I'm going to pin my own comment here just to say... some of these comments are so interesting. You know what, it doesn't seem to matter how long I research these videos to make them as accurate as possible, there is ALWAYS more to learn and you guys open my eyes to things that I didn't know. The only problem is, I have to upload a video to learn these things! If only I could reverse time and learn these things before I design the video for upload! Impossible, but thanks for the valued comments you've added here. I'm hoping that everyone is benefiting including me! :)
Hi there. I'm new to motors and found this video great for my learning, it's very clear and concise. There is one thing, when the motor is at its desired speed, you said a contactor pulls in and removes the resistance on the windings in the panel. What tells this contactor to pull in? Is there a centrifugal switch or some form of switch somewhere? How does it know when to pull in?
Thank you for this easy to understand video. I have never known the workings of a slip ring motor before because I've never needed to. Now my education is complete!
Me included! But it's these situations that I put myself in that means I have to research how these machines work and I too learn massives amount of stuff (probably that I didn't NEED to know haha!)
I know it has nothing to do with this particularly video but since we are / I’m in quarantine, I’m doing a mrmattandmrchay marathon, rewatching all your videos to get the time by. 😅
To be, I consider that to be an excellent idea haha! If you could just watch them enough to get me a million views then that'd be superb!! haha, just joke. Thanks very much for watching my videos :)
The motor design reminds me of the wood working machines that we had at school in the workshop. They ran at 415 volts and you couldn’t let them run at full speed from a cold start. They all had a special start up and turn off sequence where there was a third state on the on/off dial. If you turned them on too quickly, the circuit breaker / fuse box would trip. Every machine had it’s own fusebox as well.
Ooh yes I remember seeing a pump (à wastewater pump or something) like that too! If you got the sequence wrong, you blew the fuse! It was really long to start (like you first had to press a switch, then push a certain button and release the button after 20 seconds), it was very unusual to say the least. It was later ripped apart with a assembly of programmable logic controllers, now all you have to do is flick a switch and the PLC will do the rest...
The sequence is actually correct. For this setup the time the resistors need to be in circuit is extremely short, less than 1 second. This is common in small (yes, this IS a small one) AC motors which are used for inching (i.e. repeated starting and stopping) as is commonplace in this lift when someone is lining up a floor. The starter in this case is not there to provide more torque but provided to limit the initial stalled inrush current in order to comply with the supply authority regulations. Yeh the time could be a little longer but it's clearly working correctly in this configuration. As soon as the rotor moves it's no longer stalled and so its fine to go straight to DOL operation which provides plenty of torque through the geared drive.
I know 9/10 of naff all about lifts. I know roughly how motors work so, there's that. But you clearly conveyed the use of slip ring motors, how they operate, their advantages and show them in action. I love these videos because of their quality and this one is no exception. Looking forward to the next one 👍
Looking at the sequence at 04:55 I'm getting the impression that RC1 might be cutting in too quickly, not giving the field in the rotor enough time to gain synchronisation with that in the stator, though I see another comment suggests this _is_ indeed correct and is to do with inrush current limiting, rather than efficient motor start-up. 😇 Either way, this is a fantastic video chaps! I've been into HV/HC electrics for _years_ (Though for my sins the most I ever get to play with is my own 240v single phase stuff) and stuff like this is always as educational as it is entertaining. It's when you think _very_ carefully about stuff like this motor you can come to understand the seemingly _very_ strange 16,666Hz phasing of overhead traction supply on German railways - 16,666 equals 50Hz/3 of course! 🚆⚡🇩🇪😁
Love your lift videos mate. The idea of the resistors in the motor is to reduce its power on startup, a motor will produce max torque at locked rotor or startup. As the motor speeds up and reaches its rated speed the torque is less. Starting an electric motor which is coupled to a heavy inertia load like a lift will cause it to overheat trying to overcome inertia, so by adding resistors we reduce the amount of power the motor can consume and make. This limits the electrical demand and a bit like a soft start for the mechanical parts. Electrically it’s easier too because the rotor currents will be less than the stator so smaller resistors and switching components. Hope this helps. All the best.
this was so interesting to watch! Im learning about electro motors in my studies, but hard a hard time visualising what was going on. This was a perfect help! Great explanation!!
Note that the rotor resistances can be used for speed control as well as just for starting. For applications like traction motors, it was common to throw added resistances into the rotor in order to run the motor with high amounts of slip.
first the video was private the other day and I'm like dammit! I check again now I'm like whoohoo! can you make a playlist of the motor rooms? that's the best part of your videos.
yeah, I made a big error calling the rotor an armature! Adjusting the visuals wasn't that difficult, but then I had to re-do ALL the voiceovers and make the video match the new voice overs. Mostly the same words, but different lengths - ARGGGH added 1 day's editing!
Being a motor is essentially a rotating transformer, increasing the resistance of the rotor windings (adding the starting resistors) decreases the current of the stator windings. Once the motor is rotating, removing the resistance provides the motor to run at rated power and torque.
I don't get why there is torque when the resistors are in the circuit. OK, there is AC induced in the rotor windings, because there is AC in the stator windings and the resistance in the rotor windings is finite. How do we figure out the phase relationship between stator and rotor? This would be necessary to predict the direction of the torque. Is the bottom-line explanation for the use of the resistors, as someone commented, just to limit current during startup? Or do they really increase torque as well?
Do best transition time from resistance connection to shorting coils depends on motor size/power or resistances or both? I appreciate the time you put into sharing this knowledge
@@markh5210 I'm in North America. Working on imported machinery from Europe (German, British, and Italian,) I've seen 3ph BRN/BLK/BLU, GRY/BLK/BRN, YEL/BRN/BLK. North America is RED/BLK/BLU for lower voltages and ORG/BRN/YEL for higher voltages. Canada and the US are approximately the same, but sequencing is different.
Yes, this is something else that I learnt from this video from the comments. I'm still old-skool haha! HOWEVER, not sure that grey/black and brown would have shown up as much as red/yellow/blue does in the visuals :)
Yes, this is something else that I learnt from this video from the comments. I'm still old-skool haha! HOWEVER, not sure that grey/black and brown would have shown up as much as red/yellow/blue does in the visuals :)
Great video! But there is an inaccuracy: the rotor speed NEVER catches up with the synchronous speed and the difference between rotor speed and synchronous speed is called "slip", which makes the rotating magnetic field of the stator sweep round and round through the surface of the rotor, induce electromotive force to let electric current flowing in the rotor circuit. If the rotor rotates at synchronous speed, NO torque is created, because there is NO electromotive force and NO current through the rotor circuit.
yep, I made a big error calling the rotor an armature! Adjusting the visuals wasn't that difficult, but then I had to re-do ALL the voiceovers and make the video match the new voice overs. Mostly the same words, but different lengths - ARGGGH added 1 day's editing!
I'm going to pin my own comment here just to say... some of these comments are so interesting. You know what, it doesn't seem to matter how long I research these videos to make them as accurate as possible, there is ALWAYS more to learn and you guys open my eyes to things that I didn't know. The only problem is, I have to upload a video to learn these things! If only I could reverse time and learn these things before I design the video for upload! Impossible, but thanks for the valued comments you've added here. I'm hoping that everyone is benefiting including me! :)
@Worlds largest Culvert theatrical Poster for poltergeist 3 by chris zabriskie.
Hi there. I'm new to motors and found this video great for my learning, it's very clear and concise. There is one thing, when the motor is at its desired speed, you said a contactor pulls in and removes the resistance on the windings in the panel. What tells this contactor to pull in? Is there a centrifugal switch or some form of switch somewhere? How does it know when to pull in?
@mrmattandmrchay What type of wave is beetween the rotor phases. Is it an AC sine wave or DC wave?
Thank you for this easy to understand video.
I have never known the workings of a slip ring motor before because I've never needed to.
Now my education is complete!
Me included! But it's these situations that I put myself in that means I have to research how these machines work and I too learn massives amount of stuff (probably that I didn't NEED to know haha!)
I am glad youtube channel like yours exist. Cheers
I know it has nothing to do with this particularly video but since we are / I’m in quarantine, I’m doing a mrmattandmrchay marathon, rewatching all your videos to get the time by. 😅
Mike i386 Great idea. His old videos can be interesting too! :-)
To be, I consider that to be an excellent idea haha! If you could just watch them enough to get me a million views then that'd be superb!! haha, just joke. Thanks very much for watching my videos :)
This video is great! Greetings from germany
Hey ein Deutscher 😂
Hey, thanks Matze!
The motor design reminds me of the wood working machines that we had at school in the workshop. They ran at 415 volts and you couldn’t let them run at full speed from a cold start. They all had a special start up and turn off sequence where there was a third state on the on/off dial. If you turned them on too quickly, the circuit breaker / fuse box would trip. Every machine had it’s own fusebox as well.
Ooh yes I remember seeing a pump (à wastewater pump or something) like that too! If you got the sequence wrong, you blew the fuse! It was really long to start (like you first had to press a switch, then push a certain button and release the button after 20 seconds), it was very unusual to say the least.
It was later ripped apart with a assembly of programmable logic controllers, now all you have to do is flick a switch and the PLC will do the rest...
@@Alexis_du_60 @dykodesigns2yt Both very interesting comments! Yes, makes sense!
The sequence is actually correct. For this setup the time the resistors need to be in circuit is extremely short, less than 1 second. This is common in small (yes, this IS a small one) AC motors which are used for inching (i.e. repeated starting and stopping) as is commonplace in this lift when someone is lining up a floor. The starter in this case is not there to provide more torque but provided to limit the initial stalled inrush current in order to comply with the supply authority regulations. Yeh the time could be a little longer but it's clearly working correctly in this configuration. As soon as the rotor moves it's no longer stalled and so its fine to go straight to DOL operation which provides plenty of torque through the geared drive.
I know 9/10 of naff all about lifts. I know roughly how motors work so, there's that. But you clearly conveyed the use of slip ring motors, how they operate, their advantages and show them in action. I love these videos because of their quality and this one is no exception. Looking forward to the next one 👍
COOOOL!, Thanks for the very nice comment :)
I love your chanel because of grate interesting videos that I learn from them 😁. I'm from the UK Buckinghamshire
Cool, thanks for watching! What part of Buckinghamshire are you from? I'm in High Wycombe.
@@mrmattandmrchay Aylesbury. I thought you lived further than that.
Looking at the sequence at 04:55 I'm getting the impression that RC1 might be cutting in too quickly, not giving the field in the rotor enough time to gain synchronisation with that in the stator, though I see another comment suggests this _is_ indeed correct and is to do with inrush current limiting, rather than efficient motor start-up. 😇
Either way, this is a fantastic video chaps! I've been into HV/HC electrics for _years_ (Though for my sins the most I ever get to play with is my own 240v single phase stuff) and stuff like this is always as educational as it is entertaining. It's when you think _very_ carefully about stuff like this motor you can come to understand the seemingly _very_ strange 16,666Hz phasing of overhead traction supply on German railways - 16,666 equals 50Hz/3 of course! 🚆⚡🇩🇪😁
Interesting comment and thanks! I too learned a lot when I was researching this video, never knew what a slip ring motor did before that.
Love your lift videos mate. The idea of the resistors in the motor is to reduce its power on startup, a motor will produce max torque at locked rotor or startup. As the motor speeds up and reaches its rated speed the torque is less. Starting an electric motor which is coupled to a heavy inertia load like a lift will cause it to overheat trying to overcome inertia, so by adding resistors we reduce the amount of power the motor can consume and make. This limits the electrical demand and a bit like a soft start for the mechanical parts. Electrically it’s easier too because the rotor currents will be less than the stator so smaller resistors and switching components. Hope this helps. All the best.
Excellent video👏👏👏👏
Very well edited and explained video ! Thank you !
Thank you for sharing your knowledge
good explanation, we love slip ring motors ;-)
thanks! :) Hope I did them some justice!
this was so interesting to watch! Im learning about electro motors in my studies, but hard a hard time visualising what was going on. This was a perfect help! Great explanation!!
Note that the rotor resistances can be used for speed control as well as just for starting. For applications like traction motors, it was common to throw added resistances into the rotor in order to run the motor with high amounts of slip.
This video is pure gold Thanku sir 👏
wow, thanks very much for the comment :)
Pretty nice. Thank you very much
first the video was private the other day and I'm like dammit! I check again now I'm like whoohoo! can you make a playlist of the motor rooms? that's the best part of your videos.
yeah, I made a big error calling the rotor an armature! Adjusting the visuals wasn't that difficult, but then I had to re-do ALL the voiceovers and make the video match the new voice overs. Mostly the same words, but different lengths - ARGGGH added 1 day's editing!
NICE. TOP NOTCH AS USUAL !!!!!.
very easy to follow as well.
@@SamSitar Yes, it should be class room material. Trying to explain this without this video will take way longer and not so clear.
Cool, thanks for the comment :)
Why is the motor not running as it should. Does a timing component need replacing?
Possibly, or an engineer not knowing what they are for had adjusted them incorrectly.
Being a motor is essentially a rotating transformer, increasing the resistance of the rotor windings (adding the starting resistors) decreases the current of the stator windings. Once the motor is rotating, removing the resistance provides the motor to run at rated power and torque.
That's a brilliant comment and observation!
Thank you sir very nice, sir elevator motor - rotor and coil Replacement video can I find
Hai sir iam nsivaramakrishna thanks again your time with the class prasnet my role
Amazing , thanks a lot
Nice.
thanks
These windings are in delta, how can the stopping jerk is maintained in these machine special in up travel with balance load, is there roll back felt.
Help full 🙏🙏
cool thanks.
Did you manage to fix or time those relays up so they started up correctly?
Hai iam nsivaramakrishna thanks again
Great video :) do you have a picture of the slip ring? Would it need to support all the motor amps as the stator?
I don't get why there is torque when the resistors are in the circuit. OK, there is AC induced in the rotor windings, because there is AC in the stator windings and the resistance in the rotor windings is finite. How do we figure out the phase relationship between stator and rotor? This would be necessary to predict the direction of the torque. Is the bottom-line explanation for the use of the resistors, as someone commented, just to limit current during startup? Or do they really increase torque as well?
Do best transition time from resistance connection to shorting coils depends on motor size/power or resistances or both?
I appreciate the time you put into sharing this knowledge
3 Phase circuits are now coloured Brown/Black/Grey with Blue as the neutral.
Phase identification colors and sequence vary depending on supply voltage involved and the country you are in.
@@abpsd73 BBG is the current UK/EU colour scheme (replacing RYB in the UK).
MMMC is a UK based channel.
@@markh5210 I'm in North America. Working on imported machinery from Europe (German, British, and Italian,) I've seen 3ph BRN/BLK/BLU, GRY/BLK/BRN, YEL/BRN/BLK. North America is RED/BLK/BLU for lower voltages and ORG/BRN/YEL for higher voltages. Canada and the US are approximately the same, but sequencing is different.
Yes, this is something else that I learnt from this video from the comments. I'm still old-skool haha! HOWEVER, not sure that grey/black and brown would have shown up as much as red/yellow/blue does in the visuals :)
In the U.S. the three phases of power are coded black, red and blue.
1:27 it creates a rotating magnetic field, not electric field.
The colours have changed in 2004 from red, yellow and blue to grey, black and brown
Yes, this is something else that I learnt from this video from the comments. I'm still old-skool haha! HOWEVER, not sure that grey/black and brown would have shown up as much as red/yellow/blue does in the visuals :)
neat
maintain quality as well as quantity
Great video! But there is an inaccuracy: the rotor speed NEVER catches up with the synchronous speed and the difference between rotor speed and synchronous speed is called "slip", which makes the rotating magnetic field of the stator sweep round and round through the surface of the rotor, induce electromotive force to let electric current flowing in the rotor circuit. If the rotor rotates at synchronous speed, NO torque is created, because there is NO electromotive force and NO current through the rotor circuit.
Waduh aku entok tugas tekok dosen tentang iki su
So the shorting is just a bypass.
yep, but bypass is more an American word. I work with electronic systems for my job and train engineers, and I always refer to it as 'shorting'.
Please sir give me diagram
The only diagrams I have are shown in the video
Uploaded twice (:
yep, I made a big error calling the rotor an armature! Adjusting the visuals wasn't that difficult, but then I had to re-do ALL the voiceovers and make the video match the new voice overs. Mostly the same words, but different lengths - ARGGGH added 1 day's editing!
mrmattandmrchay oof
Only star-delta and autotransformer starters work with slip-ring motors. VFDs and soft starters don't work
Interesting technology. Not really relevant nowadays as most elevators use either a VFD or simple two speed motors.
First
Way tooo FAST