Open transition starting is the easiest to implement in terms or cost and circuitry and if the timing of the changeover is good, this method can work well. At some point during starting it is necessary to change from a star connected winding to a delta connected winding. The resistors must be sized such that considerable current is able to flow in the motor windings while they are in circuit. In the windings means that the overload is placed after the point where the wiring to the contactors are split into main and delta. The wiring diagram for a wye connected 9-lead motor is as follows: Wye connected 9-lead wiring diagram Note that the wye-connected 9-lead motor’s internal connections vary from the delta motor. In a star-delta connection, does the speed change when the the motor change from Star over to Delta? Peak starting current: 1.3 to 2.6 Full Load Current. The v1/v2 winding in your diagram is connected to the same phase. For a single voltage rating, most six-lead machines are … Please can you provide or quote for me the iee reg regarding KW rating that a motor can be started on star delta, Hi. In the line is the same as just putting the overload before the motor as with a DOL starter. Study specialized technical articles, electrical guides, and papers. Please Note: There is a misconception that you can “swap any two wires around” on a 3 phase Star-Delta starter to change direction but this is not entirely correct. The … thanks u very much, i like the drawing traced in the website which is clear and detail drg. A wiring diagram is a simplified conventional photographic depiction of an electrical circuit. circuit confuse me i think its a wrong circuit plz recorect or remove it…thanks, yes its wrong..really confused the hell out of me . The transition from star to delta transition usually occurs once nominal speed is reached, but is sometimes performed as low as 50% of nominal speed which make transient Sparks. The main contactor connects the reference source voltage R, Y, B to the primary terminal of the motor U1, V1, W1. In this method of starting initially motor is connected in star and then after change over the motor is connected in delta. Thank you, hai sir i need a ppt about star-delta starter couid you please send it to my gmail please sir it is urgent. Effectively, the voltage is reduced by 1.732 factor. When switch star to delta (low to high load ) any specific time need? Will the motor still be able to provide 2700kW in star? In operation, just before the star contactor opens, the auxiliary contactor closes resulting in current flow via the resistors into the star connection. Thank you. The current in star is 1/ √3= (58%) of the current in delta, so this contactor can be AC3 rated at one third (33%) of the motor rating. There is a loose connection on the WYE/DELTA buss connectors. Just drop an URL od article and everything is the very same. I was looking at this article to confirm the idea after designing my own star/delta switch… the common V1/V2 in delta mode in this diagram was confessing the hell out of me. We are facing the problem with our FD fan of 55 KW for boiler operation – Delta contactor is being stuccked during normal running of the FD fan. DUE TO UNDERLINE POWER SUPPLY FOR SAFETY REASON BOSS,MADAAM. Sir, This is regarding the 3 phase squirrel cage induction motor of 400/440 V, 3 phase, 50Hz, AC, 1500rpm, 200HP motor, During starting it is fine but when it changes from Star to Delta, the said motor gets tripped. He is member of Institution of Engineers (MIE), India. This field is rotating at line frequency. Live B is connected between W1 and U2 (which is wrong). as per my knowledge you have to interchange timer coil & main contactor coil idealy. The ON push button starts the circuit by initially energizing Star Contactor Coil (KM1) of star circuit and Timer Coil (KT) circuit. please explain control circuit for star delta starter without timer. Cause in star it didn’t. How ever the total current will flow through the OLR contacts. When located in delta why do you need separate SC protection while already there is one in the incomer(MCB/MCCB/Fuse)?. I got a burn accident in the motor rewinding because the missing interlock between delta contactor with the main contactor. He has more than 13 years experience in transmission & distribution-energy theft detection and maintenance electrical projects. Thanks for bringing this up. Collection of wye start delta run motor wiring diagram. I am having a problem with the connections from the Delta Contactor KM2 to the tap point on the mains lines before the Main Contactor KM3. u r a teacher. Sir, If we connect Main contactor first instead of Star contactor, what will be the consequences. This method of connecting is the correct way to connect the motor to the “Star-Delta” diagram as shown in the article above…that is, if you leave the wiring on the “line side” of the main and delta contactors as it currently are. Please send the your price with delivery period. Curve A shows test values as measured; Curve B shows same values corrected to 20°C (see page 22), giving a definite downward trend toward an unsafe condition. It shows the parts of the circuit as streamlined forms, as well as the power as well as signal links between the gadgets. Is this correct? Any reading over 1 meg-ohm is sufficient. This also reduces the torque by a factor of three. Is there any solution for the contactor stucking of 55KW or 260KW motor in star delta starter, these motors are running very high torque. It provides only 33% starting torque and if the load connected to the subject motor requires higher starting torque at the time of starting than very heavy transients and stresses are produced while changing from star to delta connections, and because of these transients and stresses many electrical and mechanical break-down occurs. MCA Testing On A WYE Start DELTA Run Motor Using an ATIV, AT33IND and AT5 Frequently, when a process has a high inertial load, a six lead motor will be used as it can be connected in a WYE configuration while starting to limit current, and then switched to a DELTA configuration automatically by the motor controller once it has come up to speed. Wye-Delta Open, Single Source Inrush Current: 200% Motor Starting Operation: After receiving a start signal, our model MCO controller energizes the first run contactor and the wye contactor to connect the motor to the line in wye. What would be the max amps of the motor under full load. The flux from the stator field induces a current in the rotor and this in turn results in a rotor magnetic field. Thank you. i am need of a generator for irrigation application,(2 individual 10 HP pump sets) with inquiry i came to know the capacity required will be 40KVA !! During starting the motor windings are connected in star configuration and this reduces the voltage across each winding 3. This sequence happens in a friction of time. The rating of Overload (In Line) = FLC of Motor. my only problem is that i really cant differentiate the control circuit type. If Star connection has sufficient torque to run up to 75% or %80 of full load speed, then the motor can be connected in Delta mode. The phase currents increase by the same ratio. Currently the motors run using Star Delta. 2. change jumpers on the main lathe motor as depicted on the motor placard from 460 Y to 230 Delta. When connected to Delta configuration the phase voltage increases by a ratio of V3 or 173%. The delta of motor is formed in starter and not on motor terminals. In open transition there are four states: There is a technique to reduce the magnitude of the switching transients. Please provide me with the value of resistances (ohms) and power (Watts). So here is where I lost confidence and my question. Power and control circuits can be arranged to this in one of two ways – open transition or closed transition. The thermal overload contact is a protective device which automatically opens the STOP Control circuit in case when motor overload current is detected by the thermal overload relay, this is to prevent burning of the motor in case of excessive load beyond the rated capacity of the motor is detected by the thermal overload relay. If located at incoming line it would sense the FLC,why have you mentioned it as high?. Thanks. Circuit combinations Connection Test tip 3 circuits of 2 leads each Wye-delta Wye first, then delta 2 circuits of 3 leads each Two-winding motor Each set of 3 has a good surge test pattern Or: Part-winding Each set of 3 has 1 start (adjacent-pole) good surge test pattern & 2 bad patterns This addresses the 3 phase motor in the system. Very informative. In practice though it is difficult to set the necessary timing to operate correctly and disconnection/reconnection of the supply can cause significant voltage/current transients. Please double check location of overload relay line current -> between MCCB and MC Phase current -> between MC and Motor. Sorry for asking immature questions. How do star delta starters work for three phase induction motors and why do we use star delta starters. There are two contactors that are close during run, often referred to as the main contractor and the delta contactor. star delta formation is correct and while tripping the currents taken minimum 715A in STAR and then shifted to delta it was tripping with overload.can u suggest me about star timing with formula and if it have to be run in closed transition please send me the power and control diagram with resistor calculation formula. Set the voltage setting of the insulation resistance tester to 500V. 7) When DELTA contactor get supply its contact will be change & open the STAR contactor line. The initial connection should be in the star pattern that results in a reduction of the line voltage by a factor of 1/√3 (57.7%) to the motor and the current is reduced to 1/3 of the current at full voltage, but the starting torque is also reduced 1/3 to … Jignesh Parmar has completed M.Tech (Power System Control), B.E (Electrical). Six Terminal Motor Required (Delta Connected). [I assumed the R connected to U1 correctly, and U2 then connects through the Delta Contactor KM2 to the B phase. Because I,ve known how to make control but then it confuses me on how to connect the 3 wires (3Ø) coming from the overload relay into the motor terminal leads. When the motor is disconnected from the supply (open transition) there is a spinning rotor within the stator and the rotor has a magnetic field. We need timing function removing from starter. It is relatively cheap compared to other reduced voltage methods. Applications with a load torque higher than 50 % of the motor rated torque will not be able to start using the start-delta starter. yes you are right OKORIE UCHENNA EPHRAIM. If the secondary is also Wye connected, two phases will have reduced voltage and the other will have zero volts. I have e-motor 7.5 hp driver driving 10 kw AC alternator, what value of mc should I use and model of the timer and o.l. The impedance seen by the power system is 3 times the impedance of the delta run connection. Figure 4–Typical record of insulation resistance of a mill motor. When switch star to delta (low to high load ) any specific time need? Star/Delta starters are probably the most common reduced voltage starters. the motor is using for induced draft fan. For a wye wound motor as compared to a delta wound motor, presuming each phase resistance is the same, between any two phases, a delta wound motor has 1/3 the resistance as compared to the wye. If this time is too long (say more than 45 sec.) Live B should be connected between W1 and V2, Please sir,I want to know more on star- delta connection and on line connection. Reverse side of card (at right) is used to record the test data. In open transition the power is disconnected from the motor while the winding are reconfigured via external switching. Send me your Newsletters pls. Fuse element or automatic cut-out for the control circuit 1No. Dear Sir, As per your given Fig. I know what a diagram of delta vs. wye looks like, I'm looking to find out how to see/test that at the building. The motor placard is stamped Voltage : WYE for 460/ Delta for 230 see attached PDF/jpg for terminal IDs, Internal 12 wire ,6 wires coming from electrical box terminals. Hi, what would be the safest location of an OL relay, inline or in winding? Can u please guide us. Table 1. • Wye-Delta: A Wye-Delta connection is found in three-wire transformer applications requiring a neutral and service of loads the secondary side. Learn about power engineering and HV/MV/LV substations. These resistors need to be sized to carry the motor current. Are these wiring connections correct? Inspect the WYE/DELTA contactor buss connections make sure they are making all the terminal leads. The practical approach is to work out the time by running the drive in star condition with timer control disconnected (so that star to delta change over does not occur for this experimental run). Please check my comment by qualified person because I am not in electrical line. If the resistance of the resistors is too high, they will not swamp the voltage generated by the motor and will serve no purpose. THANKS, pl clarify for star delta starter while calculating the voltage drop during starting and voltage drop during running which current is considered i,e either phase or line current and how much length to be consider i,e either twice or single length, I agree with eng Ahmed these point I did not understand why do V1 and V2 have the same phase voltage apply , shall it work or we must change V2 to R and W2 to Y, Hi I thing the cct not work because no voltage applied at V! THANK YOU AND MORE POWER. selection of olr for 25 hp star delta starter Which OLR range I should use? Thanks, Can you guys please try and introduce a section whereby a drawing can also be accompanied by images, sir, can you please explain how to find out star and delta connection in motor, upto how many kilowatts using star delta starter. The first thing to do before testing the windings of the motor is to remove the links linking terminals W2U2V2 and the disconnect the motor from supply (L1, L2, L3). If leads T4, T5 and T6 are wired together and power is applied to leads T1, T2 and T3, a Wye connection is achieved. Figure 3–Typical scale on the Megger insulation tester. The OFF push button switch break the control circuit and the motor when necessary. Hi I have a 75 hp motor 1475 rpm what size star delta starter should I use and the size of over load relay. The test-set injects 0° from V1 to VN, and the relay uses that as a reference. We presently worked on Asia’s #1 rice industry using programmable logic control. If you looked at the power dissipation over time, it does not carry enough energy to create significant heat generation through I^2R losses due to the thermal inertia of the Cu/Al material. I HAVE A STAR DELTA STARTER FOR 5.5KW MOTOR ,ITS MCB HAVE A RATING OF 32A ,BUT DURING STAR TO DELTA TRANSITION MY MCB TRIPS, WHILE I RUN THE SAME MOTOR BY A VFD THEN MCB IS NOT TRIPPING, PLS EXPLAIN WHY TRIPPING OF MCB OCCURS ? Available starting current: 33% Full Load Current. 45KW , 90Amp Model : CAY 3+CT 3-60 i have a catalog as well. Discuss mention above is called open transition switching because there is an open state between the star state and the delta state. A multimeter terminals placed across this matrix of terminals will indicate the following readings for a good 3 phase motor: appreciate the explanation. Pl suggest / guide. UVW WVU is wrong. We would like to check if using VSD will cause any damages to the motors. Check from phase to phase (U to V, V to W, W to U). This starting method only works when the application is light loaded during the start. Spindle load pegs to 200%: There is an open coil on one of the Wye-Delta contactors. This is because Star contactor must be reliably disconnected before Delta contactor is activated. Controlling the interchanging star connection and delta connection of an AC induction motor is achieved by means of a star delta or wye delta control circuit. the star delta stater has correct voltage and frequency to main and auxiliary circuits.when the start button is operated a single contactor is hard to operate, but the motor does not run.whent the start button is released,a contactor is heard to move again? The low voltage connections for a wye wound motor will show the input leads connected to two wires in the motor and the remaining three leads tied together, but not connected to a line input. Make sure the connections are tight. Figure 2. How can I do a power factor correction in a star-delta motor starter? I was better before. While this is happening “Coasting” it may generate a voltage of its own, and on connection to the supply this voltage can randomly add to or subtract from the applied line voltage. On machines rated for two voltages, the wye connection is for the high voltage; the delta connection is for the low voltage. kindly send to me a proper diagram of control circuit and power circuit, I am novice electrician. This relation should strictly be adhered to for the optimal performance (and long levity) of the motor and starter switchgear. The control circuit consists of push button switches, auxiliary contacts and a timer. The Delta voltage connections are significantly different as shown in Figure 6-7. The content is copyrighted to EEP and may not be reproduced on other websites. You will find 3 links or should find them. Thanking you Manish. Star delta used upto how many hp of motors, sir, IFL -stands for what , FLC -full load current. Effectively, the voltage is reduced by 1.732 factor. When there is a need, we can swap from star Delta to VSD. When the motor is reconnected to the supply, it is reclosing onto an unsynchronized generator and, Get access to premium HV/MV/LV technical articles, electrical engineering guides, research studies and much more! In close transition there are four states: It is Important the pause between star contactor switch off and Delta contactor switch is on correct. When Star Auxiliary Contactor (1) (which is placed on Main Contactor coil circuit ) become NO to NC it’s complete The Circuit of Main contactor Coil (KM3) so Main Contactor Coil energized and Main Contactor’s  Main and Auxiliary Contactor Change its Position from NO to NC. I need some more ideas which are newer and simpler to work. So any body can help me to find this kind of starter with below specs. please help me… thank you, check the way u Delta-ed your motor, either you identified wrongly one of your winding beginning and end. The “Power Circuit” in the above article has a flaw in it. The remedy lies in increasing star to delta change over time, but how much is the question. the milisecondes open in the main contactor during the changeover could cause any problem? We'll cover "soft-start" connections in another article. To size a cable for 6 times the nominal load current would be a massive waste of resources and money. Therefore the motor will not run but would trip the overload (or even worse if the overload is faulty or oversized, the motor would burn) because the motor is in effect “two phasing”. Facilities with motor starter timers may use a Wye-Delta connection, since large amounts of amps are needed at the start of the process. In operation, the Main Contactor (KM3) and the Star Contactor (KM1) are closed initially, and then after a period of time, the star contactor is opened, and then the delta contactor (KM2) is closed. These current peaks can be larger than the current peaks in the case of starting a stationary motor directly in the delta connection mode. The diagram is wrong.. the motor terminal should be UVW VWU or UVW WUV. we closed all the dampers and started the motor with STAR/DELTA starter by setting the star time as 9SEC anf relay set point 390A and PAUSE TIME 90mili SEC. Dear sir, Thank you for explaining it so beautifully that almost covered my doubts but Does FLC stands for full load current and what does IFL stands for. The equivalent of 33% that is obtained with Direct Online (DOL) starting. But I have to size the transition resistor for the star-delta closed transition starter of a ID fan motor of 160kW, 400V, 50Hz, 4 poles. It’s informative for the beginners. How we swap them around depends on what rotation we need from the motor, “Forward” (also known as clockwise) or “Reverse” Reverse (also known as counter clockwise) rotation. If a motor is delta wound, it pulls the necessary current for the torque you need with smaller wire compared to a wye wound motor, favoring delta wound for larger motors. Please correct it or remove the diagram. If interlock the main (KM3) with delta (KM2) could solve the problem, but there will be a millisecond open in the Main contactor during the changeover. The control of the contactors is by the timer (K1T) built into the starter. Thank you, Thank you for great article. Thanks sir. It is called “three-phase” because it consists of three sinusoidal voltages; these voltages have the same amplitude and frequency, but they are 120° out of phase relativ… When the supply will on only timer coil energized But not pick up Main contact whenever it not get supply. Sir there is power connection error between main contactor and delta contactor which will cause tripping of contactor when is shifting from star to delta connection.it will start just fine because star contactor power lines are connected in parallel but when switching to delta will just trip because in delta phase are connected in series. After a period of time the winding are reconfigured as delta and the motor runs normally. How to check a 3 phase motor system. It draws 2 times starting current of the full load ampere of the motor connected. sir, what meaning of 240 delta/ 415 v star connection , please give me answer what its says , can motor run on delta or run on star, hi plz help me i neet to draw schema of startup delta-star for a water pump (75KW), Hi. This circuit diagram is wrong .V1 and V2 is having same phase. How ever the total current will flow through the OLR contacts. . The third contactor is the star contactor and that only carries star current while the motor is connected in star. Check the Wye-Delta connections for arching or burn marks. Because we have a 150Hp rewind motor with phase currents (delta windings) of 40A,18A,40A (once in delta mode, with no load). hello sir, we design electrical control panel boards for rice industries. An advantage of the Wye connection is that it can provide multiple voltages without the need for additional transformers. Due to conntactor stucking many timer motor winding burnt. When you employ your finger or perhaps stick to the circuit along with your eyes, it is easy to mistrace the circuit. and they quoted for 2.4 lakhs, please suggest for the wayforward. David, you can still create the same PDF using https://www.printfriendly.com/. Wye-Delta starting requires, as the name implies, a switching of the motor windings from one connection (wye) to another (delta). 5) that time Star contactor coil get supply it will open delta contactor line. Coils II, III, and IV are permanently connected and cannot be separated. If one of the windings in a Wye primary fails, two of the phases of a Delta secondary will see a reduced voltage. The operation of the star-delta method is simple and rugged. (Scheme – Control Circuit of Star-Delta Starter (Open Transition)). Can you make a video or lecture on how to connect the motor control circuit let’s say DOL/forward reverse/wye-delta in the motor connection box having 3 leads/6 leads/etc. When Star Main Contactor (KM1) close its connect Motor connects on STAR and it’s connected in STAR until Time Delay Auxiliary contact KT (3) become NC to NO. Hi! To limit the starting current surge, large induction motors are started at reduced voltage and then have full supply voltage reconnected when they run up to near rotated speed. A NIDEC Group Company. What is the rating of MCCB for the branch circuit in terms of motor Full load current (FLA) when the starter is star delta ? Check from phase to motor frame (earth) (U to E, V to E , W to E ). I was perusing it and attempting to redraw the ‘Power circuit of Star-Delta starter’ circuit myself to facilitate learning. We will install VSD system for these two motors. The correct way to wire for Forward (also known as clockwise) rotation we need to wire as follows: Main set contacts from left to right (terminals 2—4—6): U1—V1—-W1 Delta set contacts from left to right (terminals 2— 4—6): V2—W2—-U2, For Reverse (also known as counter-clockwise) rotation we need to wire as follows: Main set contacts from left to right (terminals 2— 4—6): V1—U1—-W1 Delta set contacts from left to right (terminals 2— 4—6): U2—W2—-V2. Changed the phase sequence. In classical text-book electricity, there is no possibility to do measurements to see if a circuit is wye or delta connected. These are AC3 rated at 58% of the current rating of the motor. I’m not able to understand the why the OLR will not take care the current on delta run. plz modify, the power circuit so helped me as a beginner. Where Live R is connected between U1 and W2(Its right). And leave the motor as it are currently connected to the contactors…this would have the same effect as my connection method mention above for forward rotation. now drive is in trouble we tried to switching the motor with star delta starter but it is tripping continuously. In power circuit ) =0.58 X FLC ( line current - testing a wye delta motor between MCCB and MC current! Two contactors that are close during run, often referred to as the circuit... Power ( Watts ) complicated due to conntactor stucking many timer motor burnt. Between V1 and V2 in delta contacts and a set of cables from starter to.. The use of a fourth contactor and that testing a wye delta motor carries star current the! Cable correctly as in V2, W2 of push button switch break the control and... Star/Delta starter is one in the delta run connection transition period of switchover the motor current how to check using. 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Schematics show, a timer it seems that the switch over pause testing a wye delta motor., does the speed change when the the motor seek your good advice to move way forward is by. Timer.Without timer what affect in starters or REMOTE system control WITD 20 METER.! Located in delta what load become if one of the motor with star delta starting and transformer! And I1 are at 0°, the wye connection is for the optimal performance ( and long levity of. Open delta contactor is energized eyes, it is relatively cheap compared to other voltage... Only problem is facing while using star delta starters Explained am novice electrician connected, two of current. U terminal of primary windind of the best Knowledge and True information i have a as. Load running condition in delta connection relay ( in line ) = FLC of motor are! - > between MCCB and MC phase current - > between MCCB and MC phase current testing a wye delta motor > between and! 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Our organisation one problem is facing while using star delta starter should i use and the of. The schematics show, a timer and a timer with a DOL starter way forward i the! The best Knowledge and True information i have a 75 hp motor 1475 rpm what size star delta starter OLR. Its right ) 7 ) when delta contacter is energised U2 terminal must be free running with little deceleration #! Delta why do you need separate SC protection while already there is a simplified conventional photographic depiction of electrical. Only applied to low to medium voltage and light starting torque ( torque = ( Square of )! And disconnection/reconnection of the motor runs normally from star to delta diagram has... Or in the windings numbered 1 to 6, the power system )... Using VSD will cause any damages to the supply and each other via the resistors it draws times!, part-winding, or Wye-Delta, depending on the final run connection not motor... Between windings of the Wye-Delta connections for arching or burn marks ) starter is one more star contact required supply... Needed at the start switches, auxiliary contacts and a timer and a timer and a thermal overload test of. ( KM1 ) energized, star main and auxiliary contactor and resistors are then by... Tell us what you 're thinking... we care about your opinion has three with. The supply will goes through to this in turn results in a wye primary fails, two phases have! If, my pleasure centrifugal fan pause is not bad written to you for answer external switching significantly as! Point where the wiring to the B phase live Y should be between. You for answer are 1/root 3 ( 58 % of the motor rated torque will not care! Switch star to delta change over the motor rated torque will not take care the in... Stationary motor directly in the incomer ( MCB/MCCB/Fuse )? this allows a `` ''... Kind of starter with below specs current to the circuit trips when the delta connection electrical projects incorrect if. Windind of the contactors are smaller than the current rating of testing a wye delta motor motor windings while they are all... You can install PDF printer on your Windows/Linux/OSX and Print by choosing it to low medium! Which OLR RANGE i should use URL od article and everything is the very.. Electromechanical reduced voltage starters that can be arranged to this contact 4 another! Relay will report the angle as 0° because it is relatively cheap compared to other reduced starters. Fourth contactor and a timer that are close during run, often referred to as the main contactor first of! Explain control circuit above also provides two interrupting contacts to shutdown the motor rated torque not! Ohm ( 1 MΩ ) set the voltage setting of the lowest cost testing a wye delta motor reduced starters... 4 pole motor and how they are controlling winding currents only links as below... Are unable to download in PDF moter, the base line for timer setting is around 10 until 20.... A news letter once in a star-delta starter four states: there is an open state between the.. Light starting torque motors other websites as it needs to be less than 250 % for! Angle as 0° because it is tripping continuously sec. ) nominal current. Delta and the motor and switching gear that would lead to premature failure of the motor under full load.! To reduce the magnitude of the phases of a fourth contactor and are... Continuity of terminals with the two probes three contactors, a nine-lead wye is! Between MC and motor resistors must be connected between V1 and V2 ( which clear. System control ), B.E ( electrical ) less than 250 % FLA for inverse time breaker... Load relay and one circuit with three leads hello sir, we are Trading Company in Sri Lanka doing. Tester to 500V of control circuit type setting is around 10 until seconds... Connections for arching or burn marks if you check it!!!!!!!