CI for the VLT series 6000 VLT Supply Min. recommended contactor size Type V 6002 CI 6 037H0015xx or CI 4-5 037H3114xx 6003 CI 6 037H0015xx or CI 4-5 037H3114xx 6004 CI 6 037H0015xx or CI 4-5 037H3114xx 6005 CI 6 037H0015xx or CI 4-5 037H3114xx 6006 CI 6 037H0015xx or CI 4-5 037H3114xx 6008 CI 9 037H0021xx or CI 4-9 037H3116xx 6011 CI 16 037H0041xx 6016 3 x 200-240 CI 32 037H0061xx 6022 CI 32 037H0061xx 6027 CI 37 037H0056xx 6032 CI 61 037H3061xx 6042 CI 85 037H3205xx 6052 CI 85 037H3205xx 6062 CI 141 037H3339xx or CI 140 EI 037H3217xx 6002 CI 6 037H0015xx or CI 4-5 037H3114xx 6003 CI 6 037H0015xx or CI 4-5 037H3114xx 6004 CI 6 037H0015xx or CI 4-5 037H3114xx 6005 CI 6 037H0015xx or CI 4-5 037H3114xx 6006 CI 6 037H0015xx or CI 4-5 037H3114xx 6008 CI 6 037H0015xx or CI 4-5 037H3114xx 6011 CI 6 037H0015xx or CI 4-5 037H3114xx 6016 CI 9 037H0021xx or CI 4-9 037H3116xx 6022 CI 16 037H0041xx 6027 CI 16 037H0041xx 6032 3 x 380-460 CI 32 037H0061xx 6042 CI 32 037H0061xx 6052 CI 37 037H0056xx 6062 CI 61 037H3061xx 6075 CI 85 037H3205xx 6100 CI 85 037H3205xx 6125 CI 141 037H3339xx or CI 140 EI 037H3217xx 6150 CI 141 037H3339xx or CI 140 EI 037H3217xx 6175 CI 250 EI 037H3267xx 6225 CI 250 EI 037H3267xx 6275 CI 300 EI 037H3269xx 6350 CI 300 EI 037H3269xx 6400 CI 420 EI 037H3279xx as net contactor only The contactors are chosen acc. to the AC-1 value (I th ) at max. 40 0 C. MN.90.K1.02 - VLT is a registered Danfoss trademark 5

Coil voltage table for contactors Coil voltage 220/60 220-230/50 220-230/50-60 240/50 380-400/50 415/50 380-400/50-60 440/60 Appendix 29 31 32 3) 33 37 38 39 2)4) Not CI 4-5 2) Not CI 6, CI 16, CI 32, CI 37, CI 85 og CI 141 3) Not CI 85 og CI 141 4) Only CI 61, CI 140 EI, CI 210 EI, CI 250 EI, CI 300 EI and CI 420 EI Thermal overload relays for contactors type CI 4-5 and CI 6 - CI 30 Ordering Thermal overload relays TI 9C for mini contactors CI 4 Range Motor starters Code no. Type A 0.13-20 047H3060 0.19-0.29 047H3061 0.27-0.42 047H3062 0.4-0.62 047H3063 0.6-0.92 047H3064 0.85-1.3 047H3065 TI 9C 1.2-1.9 047H3066 1.8-2.8 047H3067 2.7-4.2 047H3068 4.0-6.2 047H3069 6.0-9.2 047H3070 Thermal overload realys TI 16C, TI 25C and TI 30C for contactors CI 6-30 Range Motor starters Code no. Type A 0.13-0.20 047H0200 0.19-0.29 047H0201 0.27-0.42 047H0202 0.4-0.62 047H0203 0.6-0.92 047H0204 0.85-1.3 047H0205 TI 16C 1.2-1.9 047H0206 1.8-2.8 047H0207 2.7-4.2 047H0208 4.0-6.2 047H0209 6.0-9.2 047H0210 8.0-12.0 047H0211 11.0-16.0 047H0212 15.0-20.0 047H0213 19.0-25.0 047H0214 TI 25C 24.0-32.0 047H0215 TI 30C 6 MN.90.K1.02 VLT is a registered Danfoss trademark

Thermal overload relays for contactors type CI 32 - CI 420 EI Ordering Thermal overload relays TI 80, TI 86, TI 90 and TI 110 for contactors CI 32-105 Range Motor starters Code no. Type A 16.0-23.0 047H1013 22.0-32.0 047H1014 30.0-45.0 047H1015 TI 80 42.0-63.0 047H1016 60.0-80.0 047H1017 74.0-85.0 047H1018 TI 86 68.0-90.0 047H3010 TI 90 85.0-110.0 047H3011 TI 110 Conductor rail set 037H0108 Electronic thermal overload relay TI 180 E - 630 E for contactors CI 85-420 EI Supply voltage Range With remote reset Without remote reset motor starters Code no. Code no. Type U S 24 V, 50/60 Hz 047H3004 047H3013 110 V, 50/60 Hz 047H3005 047H3014 220-230 V, 50/60 Hz 20-180 A 047H3006 047H3015 TI 180 E 240 V, 50/60 Hz 047H3007 047H3016 380-400 V, 50/60 Hz 047H3008 047H3017 415 V, 50/60 Hz 047H3009 047H3018 24 V, 50/60 Hz 047H3053 047H3031 110 V, 50/60 Hz 047H3054 047H3032 220-230 V, 50/60 Hz 160-630 A 047H3055 047H3033 240 V, 50/60 Hz 047H3056 047H3034 TI 630 E 380-400 V, 50/60 Hz 047H3057 047H3035 415 V, 50/60 Hz 047H3058 047H3036 Conductor rail set 047H3027 for CI 85-105 Conductor rail set 047H3028 for CI 141-140 EI MN.90.K1.02 - VLT is a registered Danfoss trademark 7

The CI contactor When the contactor coil is connected to its rated voltage the mechanical system is activated and the electrical surfaces make contact. This produces the same phenomenon as when a ball hits a hard surface: it will hop or bounce. To protect the contactor lifetime and its contacts from welding, the bounce time must be as short as possible, at best under 3 ms. Fig. 1 shows that it is in this period that the charging of the capacitors, and the inrush current occur. Therefore the contactor is particularly vulnerable in this period. The CI contactor complies with the international standards for make current. Improvements to the contactor have brought the permitted make current right up to 15-20 x I N (I N is the motor's nominal load current). This ought to be sufficient, but some motors starting current can have a value of up to 15 x I N and the frequency converers starting current (inrush) can be more than 20 x I N. Furthermore, assuming a maximum of 20 worst-case switchings per day, 240 days a year for 10 years, the total number is over 50,000. In order to achieve a reasonably accurate test result three identical contactors were switched 50,000 times. Test results To help our customers, a table has been worked out showing the mentioned tests. As the capacitors in VLT types 3008-3022 are charged through large resistors which are then short-circuited, the starting current has a far lower value and they can therefore be dimensioned to AC-1 operating category (1 x I N, making and 1 x I N breaking - according to IEC 947-4 and EN 60947-4) in open and enclosed versions. The frequency converter starting current (inrush) The most significant benefits of relatively large capacitors in the intermediate circuit are that the inverter, which transforms the intermediate circuit constant d.c. voltage to a variable a.c. voltage, has an improved basis to generate a fully sinusoidal motor current with as high an effect as possible. Furthermore, the ripple current in the capacitors is reduced, thus also cutting down the power loss and selfheating. The lifetime of the capacitors and thereby the frequency converter are improved. Several measures have been taken to counter this high starting current. The solution most used is PTC resistors in the input circuit, which have a relatively high resistance on start. As the intermediate circuit is charged to a sudden level the PTC resistors are bypassed with a contactor. However, the PTC resistors in the VLT 5000 series are always short-circuited when the intermediate circuit capacitors are almost charged. Test criteria The CI contactors were tested in the labor-atory with 1 x 10 6 AC-3 operations (6 x I N making and 1 x I N breaking - according to IEC 947-4 and EN 60947). To resemble actual reality as closely as possible a reasonable number of "worst-case" switchings were added in order to stress the contactor as much as possible. To simulate worst case whenever the VLT frequency converter is switched, i.e. nominal input current each time, a fixed ohmic resistor is calculated and mounted in the variable resistor's place. Another criterion is that the intermediate circuit voltage must be less than 10% of its maximum value before the next cut-in. This goes much further than the real situation, since in practice the NTC resistor is not hot when the intermediate circuit is over 90% discharged. 8 MN.90.K1.02 VLT is a registered Danfoss trademark

Parallel switching of VLT frequency converters on CI contactors In certain applications parallel switching of several frequency converters connected to the same contactor can be required for both technical and financial reasons. Often this will give rise to problems since some frequency converters' relatively high starting current - also called inrush current - is not always taken into consideration. For some frequency converters the inrush current can be in the range of 15-20 times the nominal maximum input current I L,N. The inrush current occurs simultaneously with the contact bounce of the contactor and therefore the contact material is particularly vulnerable. Therefore it is very important to ensure an even, correct load of the contactor when several frequency converters are monted on the same contactor. Fig. 2 shows an application with five VLTs mounted on one contactor. Problems arise when the contactor is dimens-ioned to the total full load currents of the motor or the total nominal input currents I L,N, of the frequency converter and not to the sum of the contactors which would otherwise have been mount-ed before each of the frequency converters. The scenario shown in fig. 2, page 9 can serve as an example. If the contactor is mistakenly dimensioned according to the full load currents of the motor and the total current is distributed over the three contactor phases, the result is: I motor = 3.6 + 9.0 +2.2 + 2.9 = 21.3 A contactor. The following summated formula can be used for systems with both 1- and 3-phase frequency converters: CI VLT = CI VLT x number of phases 3 phases where: CI VLT is the contactor used for the system. CI VLT is the contactor which would be used if the frequency converter were mounted alone. number of phases is the actual number of phases for the individual frequency converter. 3 phases is the distribution of the 3-phase mains. Using the above formula to calculate the frequency converter input current I L,N the result is: I L,N = 7.1x3+13.3x3+5.3x1+10.6x1+8.5x1 =28.5A 3 so a CI 30 contactor is selected. With correct dimensioning, in other words according to the contactor for each frequency converter (Industrial Notes, lit.no. IN.42.TI.02), the final result is: CI VLT = 9x3+15x3+6x1+16x1+9.1 = 34.3A 3 which gives the right choice of a CI 37 contactor. The first two calculations show that the dimensions of the calculated and selected contactors are too small. At worst, this can lead to contact welds. It should also be remembered that if the load on a single phase exceeds that calculated nominal value (AC-3 value) of the contactor due to distorted distribution of the frequency converters, dimensioning should instead be to the maximum value of each phase. which means that a CI 25 contactor (25 A contactor) is selected. When dimensioning on the mains side of the frequency converter account should be taken of the distribution of the 1-phase types on the Fig. 2 MN.90.K1.02 - VLT is a registered Danfoss trademark 9

CI-CTI TM contactors and motor starters on the motor side of the VLT frequency converter When dimensioning contactors and thermal realys on the motor side of the VLT frequency converter, there are three primary factors to consider: The motor starting current The rated output current I VLT,N The frequency range in which the converter is to operate The discharge capacity in the screened cables, the output current harmonics and the position of contactor and thermal relay are secondary aspects. Primary considerations The VLT frequency converters are limited to the greates permitted output current. For most types, the factory-set current limit value corresponds to 160% of the rated output current I VLT,N. In practice this means that the maximum current to which the contactor may be exposed to is the rated current multiplied by 1.6 x 2 (fig. 3 shows the motor starting current on direct coupling with one contactor to the frequency converter output). Therefore the contactor starting current must be dimensioned to I VLT,N x 1.6 x 2 in relation to the AC-3 load category. The contactors can make a coupling current of at least 10 times the AC-3 current value of the contactors. A frequency converter can work in many different time intervals. If the frequency converter is e.g. working at around its rated frequency the contactor can be dimensioned directly to the frequency converter output current I VLT,N. At lower frequencies the output current period will be longer and, seen from the contactor on cutting out, the current more and more resembles a direct current, since it takes longer for the electric arc to be extinguished in connection with the sine curve's zero crossing. A relatively high voltage and current in connection with a low frequency means that the electric arc will also remain after the normal cut-out point of the contactor of 10-20 ms and will thus diminish the useful life of the contactor and at worst damage the contact disc itself. However, since the frequency converter's U/f ratio is reasonably constant, the voltage will be reduced at the same rate as the frequency and thus reduce the energy in the electric arc. On normal operation the contactors have an electrical lifetime of over 1 million make operations, but on DC-3 operation the lifetime is reduced in relation to the power the contactor is to break. DC-3 operation is the mode which most resembles the conditions of frequency converter operation at very low frequencies. The graph in fig. 4 can be used as a guideline to determine the contactor lifetime in relation to the frequency converter output frequency f M. Couplings Lifetime curve Frequency [Hz] Fig. 4 lifetime curve as a function of frequency Fig. 3 Motor output current 10 MN.90.K1.02 VLT is a registered Danfoss trademark

Secondary aspects For example on the output of VLT 5000 series a maximum of 150 m screened or 300 m unscreened cable may be mounted. The discharge capacitance will vary according to the type and size of the cable, but will normally be in the range of 120 pf to 220 pf per meter (see fig. 5). The longer the screened cable, the greater the cable impedance, thus increasing the effective current passing through the contactor. The scale of the discharge capacitances shows that this is of no great significance to a contactor or a thermal relay, since the contribution from the screened cable will lie within the normal current tolerance of the product. Fig. 5 shows the position of a contactor respectively close to the frequency converter and close to the motor. The figure also shows that the current load to the contactor is greater when it is mounted close to the frequency converter, since I 1 will always be greater than I 5 when a screened cable is used. A basic rule is to always dimension to the output current I VLT,N (also called I 1 fig. 5). The output current can also be read directly from the frequency converter display, which shows the mean current I RMS,MEAN of the three phases U, V, W. The discharge capacitance when using unscreened cable is not the same as for screend cable. However, the unscreened cable may have a discharge capacitance, depending on its installation and the environment in which the cable is mounted. As a basic rule, dimensioning should be to the largest current, i.e. the output current I VLT,N. Fig. 5 Outline diagram of installation with screend cables Parallel motor coupling The VLT frequency converters can operate several motors connected in parallel. In such systems the internal thermal proteciton cannot be used as protection of the individual motor, since the output current is programmed to the total motor current. Therefore thermal relays are necessary as individual motor protection (see fig. 6). The thermal relays can be used directly with a contactor for over-current protection of a motor and dimensioned to the rated current I N of the motor. The thermal relays comply with EN 60947-4 and can be loaded with up to 5% over-current before the motor cuts out. This provides room for any screened cable's discharge current and any current harmonics. MN.90.K1.02 - VLT is a registered Danfoss trademark CI-TI Contactors - VLT Frequency Converters EMC Fig. 6 Principle for installation with two motors When mounting contactors and thermal relays to the frequency converter motor side in connection with a screened motor cable, EMC directions must be followed in order to reduce the radiated noise. If the contactor and thermal relay are mounted at one place on the screened cable the screen must be connected in accordance with the current EMC rules in the VLT handbooks. Practical examples Example 1 A VLT 3032 frequency converter with a rated voltage of 3 x 400 V 50 Hz is mounted on a 22 kw motor. The nominal output current I VLT,N of the frequency converter is 44 A, and the frequency converter must operate in the range 20-50 Hz. The cable discharge capacity, the current harmonics and the position on the contactors and thermal relays can be disregarded. The contactor is first chosen according to the rated current, i.e. 44 A. In the "CI-TI TM Contactors and Motor Starters" catalogue it will be seen that a type CI 32 contactor can be loaded continuously at 63 A (I th (AC- and in open version). The inrush current is calculated at 44 x 1.6 x 2 ~ 100 A - which a type CI 32 can handle without problems (10 x 32 A). The lifetime of the contactor is estimated on the basis of fig. 4 at over 450,000 couplings, depending on how long the frequency converter operates at the various frequencies. Example 2 A VLT 5006 frequency converter with a rated voltage of 3 x 400 V 50 Hz is mounted with a 1.5 kw and a 3 kw motor with a rated current of respectively 3.5 A and 6.4 A (the sum of the two currents may not exceed the maximum rated output current I VLT,N ). Fig. 6 presents a general sketch. The cable discharge capacity, the current harmonics and the position of contactors and thermal relays can again be disregarded. The VLT operates at 10 Hz for 50% of the time and for the remainder at its rated frequency. Here dimensioning first takes account of the rated currents, so that two type CI 6 contactors and two type TI 16 thermal relays with a current range of respectively 2.7-4.2 A and 6.0-9.2 A must be used. The inrush current is calculated at 7.9 A and 14.5 A, which does not present any problems for the two CI 6 contactors, which can make at least 10 x 6 A. According to fig. 4 the lifetime of the contactor at 10 Hz is estimated to be 250,000 couplings, which for 1 million couplings at 50 Hz gives a total lifetime of 625,000 couplings. 11

12 MN.90.K1.02 VLT is a registered Danfoss trademark