Star delta motor connection

For star delta stater,the motor connection must have 6 cables from control panel and 6 terminals at induction motor ( U1,U2,V1,V2,W1,W3).To wiring the motor connection for star delta starter,the important thing that we must fully understand is about the basic of STAR DELTA MAGIC TRIANGLE.

For detail about star delta stater please read my last post about it. From this triangle diagram,we can determine the correct phase,cable termination for right terminal and the rotation.As we know,the star delta stater is so tricky if we not fully understand the concept and their method. This time i want share my technique when perform wiring task and connected to the star delta stater for induction motor.

Don`t worry,it simple and easy if we understand the basic concepts.I explains detail step by step how to do it :D


What is Star Delta connection?

Star delta magic triangle

When we refer to this diagram,We can see correct terminal for the winding for each phase : *CAUTION: Please refer to the name plate of motor to confirm the winding numbering ( U1,U2,V1,V2,W1,W2 ) and the motor connection of winding.

Why it very important??Because each manufacturing have their own style for numbering and winding motor connection.

Star Delta phase and terminals

RED PHASE : U1 and W2 YELLOW PHASE : U2 and V1 BLUE PHASE : V2 and W1 So..from this formula,we must wiring the motor follow the phase color code.

See my example below :-

We can refer the complete wiring for star delta starter diagram below.If you want change their rotation for clock-wise or anti clock-wise,you need change two of phase ( RED or BLUE) at delta contactor.I share the technique how to change rotation in my next post.

If you want motor rotation for clock-wise,the phase colors are RED,YELLOW,BLUE.But if you want anti clock-wise rotation,the phase colors are BLUE,YELLOW,RED.For star delta control wiring diagram,please refer to my post about star delta diagram control




  1. BHARGAV says


  2. Please give the curve showing the current surge (current vs time) during change-over fro star to delta as well as the current vs time curve if the same motor is started in direct on line method, in the same graph sheet. Also please give korndorfer type connection(with transition resistors)-for no break to avoid current surge.

  3. Venkatesh says

    Hello sir ,
    I’m having a small dounbt , in terms of converting a star winded motor to a delta winded .. motor was labelled as star rated in the motor name plate. so pls tel me is it possible to change the star winded to a delta winded ??

    • If you want run the motor using star delta starter,u must take off all cooper bar at terminal of electric no connection of star or delta.
      MAKE SURE : The motor design is DELTA connection only for star delta starter.if you used motor design STAR connection,your winding will burn out :D

    • Presley Chilumbu says

      If you motor control is DOL, bring out the 6 leads out of the motor and if already paired they will be labeled T1U1, T2V1, T3W1, T4U2, T5V2, T6W2. Depending on your desired motor rotation connect R(T1U1,T6W2), Y(T2V1,T4U2) and B(T3W1,T5V2). Your motor will be connected in Delta.

  4. sir ,i dnt get my ans of qus yet
    my problem is that whn motor comes to delta contactor the motor stops wht cn be the reasons behind this

    • mukul,please check your power supply wiring for motor terminal.make sure ur 3 phase wiring from delta contactor to motor is correct.

      • fayyaz says

        see reason to stop motor in revers direction in delta connection is the one winding is getting connected in same phase.

      • sreeraj says

        check the star delta contactor and main contactor connection and motor connection and power supply also

    • shriram says

      for my experience, cont-actor is not working

  5. Please give the time setting of changeover delay from star to delta. Does it depend on kW or speed or LRC of motor?.

    • Time setting for change over is so subjective,it depend on load and inertia.Theoretically star change to delta when it reach 80% of full speed.from my experience,i setting around 10 sec to 15 sec maximum.

  6. zonaid hasan says

    i have a 20hp motor(20*746 watt=14920 watt).it requires a star delta control system.what should be the three MC ‘s two MC’s will switch operation,their ratings will be different?plz help me out with this MC’s ratings for this 20hp

    • First, you must know the Full Load ampere for your motor.
      FLA = 14920/(415*1.732*0.9)
      FLA = 23 Ampere

      So for MAIN contactor
      = FLA / FLI
      = 23 ampere

      For DELTA contactor
      = FLA x 0.58
      = 23 x 0.58
      = 13.4 @ 15 ampere

      For STAR contactor
      = FLA x 0.33
      = 23 x 0.33
      = 7.6 @ 8 ampere

      Please used AC 3 rating for contactor..please refer my last post about magnetic contactor sizing

      NEMA CODE :
      430.22 (C) Wye-Start, Delta-Run Motor. For a wye-start, delta-run connected motor, the selection of branch-circuit conductors on the line side of the controller shall be based on the motor full-load current. The selection of conductors between the controller and the motor shall be based on 58 percent of the motor full-load current.

      why multiply with 0.58?

      The Star/Delta starter is manufactured from three contactors, a timer and a thermal overload. The contactors are smaller than the single contactor used in a Direct On Line starter as they are controlling winding currents only. The currents through the winding are 1/root 3 (58%) of the current in the line.
      There are two contactors that are close during run, often referred to as the main contactor and the delta contactor. These are AC3 rated at 58% of the current rating of the motor. The third contactor is the star contactor and that only carries star current while the motor is connected in star. The current in star is one third of the current in delta, so this contactor can be AC3 rated at one third of the motor rating.

    • salim uddin says


  7. manoj bhangale says

    Please give me control circuit dia. with explanation of star-dalta starter.

  8. B.Srinivasa Raju says

    I want star delta connection from starter in side terminal to motor terminal box with colour code

    • I already explain in my just follow the wiring diagram for power circuit with color code..

      • santosh dhadke says

        Can u explain me about 7.11 Hp motor how much taken no load current ? But this motor is rewinding motor .

  9. sir we want the diagram


  11. IRSHAD AHAMED says


    i have a problem for start delta moters pls wright a good solition.
    probleam as
    when moter changed star to delta pocition it s gosse to trip main braker
    i checked panel first with out moter star delta condecter working good but when i connect moter terminal it s triped main
    when its run star it is ok its happen delta condector catiching time only
    so pls ans me what can i do the next step
    i checked moter wiring with megeer ther no rong simtems
    so pls wright good solition

    • Anil Paul Jacob says

      you have a problem in power wiring either in panel or in field wiring …. or check the contactors for the damaged contacts

  12. how rating motor connet in star delta

  13. Sadoon says

    Dear Sir,

    really appreciate your efforts explaining in details. I just have small comment on the picture above (wiring connection), you may notice that there should be V2 instead of U2 of the blue wire coming from the delta contactor.

    Thank you

  14. Sadoon says

    Dear Sir,

    can we have the same explanation on Auto-trans starter used in motor.

    thank you

  15. Thanks, very helpful

  16. Dear Sir;

    I saw ur web side it’s very awesome and grate, the way u explains is awesome and to point also. I love ur way. Dear sir I join mine life first job as electrical tech. I am new in plant. I am working at wharf area. My boss told me to make a presentation on Star and Delta, I need to know what I tell him in this topic, he says I need mathematical equations also and explanation and trouble shooting, what problem it can comes, how to tell without name plate, is it delta or star connection? in any motor. We are normally using 400v and 3 phase motors at every place. Need ur guidance to make best presentation.

    Will be looking forward for ur kind reply.

    Tc sir
    God bless u


  17. i would like to ask regarding the current above the two contactors namely main and delta when running operation.somebody told me that the above of these contactors have the same current.and the current under these contactors is less than the above.He is trying to say that the above current are the line to line currents while under the contactors are per phase currents.We are arguing the size of the conductors above of these two contactors, namely the main and delta contactors. I beleive that the above of these contactors are still in the per phase condition. The point were the two line 1 e.g. line 1 of main and line 1 of delta connected or joint,this is were the line to line condition.
    I hope you will give me clarifiacatioin regarding this matter.
    thank you

  18. Godswill Onwusoroaka says

    i connected a 110kw of motor to star-delta but the speed is seem to be slow, what is the problem

  19. Najesh says

    can we replace contactors with triac… can you give ckt dia on that……

  20. Dancan says

    i took my stardelta motor for rewinding,when it came back the terminals were not labelled.Please help me to identify the U1 V1 W1 AND W2 U2 V2 using multimeter.

    • Dear Dancan,
      Use your multimeter and select continuity to checked pair or motor terminal.If buzzer beep that mean it the pair for the winding connection.

      U1 = U2
      V1 = V2
      W1 = W2

      i hope it answer your question….

  21. send me the formula of selecting the conductor size for wiring

  22. please send me the formula to selecting the conductor size to wiring

  23. please help me identify w/ch type of 3phase motor should i use the star-delta contol.i’ve seen motors having 220/440/3ph and 660/440/3ph.both are Y/D.which one is for Y-delta starter,or both of them are applicable,or not for such control wiring? thank you and hoping for further knowledge regarding this matter.

  24. I like to Automation from you

  25. I have a problem when i connect to star-delta connection.
    The motor is 7.5kw.
    When i connect into star-delta, it run well in abt 8A, everything seem OK but when i leave it for one day (the motor is running with 24hr timer with 4hr run and 4 hr rest cont.), the contactor burned. I already check all wiring mega OK, component OK, my contactor with 12A i even change to 20A (incl MC, Star & Delta contactor) but it still burned. the change over relay is working well also, i set it abt 5-10 sec for change over.
    I feed up and change it to run in DOL, it work properly and have no problem with the same 24hr timer although earlier i suspect the 24hr timer problem make it start-stop too many time.
    I doubt is it the motor problem (let said if coil less or something related to star/delta running not enough speed when change over) will cause this matter which is abnormal for me.
    However, there are 3 set of motor with same size that i have the same problem with it.

    Anyone can help to answer me?

  26. jackie says

    dear sir,
    surley it is possible to swap 2 phases over on motor connection box?
    instead of delta contactor

  27. jackie says

    ^ for reversing direction of motor

  28. the phase shifting from main to delta contactor should take place,while changing star to delta.

    if anybody can clear this ,please reply

  29. Hello you have mentioned the wrong numbering, kindly correct the same.

  30. fayyaz says

    what connection shown for motor for starter is ok but to change direction just changingtwo clourof delta contactor will notwork i ids agree with you.just go throw the circuit.

  31. fayyaz says

    just see due to this one winding gets connected in same phase i mean for ex. w1 is connected to red
    w2 is alsoget conectedto red.

  32. dinesh kumar says

    hi i have i submersible motor,for that we r using DOL wats d problem is as d motor is immersed in the borewell we cannot hear d sound,so sometimes we forget to turn off d motor,so i hav planned to connect a buzzer with d starter,so whenever i turns on d motor i should hear some sound.

  33. hello sir,
    i want difference between relay and contactor?

    • Hello..
      roughly description :-
      Relay : Normally in small size and for small application.Common used for control circuit or application.power supply range : 12 DC – 240 VAC

      Contactor :Have several type and size.Normally use for power control such as motor starter and power supply distribution for internal used.Rating size for contactor depend on kW or Full load ampere.

  34. iam greatly informed on your elaboration on electrical issues. pls sir can give me a detail explanation on how to wire a three phase capacitors to a three phase motor star delta starter panel

  35. I like the way you elaborate on electrical issues. Please,can you tell me how to connect three phase capacitors to a 30KW three phase motor in the star delta starter control panel

  36. Anil Paul Jacob says

    Fakansa, There are capacitor banks which can be used on electrical networks with induction loads (motors). in this, APFCR (auto power factor correction relay will take care of capacitor selection = number of capacitors required for power factor correction will be selected by APFCR by its own. In your case you need to connect only one capacitor to the 30 KW motor. You can connect the capacitor through a contactor with required ampere capacity. and this contactor can be switched on manually after starting of motor. in another option you can control the contactor for the capacitor through a timer (making on delay after the motor running in full speed) to avoid the surge current.

    • HI Anil,
      Thanks for your answer…it detail and easy to understand…i`m very appreciate with your input and shared some knowledge..

  37. alexander says

    Sir, How we will size the cable if we are using double supply cable for wye-delta pump motor

  38. Anil, thank you so much for your information,Iam glad

  39. AK Majumdar says

    I have two motors each capacity 110KW 440V pf.75. Two motors simultaneously drive a fly wheel through pulley. Weight of Fly wheel is approx. 16T and dia. 3Meter. These motors have Star/ delta connection. Both motors start together. What should be the star to delta time set.

    • Hi AK Majumdar,
      This is a popular question for star delta starter.Ok from my experience,to setting the timer from star to delta,we cannot get the perfect time but we can used 2 types of measurement to get approximate time (second ).

      1. Use the clamp on meter ( analogue ) : Get information for motor Full Load Ampere(FLA),measure the ampere during star and set stop watch.Stop the watch and see the time when ampere reach 80 % of motor FLA.Use the time to setting your timer.

      2) Use the RPM meter : Get information for motor RPM speed.Use the RPM meter to measure motor RPM and use the stop watch to get a how many second that motor achieve 80% of RPM during star.Use that time to setting your timer.

      Typical times for Star Delta starter timer is around 10 until 25 seconds…but its depend on load.I hope this technique can answer your question.Please read my post about How to set timer for change over of star delta starter

  40. Siva balan says

    Dear sir,

    I would like to know how to terminate the star-delta motor. We are using Crompton Greaves(110KW) motor. Kindly help me by giving the detailed termination detail’s for the star delta motor.

    Thank you

    • Hi Siva,
      I already explain how to connect power supply for star delta motor..please refer the wiring diagram at the bottom post.

      Red Phase from Main contactor : terminal U1
      Red Phase from Delta contactor : Terminal W2
      Yellow Phase from Main contactor : Terminal V1
      Yellow phase from Delta contactor : Terminal U2
      Blue Phase from Main contactor : Terminal W1
      Blue Phase from Delta contactor : terminal V2

  41. Hi sir
    I just want to know that is there any problem if a 3 phase motor connected only with star connection( I heard that the star connection only for starting the motor ) So please confirm .

    • Hi Habeeb,
      You can use DOL or VFD starter if connected motor for star or delta connection.But make sure your motor voltage is suitable with star or delta connection.please refer to your motor name plate.

  42. mahesh deshmukh says

    Hi sir,
    I want to know that why we interchange the two phase in star delta starter?what is the purpose of that?

  43. sumith mohan says

    i have a issue with star delta starter.

    my delta is starting first then switches to star after the relay timer

    what may be the problem?

    i have checked the control schematic, and it is proper.

  44. Mr.Gururaj Deshpande. says

    I am basically an electrical engineer working in Pharma company in India.
    I am stuck-up in designing power supply alternative to already installed maintenance-. free Battery.
    A deep freezer running on normal Single Phase power supply has Operator’s panel & display where the temperature is displayed & temp & alarm setting can be modified.
    Naturally when this power fails (even for short duration) of ONE minute, this equipment shuts down.
    During this period, in order to the DISPLAY to show actual temp. DISPLAY is powered by a battery.
    Rating of Battery is: 8Volts, 7 AH.
    Now I want to replace this Battery with a A.C power Supply & provide UPS Power to this NEW power supply to ELIMINATE the battery.
    How to decide about the current capacity of this power supply?

  45. simret says

    hi, i want to ask how to know circuit breaker size current calculator for 3 phase ,380 volt ,20hp delta connection motor

  46. Aditya Sarma says

    helo sir how to calculate the capacitor and relay for an three phase submersible motor for example i need to install a capacitor for 110 hp motor how can i choose the right one

  47. I wants you to help me on how i can determine over-load setting for three phase ac motor star/delta,three phase DOL starter & single phase motor connected to 380 volts,50 volts.

  48. yikunoamlake haile says

    hi my name is yikunoamlake haile.I live in Ethiopia and I am so interested by your work I need to learn about industrial electricity so I am electrician so please support me as you or the company need.

  49. khukon says

    Haw do concreter push button convection

  50. gourav says

    Motor winding

  51. Penuel says

    I have a problem with my circuit, on star am getting a low amp reading. and on delta its high and the motor is over-heating. i have checked my connections, winding’s and followed the u1w2/v1u2/w1v2 connection. i have wired thousands of circuit but this one is giving a challenge. suggestions are welcome

  52. dear sir,
    plz suggest me control wiring diagram for contactor coil voltage 110v ac…I need to start &stop 30hp motor by start delta logic….Is it neccessity of step down transformer??? plz help me

  53. how to choose star,delta and main contacter for 20 hp motor

  54. b k malviya says

    I have to provide a power capacitor to a 30 HP motor having star delta operation and the three contactors for it. I do not have a automatic power factor correction panel. As such, I have to connect a capacitor to the contactor. To which contactor viz main, delta or star contactor should the capacitor be connected.

  55. Please provide theory of current taken by 3 phase induction motor in star & delta connection.

  56. Kalpesh says

    Respected sir,
    i am having a 15 hp motor which runs with vfd during auto mode and runs by star delta during manual mode, sir the motor runs okay in manual mode but during its auto mode the body gets phased and voltage across the terminals is that of the single phase one so please convey me with the problem and the solution.

  57. Kanakaiahnerella says

    How to contecat star delta motor

  58. p santhosh says

    how to do synchronising in plants

  59. I have a 440 3 phase 1.5h.p.motor on lathe. On plate, it only states 440. Can this motor be altered to run with a single phase to 240v 3 phase inverter?

  60. Ghulam Hussain says

    Dear sir .i have a single phase motor. which takes 15 amp on full load. so i have installed many diffrent contactor with diffrent amp. withins few days contactor is going to out of order. can any one help to to solve this problem ?
    Looking ahead for your kind reply….

    • Hi Please check your contactor ampere rating.Make sure it higher than your full load ampere.

    • rathnam chargeman 33 kv says

      you never state the motor hp
      1 check you pulley
      2 check you bearing
      3 check you contactor 3pole or 2pole
      4 simple test di connected the pulley and test free load

  61. Rajaptel Biradar says

    Dear Sir,

    I need some helps how can i change direction of rotation of 20 hp motor in star delta by changing leads in motor terminal box

    • rathnam chargeman 33 kv says

      for star delta starter you must change the main supply RYB TO YBR IT WILL BE OK

  62. sir
    I like to connect a Crompton greaves 15 HP Starter
    How to connect this.
    Starter identification 2 L3 3 L1
    L2 A1 B1 C1 1
    motor symbol. A1
    C2 A2 this type 6 connection place other 3 cant to identify how to connect 6 wires

    • sir mujhe dol controling and star delta controling ke bare me bataye mujhe tanki bhi smajh me nahi aata
      mai three years se elcectrician post me karyrat hu
      please jald bataye sir

  63. j.allaudeen says

    plg connection diagram with 3 contactors but i know control circuit diagram

  64. sachin says

    Sir plz send me star delta stater controlling diagram

  65. suresh says

    Sir.. recently i am in utter confussion as my 40hp motor is not pulling the load weight ie a primary jaw crusher.. which are confortably run by 30hp.. but unfortunate my motor could not carry any load although doing quite ok when the load is removed From it so can u kindly suggest any problems and remedies .. also kindly send me the wiring diagram from oil emersed starter to motor.. hoping for ur kind anticipation

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  67. i have to design a control panel .It consists of load from booth blower 7.5kw and electrical heater 135kw. what are suitable mccb.mpcb, current transformer ,MFM etc.How to select.

  68. Anton Roy Marlez says

    Good introdution,

  69. i nee to star delta conection

  70. What is the main starter turns of 230 v, 15 hp, and 1phase crompton greeves motor

  71. Ejiogo fabian says

    I indid gain something for your technical explanation. Keep it up.

  72. kumaran says

    i will connect the 3 hp crompton gear motor (conveyor), with the use of star delta starter or ordinary starter.

    • Hi, You can use DOL starter.But for the best practice,I suggest you to use Variable Speed Drive.You can control motor speed and energy efficiency

  73. santosh dhadke says

    Pls explain me 7.11 Hp 3 phase motor how much taken no load current?
    Also this motor is rewinding motor.

  74. Muwonge Joel says

    Hi sir, am very glad by your service. am an electrician working in a factory but am new in the field. i request u to give me lessons on my email, because am facing many challenges. am waiting for your service sir.

  75. Very educative and encoureging

  76. Rishikant sharma says

    help me please to know that conection of star delta moter panal
    givr me thesiggesion that how can we make a star delta moter panal

  77. afolayan tunde says

    star not changing to delter position, am not sure if timer is the problem

    • HI,
      Please check your control circuit first…make sure it work properly before you switch on the power cirucit…

  78. it was easy to understand

  79. thanks…..

  80. Sivashanmugam says

    Why we do delta connection in motor?

  81. rohit khare says

    Sir 3phase moter ka star connection kaisa Banta hai

  82. Rajasekar says

    Thank you

  83. EMAD HAMED says


  84. any company jobs me

  85. Dereje ayele says

    I like it

  86. star not taking running direct take delta what problem
    before some time both work.
    but this time only take delta.

  87. Dear sir!
    Please send me the way of how to select proper cable for desired load…

  88. M. Saleem says

    I want to know that will the star delta starter procedure operate for duel voltage motors ?such as if motor has 220 to 460/3/60 then either power can be apply on motor or there will be any difference in connections for 220 and 460 volts? regards.

  89. please tell me about star delta connections

  90. Hi,
    Iam chinmaya i want to know when connection in motor side in star delta i dont have to know The colour code then how to check in feeder side that connection should be ok or not.
    please Help me .

  91. Medhat says


    I have 37/22kw motor, and I want to connect it in star-delta connection, thank you to advice the rated current of main circuit breaker, main contactor, star contactor, overload.


  92. Star and main contactor become OPEN when shifting to delta.. why?

  93. Gud day sir, i’m a follower nd a lover of ur page. I am an engineering student and I have a very important question on a star delta motor connection.; wat wil be the effect of the below connection, wil it work normally, damage the motor or blow the fuses…?
    If main contactor is connected as; L1, L2, L3.
    Star delta contactor as; L1, L2, L3.
    While at motor end…
    Primary side; U1-L1, V1-L2, W1-L3 .
    Star delta
    Secondary side; W2-L2, U2-L3, V2-L1.
    I hope to get ur response soonest.
    Tanx 4 ur time nd wonderful job.

  94. s, s, kar says

    A squirrelsage induction motor has 6 terminals whose terminaltag is missing .how to identify u1,u2,v1,v2,and w1,w2, (start and finish of three windings)

  95. I like the training on star delta connection.

  96. Sankar says

    Sir i am electrican our company purshase crompton greave 10 hp motor and star delta starter . I am checked to wiring delta connected in a terminal to wiring for stardelta?

  97. karthikk says

    Dear sir how to working the star delta motor in without earth

  98. I love that you offer diagrams to help me know what exactly you are referring to in this system. I am just trying to acquaint myself with a few systems of industrial equipment and yours describes things in such a visual way that it makes it easier. I will have to try and use your system in my timer relays. Thank you.

  99. Richard W Robinson says

    I have an air compressor that has a Wye Start Delta Run start up. While doig some current tests we noticed 40 Amps more leaving the contactore than coming in on the mains. I would like to send you an attachment to better explain what we are showing but when you add what is going out on the two conactors it is more than what is coming in on the main conductors (one set of three). Can I send you my drawing?

  100. R.Jayachandran says

    How to check delta double star motor winding

  101. I need practical procedure for manually operated star delta starter

  102. waheed says

    how can I select a overload relay for the below rating motor
    7.5 KW
    220 Volt
    60 Hz

  103. Very nice post and straight to the point. I don’t know if this is truly the best place to ask but do you guys have any ideea where to hire some professional writers? Thank you

  104. hemant says

    If u1,u2,v1,v2,w1,w2 not available in wire or motor terminal .how will check u1,u2…..

  105. Nathan Cuna says

    I have a problem in selecting the motor voltage Rating for Star Delta Connection,
    I want to Buy a 45 KW Induction Motor but I’m confuse of what is the Voltage Rating that suitable for a Star Delta Controller? We have 380 Voltage supply Source, The motor Voltage Rating available are: 220/380 and 380/660 which is which, and Why? Please Help me find an answer in this matter…..

  106. isaiah mazy says

    what is the recommended time to be set for a star delta timer

  107. Keshavkalige says

    Sir ,
    If I change main supply R and B then the built-in auto starter does not work . how to solve this

  108. Sujeet mishra says

    sir 3phase induction motor ke connection me kitne wire connect hote hai.
    isme three phase RYB ke alawa Nutrul bhi add hote hai kya
    pls sir confirm kariye
    reply sir pls on email id / mobile no. 9412619197.

  109. rolando franco says

    Please quote
    1 pc. Control panel connection wye-delta y-a 20hp, 220v, 3phase 60hz
    W on/off light indicator switch (red/green) with overload protector. Lock and terminal (L1/L2/L3/N/EARTH GROUND)
    ROLLY/MANIL AOVERSEAS INC. TEL;6382004227 FAX;6328004172

  110. Technicnian says

    Video from connection of 30 kw motor in production:

  111. We have connected (3-core double cable ) 6-lead to 20hp motor junction we have to measure the no load or full load, as there is 6-wire so shall we average out the 6-reading for no load ? Or we have to take with 2-wire at a time.

  112. Sir,

    Good day!

    Normally as per diagram of Wye-Delta Starting – U1, V1 & W1 are connected in the Main Contactor.

    What will happen if – U2, V2 & W3 are connected in Main Contactor? Then – U1, U2, W2 are connected in the Delta Contactor?

    Hope someone can share their experienced if they encounter this kind of connections.


  113. Novatus says

    Dear sir I want to know about U1,V1,W1 and U2,V2,W2 how can i measure and realize them if the motor have not marked.
    Please I need ur help

  114. obunwa Ernest uche says

    Hello please I want to know, what is required to change start to Delta star connection and its implications

  115. Hi,Dear Mr/Mrs
    I have a quastion about Delta &Star connection.Well 37kw motor(nameplate) 380/660v Dela and the voltages supplier is 380 v. Now does it logical to run motor with Delta &Star.On the contrary , 37kw 380/660v Delta /Star runs with just Delta connection.
    I am looking forward hearing from every one.
    Best Regards

  116. i have the same case with this question.
    And you must set very carefully for your thermal overload relay.


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