Autotransformer Motor Starter

In this video I cover the basics of an autotransformer motor starter used as a reduced voltage starting method for a 3-phase induction motor. This video covers the schematic diagram and sequence of operations.
To view a Autotransformer Demo: • Autotransformer Starte...
For other videos on motor starting methods:
Part-winding starter: • Part Winding Motor Sta...
Wye-delta starter: • Wye-Delta Motor Starter
3-phase motors Playlist: • 3-Phase Motors
Magnetic Controls and Switching Playlist: • Magnetic Controls and ...
#RVS #Autotransformer #Starter

[@daveb9370]

This was a great video. Thank you. Working on an old hog grinder (200 HP) that welded one week old contacts by single phasing of the AT contactor. I didn’t understand it until my ultra smart contractor friend came to look at it and briefly explained it. Old ITE contactors in this thing, probably early 80’s. Going to simplify it with an ABB PSR 300 soft start. Much simpler and cheaper than replacing two contactors. Thank you for the great explanation.

[@davidkaytor7142]

Great video on AT motor starting!

[@HrFabio]

Great video mate! Thanks a lot. Amazing how you can write inverted effortlessly.

[@Xxxcappie23]

Good job explaining, this topic can get complex and ugly to explain. Hats off to you.

[@TagalogElectricaltips]

thanks for sharing Zack

[@angelofttv2661]

thank you . it helps a lot😊😊

[@sitiatikah7906]

Great video .. many thanks

[@ZackHartle]

Glad you enjoyed it

[@bodyulsergiy5808]

Thanks

[@jpowell36294]

Wow your videos have helped immensely as a supplement to the material I'm already studying in my third period of school. Great job and full props to you. Do you teach? If you don't you should because your approach is definitely straight to the point and well explained.

[@ZackHartle]

That's great that the videos helped! Thanks for watching! Tell your friends!

[@sd5722]

Nice

[@fakhrulislam5370]

Excelent

[@ioannisgalanos7911]

Hello. your video is very good. An Auto Transformer connection is basically useful to transform the voltage and amperes, for starting easily. I want to ask you, first of all the S1 and S2 are being energized . The voltage passes through the whole transformer and when it turns from L1 to L2 from the coils of the motor, does it pass again through the half of the winding of the transformer?? And later what happens exactly when a small part of the winding of the transformer continues connecting? I was thinking that the last part means that the motor ''reads'' all winding of the transformer, so you have more voltage/Amperes and the motor takes more power. The last pass is easy to understand because only the main contactor was energized .

[@reggenconde2391]

Hi! In which application are we going to use the open and close transition.?

[@michaelsagawa6179]

cool video but i have a question. why is the wye point essential so that the auto transformer acts like an autotransformer and not some line series line reactor??

[@jonathansenf7788]

My buddy and I are debating right now. Is your wedding ring and watch on your left hand or right hand? Lol

[@larry454]

Good day..what will happen if R is closed and S2 and S1 is closed too.??or there a delay of opening in S2 and S1 .??hope you answer my question.

[@shallwepass]

Nice vedip good job

[@mohanjayaraj5528]

Good explanation about line current and motor statring current. Thank you very much

[@ZackHartle]

Glad you liked it

[@sandeepsukumar1845]

What would the inrush current of the autotransformer be in this case. Would that compound with the starting current of the motor during start-up when S2 closes?

[@sandeepsukumar1845]

@@ZackHartle My thought process was; When S2 is closed, isnt that energising the transformer which is then energising the motor at reduced voltage at the same time before R is closed. So wouldnt the inrush current seen at the supply be a sum of transformer inrush plus the reduced voltage motor starting current?

[@jasonery5870]

Hello, there u need to correction a bit. Practically when u on the circuit it will energized the S2 contactor , timer relay and S1 contactor. After 10 seconds S1 contactor and S2 contactor de-energized same time timer relay will inject power to R contactor. But there is no working cause R contactor self holding missing....

[@lionelj8106]

at 6:35 to 6:45 .. why the holding contact TR instantly closed after the Timing Relay(TR) activated, whereas the normaly closed TR TO have to wait for the timer to finish count to open. is it the same timing relay they refers to?

[@lionelj8106]

@@ZackHartle so the TR Inst will not open even when the timer finished timing?

[@lionelj8106]

Thank you

[@markwilliams4525]

What happens if the 3 transformer leads on starter 1 are not tied together? I'm working on one now where they are not tied together but it still works

[@markwilliams4525]

@@ZackHartle I do appreciate your response to my question. I wasn't sure if it would be better to tie the bottom lugs of the contactor together or not

[@markwilliams4525]

@@ZackHartle will do! I greatly appreciate you taking time to answer my questions. Thanks

[@mr1bienvenu1]

If I run a 240v 3 phase motor on 208v it will draw MORE current, not less. So how is putting lowered voltage to a motor through an autotransformer going to make your motor start at a reduced current? Unless it acts like a reactor and limits the inrush current like some sort of choke.

[@mikemazzantini6397]

I believe this has to do with motor slip and running it below it's rated voltage. Run that motor with 120V and you'll see a lower current draw and the motor will run a lot slower.

[@amossimango9984]

What is taking S2 out of circuit ie wat is deenergising it?

[@ZackHartle]

Once the R coil is energized, it opens contacts before the S2 coil and de-energizes it

[@amossimango9984]

@@ZackHartle OH thank you l had not seen the R contact before S2

[@kapasmuka9115]

Step up right? Not step down?

[@ZackHartle]

It is stepping down the voltage applied

[@vitaliivarvaruk7663]

The video is not loading. What happened?

[@MUKESHKUMAR-zu9db]

📢 Please wear black shirt...