Motor Starter Explained | Motor Starter Types

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⌚Timestamps:
00:00 - Intro
00:43 - Motor starter types
01:39 - 1) FVNR
02:13 - 2) FVR
02:55 - 3) Reduced voltage
03:26 - 4) Multi-speed
03:49 - 1) Manual motor starting
04:10 - 2) Magnetic
04:36 - 3) Auto-transformer
05:20 - 4) Star-delta
05:55 - 5) Soft-starter
06:15 - 6) VFD
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Most digital outputs on control systems operate on 24 volt DC or 120 volt AC. So how do we start and stop three-phase, 480 volt AC industrial motors? The simple answer is by using a motor starter.
All motor controllers are designed to keep the motor from being energized until the controller is told to activate. Once activated, current can pass to the motor, which energizes the motor windings and starts motor rotation.
Motor controllers are also referred to as motor starters. These devices are most often offered in a single unit with circuit disconnecting means, a contactor or other type of motor actuator, circuit overload protection, and motor overload protection.
Motor Controllers can be grouped by starting method and by starter type.
1) Full Voltage, Non-Reversing (FVNR)
The first starting type is the Full Voltage, Non-Reversing motor controller. As the name implies, when the controller’s single contactor actuates, this motor controller type, also known as FVNR, allows the full line voltage to be applied to the motor.
2) Full voltage reversing
In a Full Voltage Reversing motor controller, the controller has two separate actuating states:
- One to operate the motor in the forward direction, and
- One state to allow the motor to operate in the reverse direction.
This is accomplished by adding a second contactor.
- The forward contactor acts the same as in the FVNR, and
- The reverse contactor swaps the position of two of the phases.
3) Reduced voltage
The third type of motor starting method is called reduced voltage starting. Large motors can have a very high starting current that may be harmful to the motor or the motor controller itself.
4) Multi-speed
The last type of motor starting method is multi-speed. Multi-speed motor controllers use solid-state or transforming means to allow motors to be controlled at different speeds. Two of these methods, Variable Speed Drive and 2-speed control will be described later.
Now that we have described the four major categories of the motor controller by starting method, we will now describe the six major motor starter types.
1) Manual
The first is manual motor actuation, which requires an operator to switch the motor on and off.
Due to safety considerations, manual motor starting is limited to the motor of 10 horsepower or less. They can be used on single or three-phase applications.
2) Magnetic
Magnetic motor starters, or direct online starters, are the most common single-speed starter type.
For magnetic starters, a pushbutton or a selector switch connected to a PLC digital input is used to activate a PLC digital output. The PLC output will pull in a coil that magnetically holds the starter contacts closed, allowing current to pass to the motor.
Magnetic motor starters are used with FVNR and full-voltage reversible motor controllers.
3) Auto-transformer
Auto-transformer motor starters are commonly used in reduced-voltage starting applications, especially with large motors.
4) Star-delta bit.ly/3pAPSyq
Star-delta reduced voltage motor starting is related to auto-transformer starting in that three separate contactors are used in the motor control scheme.
5) Soft-starter
Soft-starters are another method used for limiting starting current. Soft-starters use solid-state electronics to limit the startup voltage and current.
A soft-starter allows the voltage to gradually increase during motor startup. This allows the motor to slowly accelerate & gain speed in a controlled fashion.
6) Variable frequency drive (VFD)
A variable frequency drive, or VFD, is similar to a soft-starter but allows the speed of the motor to be varied by varying the frequency of the output to the motor.
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[@MrWaalkman]

Probably the best explanation that I have seen on the various ways of starting a 3 phase motor!

[@realpars]

That's amazing to read! Thanks for sharing.

[@inothome]

Hahaha, you guys fixed the open main contactor in the star - delta explanation. I caught that yesterday, kudos for the re-upload.

[@realpars]

Yesssss! Didn't want to mislead people around the world! :))

[@DinkyDoughnut]

Thanks, Handy to know for my study in motor control.!

[@user-wr8he6be3t]

Once again you just upload a very helpful video, that can help a lot of technicals Around the globe. Thank you real pars team. 👍🤞🙏

[@realpars]

Thanks a lot for your kind compliment! We are always extremely happy to hear such positive feedback! If you ever have any questions, feel free to reach out to us. Happy learning!

[@fernandovillon1258]

Excellent video! Would also like to watch a series about MCCs: basics, applications and manufacturers' history.

[@realpars]

Hi Fernando, Thanks for your comment and your suggestion. I will pass this on to our course developers! Thanks for sharing and happy learning!

[@ahmadjabir6105]

The World needs more people like you Thank you so much

[@realpars]

Our pleasure, Ahmad!

[@gopalkrishnan8411]

Thanks for sharing video. Your way of explanation is good like animation of pictures and videos. And also clear explanation about that content....

[@realpars]

You are most welcome!

[@molinschado1987]

better than the other videos,thanks realpars

[@realpars]

Glad you liked it!

[@javierferrer4634]

Excelente vídeo! Thank you for sharing.

[@realpars]

Our pleasure!

[@ecotech4148]

Thank You RealPars

[@realpars]

You're very welcome!

[@matthewrenshaw]

Just phenomenal

[@tuanano9007]

Perfect! Thank you so much!

[@realpars]

Our pleasure!

[@dotex2809]

Best and the Beast of the field

[@ahmedimam721]

Very helpful thank you so much

[@realpars]

Great to hear that, Ahmed!

[@aaristo97]

Nice ! Thanks for sharing

[@realpars]

You're very welcome!

[@toastonryeYT]

Good stuff, helpful!

[@realpars]

Glad to hear!

[@kurtg5645]

Might be the best animation I've ever seen, kind of curious what software is used to produce such a great animation.

[@realpars]

Thanks for your kind comment, Kurt! I am actually not sure about that as this is done by our Graphic and Animation department. Curiosity will remain :).

[@dotex2809]

if you went to realpars site to see their team behind this courses , you will figure out that they have different skills like illustrator , photoshop , after effect and power point (in the old videos ) and animations designers , you can say they have different skills in a lot of software's and use the suitable method for what they want , see plc first video you will find they used only power point

[@Electricalsupervisor]

Excellent

[@danielteyehuago1633]

Thanks for your sharing it with us. This is a great tutorial and very informative... dl

[@realpars]

Thanks for watching!

[@danielteyehuago1633]

@@realpars welcome

[@KarigorEngineeringTechnology]

Nice explanation!

[@realpars]

Thank you! Glad that it was helpful

[@johnlansing2902]

Thank you.

[@realpars]

Our pleasure, John! Happy learning.

[@nimbo9492]

Thank you for the well detailed video. 👍 As an HVAC Application engineer, i have come across projects where asked to provided motor starter in bypass line of E-bypass vfds. Is this mainly for safety reasons in case of VFD failure? To my knowledge, most E-bypass VFDs already come with embedded motor starters in their bypass line, so i thaught it might be redundant to add an additional motor starter. Please correct me if i am wrong.

[@realpars]

Yes, having a bypass line with a motor starter (contactor) is a means to bypass the VFD and be able to continue to run the motor if the VFD fails. If the VFD package already comes with a bypass circuit, adding another bypass would not be required. However, sometimes you may need to add another contactor to be able to isolate the VFD if running in bypass. This is the K2 contactor in the diagram at the beginning of this article: www.esmagazine.com/articles/99352-in-hvac-vfds-is-2-contactor-bypass-really-better-than-3-contactor-bypass

[@nimbo9492]

@@realpars I appreciate the thorough response, thanks for your help!

[@jmnunnelee]

amazing video

[@realpars]

Glad you think so!

[@nabilou8106]

Awesome 😎👍 !

[@realpars]

Thank you, Nabil!

[@ruisilva3505]

TKs a lot

[@realpars]

You're very welcome!

[@tristanhubbard6520]

What is the triangle displayed in between the contactors at 2:54 in the video? Is it a mechanical Interlock?

[@realpars]

Thank you for your inquiry. Indeed, the symbol you mentioned represents a mechanical interlock. As emphasized in the video, it's crucial to avoid having both contactors in the "ON" position simultaneously. Doing so can result in a dead short within your circuit, potentially leading to a fire hazard. The triangle symbolizes this mechanical interlock feature. Happy learning!

[@xWillyHD]

So with a soft-starter, can you simple wire the motor in run (Delta)? instead than power the motor in start(wye) for a few seconds and then change to run(Delta)?, Talking about a 480v single-voltage motor

[@realpars]

Yes. Control of starting current in the case of a soft-starter is controlled by the device itself. There is no configuration using a soft-starter where the wiring configuration is changed as there is in a star-delta type starting scheme. This makes the use of a soft-starter simple from a wiring standpoint and very helpful in keeping the starting current in check.

[@joeclark6842]

I thought it was great, I wish you guys could make a video of you actually installing these systems, while explaining the diagram. I am currently going through my apprenticeship, and I always watch your videos on a subject. Plus Local 26 IBEW JATC uses your videos as training material, and my instructor is very strict about what he shows us on you tube, only the best at Local26

[@realpars]

Hi Joe, Thanks a million for your kind comment and support! I have happily gone ahead and shared your topic suggestion with our course developers. Hopefully they can create a future video course on that topic. Amazing to hear that Local 26 IBEW JATC is using our free KZbin videos as training material. We do have a couple of free video courses in our course library as well, have you seen those, yet? learn.realpars.com/courses/introduction-to-profibus learn.realpars.com/courses/PLC-Programming-MADE-EASY-Level-1 learn.realpars.com/courses/PID-Controller Happy learning!

[@bobcocampo]

What is the normal transition time for wye to delta starter

[@MrWaalkman]

Depends on the start up time. You've got to time it while it ramps up. And when you switch between star and delta you need to create a small delay when you turn off the star circuit before you turn on the delta circuit. Failure to do this will lead to a very bad day. www.gohz.com/motor-star-delta-changeover-time-delay#:~:text=In%20star%20Delta%20usually%20we,%2C%20to%20avoid%20short%2Dcircuit. The site mentions a 30 - 50 millisecond delay, That's pretty short if you ask me. It goes on to mention a 1 - 2 second delay. That's a saner option. Keep in mind that if your load takes a long time to start up, it will also take longer to stop. So a 1 - 2 second delay isn't going to hurt anything. And it is critical to include interlocks by way of contacts on each starter to prove that one starter has dropped out before bringing in the other. You also need to use a mechanically interlocked starter (a forward - reverse starter as seen @2:13) to mechanically prevent the starters from closing at the same time. Should both starters get engaged at the same time it's a phase-to-phase short, generally on a rather large feeder. Our plant had a 500 hp star-delta starter short out this way. It was an exciting day for our electrician.

[@realpars]

MrWaalkman is correct with his assessment. That said, a delay of 50ms (3-4 cycles) is normal for an open transition star-delta starter. I have heard of some people putting in an interposing relay between the Delta controller output and the delta run power relay. This can add about 30ms due to the pull-up time for the relay. Closed-transition starters of this type are best, but they are very expensive in many cases.

[@bobcocampo]

@@realpars How do you size the resistor in a close transition wye Delta starter

[@bobcocampo]

@@realpars How do you size up the resistor on a close transition wye start delta run starter?

[@bobcocampo]

@@MrWaalkman Is the time the same regardless on the size of the motor? Is there a table or a graph on how many seconds will a motor be on its rated speed when you start an induction motor?

[@roseelectronics4582]

Why was primary resistor method not included in the explanation? Good video though.

[@realpars]

Thank you for your question! To be honest, there are several types of motor starting methods that we did not cover, including primary resistance., Our videos are typically 6-8 minutes in length, and we have presented the methods that are most commonly used in the industry. Other types of starters also include rotor impedance, liquid resistance, use of chokes, as well as others. These are specialized methods not as widely used, but still very important in the uses they were particular designed for.

[@roseelectronics4582]

@@realpars thanks. that's some light into my knowlwdge.

[@focused353]

L2 goes to L2, why do we need a 3rd pole?

[@realpars]

Three poles = three phases (L1, L2, L3). In a 480VAC circuit, I need 3 poles to supply the motor, which each phase 120 degrees out of phase with the other poles. In 240VAC, I only need L1 and L2.