Impedance doesn't decrease with a decrease in frequency? Never Knew. Higher voltage windings don't produce more torque for a given current? Better call up the authors of my text books. Increasing stator winding voltage while holding frequency stable doesn't result in more torque? Wow these guys making these VFDs mustn't have a clue.
Don't bother. I don't even know where to begin to fix all your nonsense, neither do I see the need. There is more than enough people who made a youtube video while the same time being able to explain the inner workings of an induction motor with perfection and even accompanied with relevant math.
This video was actually meant to explain in a basic sense how an induction motor will behave when powered by a VFD. Sure, I admit this wasn't one of my better videos, but I think it does reasonably well for its intended purpose. It wasn't, however, meant to go into every detail of the induction motors operation. All that math is practically useless in the real world anyway. Maybe if your job is to design an induction motor is the math important. But as far as operating one I see no point going into the gory details. So as far as I'm concerned there isn't anything wrong with it. For me then it's quite simple. Increase V/F yields an increase in torque as long as the motor isn't saturated. Increasing the number of turns in the winding causes more impedance, which raises the V/F requirement but also reduces the current requirement. Maybe I'm a complete idiot but I don't see how that would be incorrect.
A good, informative video. One thing you forgot to mention is the core losses in an induction motor operated at high frequencies. Hysteresis and induced eddy currents in the core laminations will cause the motor to run very hot and limit its torque and speed at high frequencies. However, this usually isn't much of a problem in standard VFD applications.
Okay, after seeing the manual I can tell you several things you can do The base frequency adjustment for this drive is parameter is parameter P1.10, Field Weakening point. This adjusts when the drive will get to 100% of the rated voltage. Then Parameter P1.10 Field Weakening Point voltage, is the voltage it will output at the field weakening point that you have set. So, for example if your motor is 50Hz the drive will output full voltage at 50 Hz, but if you set P1.10 (continued)
Continuous high torque and low speed will require extra cooling, Continuous high speed will require rotor re-balancing and high performance bearings. Other than that, it should work. I usually install external cooling fans on my motors, so they can work with high torque. I have burned up a few motors by not using fans, but the one with the external fans all seem to be okay.
increase torque boost, lower base frequency and watch the temperature of the motor, it will increase. With a 1.1kW VFD, you could possibly burn out the motor if you aren't careful. For maximum torque, you want maximum current but since the speed will be lowered, so will the fan speed and it will give less cooling. An external fan is usually recommended
I will replace it, just wanted an experienced opinion.Thanks for the reply most of the web sites go straight to the deep technical stuff. I guess that's because most people doing research om this stuff are generally savvy on how such things work. I'm just a simple woodworker and you guys might as well be speaking Greek most of the time. Thanks again.
Good video, thanks for sharing! Have u seen a motor like this blow up due to overspeed? I have, and i would recomend u to increase your safety distance quite a bit next time!:)
You should be able to get the motor up to that speed, but use caution, the bearings may wear very quickly with continuous use. If you don't want to loose any torque, then you'll need to increase the voltage as well as the frequency. If the voltage is 220 at 50 Hz,then you will need 770 volts to achieve that speed with no torque loss. Power is constant, and power is a product of torque and speed. So increasing speed with the same power means less torque.
subcooledheatpump, If I put a VFD on a 120VAC 60 HZ 3600 RPM 1/2 HP Induction Motor will it allow Me to Turn the RPM up to 2x or 3x it's current Rated speed? Thank You for the Excellent video.
to 40 Hz then it will output full voltage at 40 Hz, that gives more current at a lower frequency and therefore more torque. You can also adjust the voltage when you are halfway to your field weakening frequency, parameters P1.12 and P1.13. Set P1.15 to 1 to enable torque boost, set P1.16 down to a minimum, yes this makes the motor loud but It reduces losses in the inverter and gives you more torque. Then parameter P1.4, if you set it to 2 X the motors current rating, you should get 2 x torque
I had wrench attached to the shaft that same motor once, that almost broke my arm. My arm was sore for weeks. I never played around with motors in the same way since
This was a 6 pole motor, so 350*20= 7000 RPM Induction motors can usually take 4x rated current, that means 4 times the torque. If you can keep the voltage up, you can get 4x torque at 2x speed to make an induction motor 8 times more powerful. Thats my theory anyway. I get 4x torque in my electric van with a 6 pole induction motor
These are normally parameters set on the VFD. What VFD are you working with? some types may not allow you to alter the output as easily It sounds to me as if you may be working with an ABB ACS type or similar drive. In that case you would enter all the values as they appear on your motor nameplate, then set the maximum torque to 300%. If this isn't the case, then you can usually find the parameters in the manual
Did you thing that increasing the volts up to 770 volts will not demage the motor ??and how many pole has to have motor to work beter ? once again thanks allot for your time !
I have a really basic question that no one is answering for me. Will a weak run capacitor cause a loss or torque? I recently bought a used wood shaper, it starts right up but stalls immediately when I put it under load. I can't say if it's running at full speed before this happens because I've never seen it run properly. I'm at my wits end and would greatly appreciate any help you can give me.
So, 350 Hz and I think this was a four pole motor? So that would be about 1750*6=10,000 RPM? It was interesting that the torque dropped so much that it stalled in the first test, then it held speed when wired for 240V. It should be possible to get at least 2x the rated HP by overclocking and keeping the V/F ratio. And you can usually overload an induction motor by 2x to 3x torque before breakdown and stall, so as much as 6x total HP. And maybe more with special windings.
You could do that, Set P1.10 to 25 Hz, then set P3.2 to 25 Hz. That would make the controller output full voltage at 25 Hz, and thus give the most possible current to the motor for the greatest torque, at half speed. Of course this assumes the overcurrent trip hasn't been set off. The only real problem is the motor would be overdriven technically, you would have to add an external fan, or you would destroy the motor.
I have a concrete block machine. It has a control panel set up for 40 amp, 220, 3ph. The machine has four motors rating from 2.2kw to 3 kw 1380rpm 50 hz.
That voltage probably will damage the motor, as it is likely beyond the windings' insulation rating. The number of poles in this case won't make much of a difference. A high speed motor, That is a motor which is rated for 10000 RPM would be more suitable, as it has bearings designed for high speed operation. It is likey that you can have the bearings changed for high speed, and you may be able to get the motor rewound for a lower voltage so you can achieve full speed with no torque loss
Is current independent of frequency and voltage or does the value of current remains constant with the change in frequency and voltage while operating induction motor with VFD? Because in my view current increases at low frequency and at low voltage to deliver same power. So this high current will eventually burn the insulation of the motor.
If the input voltage is 220 volts then the output voltage should be 220 volts at base frequency. Base frequency is the frequency at which the VFD will output maximum voltage, and it is programmable. So you can run a 220 volt 50 Hz motor at 300 Hz and 220 volts, but as I explain in the video you will lose torque. You could however, use a 400- 480 volt VFD, program the base frequency to 120 Hz, then run your motor at 300 Hz and 480 volts.
Ok , thanks for your fast reply. I have another concrete question. I have VFD brand omron VS mini j7 his input is 220 volt I want to use motor for spindle on 8-10000 rpm, Im planing to buy motor 220/380 volt 50hz 2,2kw 2860rpm acording to you experience is it possible to get about 3.5 times more rpm and how much torgue will I loose from this motor??My opinion is that it should work on about 175hz and I thing that I wont loose any torque? what do you thing about that ?
HI!!! I saw your video here and Im interested for use standard motor of 50 hz via VFD on 300 hz how much voltage is outgoing from VFD? input voltage is 220v how much is output voltage?? Sorry for my bad english Im writing from Macedonia :)
Sir may I asked your opinion , I want to install a VFD on my drill press what can you recommend on how many HP should I get for a motor , is it better to get a 3 phase motor and how much HP should I get and what VFD brand you recommend on the motor that will work on the VFD your going to recommend , thank you sir for your opinion and keep up the good work and more power to your you tube channel!
It all really depends on the drill press in question. It would certainly be better if you could use a 3 phase motor instead of a single phase motor. I have a drill press myself that I believe has a 3/4 HP motor. But again, this all depends on how big your drill press is and what you intend to drill with it.
Good day friend, I searching for answers and saw your video and I'm asking for some help. We are using a delta VFD-B to run a 25hp motor for a 250lbs washer extractor. I'm new to the whole thing so I set up some parameters to the best of my knowledge. The machine runs ok with just the basket and water but for some reason the motor won't spin when the machine is loaded with wash load. Can you help please?
Sure. So I take it this isn't a variable torque application, For example once loaded the load is fairly constant correct? If so, I would check the V/F Ratio. In other words, if the Motor wants to have 460 volts at 60 Hz, make sure the VFD is programmed to output that. If your V/F ratio is too low (for example, 240 volts at 60 Hz) it will stall the motor. Check that and let me know if you're still having problems. Thanks
Great video, I however can not seem to run my vfd without getting an over current fault. It trips off only a few seconds after start up. I have tried lengthening the start up and lowering the Hz. Any thoughts would be appreciated. Thanks
Thank you for this video, it is useful information. I am struggling trying to work out why I have little torque from a 50hz delta motor as in when connected to the VFD it spins as expected but can be stopped dead just by taking hold of the shaft with my hands. I have 4 motors and 2 work fine and the other 2 I just cannot get any torque from them and I would really like to know why. The VFD is 2.2kw 220v HuanYang VFD, it runs a 2.2kw spindle motor perfectly at 400rpm. I also have a 2.2kw 3 phase motor that is 50hz, the plate says 220v delta or 440v star and works perfectly well at 50hz delta of the HuanYang VFD I also have a 3/4hp 50hz Hoover motor that the plate says 220v delta or 440v star but when wired delta and ran at 50hz it is gutless and has very little torque and I do not understand why. Finally I have a SEW Eurodrive motor that is about 1/4hp that the face plate says 440v star, the wiring block inside can be changed to delta (although the face plate does not give specs for delta) and this also has no torque when running at 50hz delta The only difference I can see is that the 2 that work fine are rated at 2.2kw and the 2 that don’t run properly are smaller motors more like 1kw, but I cannot see why a 2.2kw VFD would not be capable of running a 1kw motor so I don’t think this is relevant. I would really like to know what I am doing wrong if you have any input
Small induction motors have high resistance windings. The high resistance windings drop a lot of voltage and reduce the current down too low to produce much torque. Most likely you need to increase the output voltage. You can either change the V/F ratio or add torque boost. Some VFDs call this "IR compensation"
Hi. Well, I am usign a motor that works at 60Hz and Im controlling it with the same VDF as you. I want to know if I can run the motor whith a frecuency higher than 60Hz due ti the VDF can run at 400Hz. Im not expert in the topic so I decided to reply you because at the momement just run the motor at 60Hz or less. I hope you answer as fast as you can.
Hi Jay, Did you find out why the smaller motors produced so little torque when run off of a larger VSD? I've had mixed fortunes running 3ph motors, in Delta, from budget cost Chinese single phase 240V in/240v out VSD's: 1) My old shaper machine with a 0.37kW 3ph motor ran fine, in Delta, on the default parameter settings of a cheap 0.75kW VSD . 2) But, a newer 0.55kW SEW motor, powered by the same 0.75kW VSD, produced almost no torque below 30Hz. I eventually bought a more expensive VSD and then the SEW motor worked OK. 3) I've also experienced a curious problem with a 0.18kW motor wired in delta, powered by the cheap 0.75kW VSD. It ran at 1/3 rated speed and became too hot to touch within less than a minute! The same motor ran fine on a real 3ph supply. Go figure!! Regards Paul in NZ
Question: What would you have to do for a motor to change its torque while mantaining constant its speed? And to change its speed while maintaining torque constant? As for example a vinyl turntable does
Variable frequency drives with torque control either read the motor speed directly with a tachometer (encoder,resolver or similar), or estimate using a motor model and by measuring the phase currents. From there, the vfd can adjust the torque to cause the motor to maintain constant speed even under varying load, this is done by adjusting the output voltage and frequency in realtime. A small computer inside the vfd calculates the difference between the commanded speed and actual speed and makes real time decisions as to what will best correct the error, but it's usually an adjustment to output voltage. Holding constant torque is similar but a little more complicated. The computer inside the VFD must again read a model of the motor but it must be a fairly accurate model of the motors flux torque relationship. From this, the computer can again make real time decisions as to what combination of voltage and frequency output will have the desired impact on the rotors flux. For example, a maximum torque command will cause the VFD to attempt to accelerate the motor as fast as possible, and this will cause the VFD to output maximum voltage, but the frequency will need to be determined from the motors actual shaft speed. (hence the tachometer). A half torque command probably wouldn't require the same output voltage, but would still need a good reading of the motor shaft speed.
So the thing that modifying frecuency, chances the spinning velocity of the inducted magnetic field whereas by modifying the voltage applied, you chance the inducted fields strength. Great data! Thank you for all the explanation!
it's not that motor does nothing at higher speeds it's because the rotation of rotor can't keep in sequence with the frequency of apply signal, thus rotor can't produce any rpm of rotation
i have a question can i use that speed controller to lower the speed of a motor that has 1700 rpm to 10 rpm? and keep using that 10 rpm for long periods of time?
Any 3 phase induction motor can be used with a VFD, as long as the VFD has the right output voltage and current capacity. Permanent magnet motors can be used but they usually require a encoder. Thanks for watching
what if we change the rotor of a induction motor (A.C) with permanent magnets... what will happen will it increase the torque and rpm or it will decrease?
Not necessarily. RPM should increase as it would match the synchronous speed without any slipping. Torque should increase per amp since magnetizing current is no longer required by the PM rotor. As long as the magnets are strong enough to resist being demagnetizied by the stator
subcooledheatpump Speed and torque would decrease exactly because a permanent magnet can not offer the same amount of push or pull. Introducing a permanent magnet is effectively to move the equilibrium to one side. That's why a DC design is about 10 - 15% less efficient when not taking this into consideration. A clever DC on the other hand is usually 10% more efficient than induction, but much more complex. Induction motors got complexity for free in the form of sinusoids.
thanks a lot 17 min video is better than 3 month course
I got more out of this video than all of the research I've done in the past 3 months. THANKS!!
That's kind of sad because just about every single point made in this video is false.
Impedance doesn't decrease with a decrease in frequency? Never Knew. Higher voltage windings don't produce more torque for a given current? Better call up the authors of my text books. Increasing stator winding voltage while holding frequency stable doesn't result in more torque? Wow these guys making these VFDs mustn't have a clue.
Don't bother. I don't even know where to begin to fix all your nonsense, neither do I see the need. There is more than enough people who made a youtube video while the same time being able to explain the inner workings of an induction motor with perfection and even accompanied with relevant math.
This video was actually meant to explain in a basic sense how an induction motor will behave when powered by a VFD. Sure, I admit this wasn't one of my better videos, but I think it does reasonably well for its intended purpose. It wasn't, however, meant to go into every detail of the induction motors operation. All that math is practically useless in the real world anyway. Maybe if your job is to design an induction motor is the math important. But as far as operating one I see no point going into the gory details. So as far as I'm concerned there isn't anything wrong with it. For me then it's quite simple. Increase V/F yields an increase in torque as long as the motor isn't saturated. Increasing the number of turns in the winding causes more impedance, which raises the V/F requirement but also reduces the current requirement. Maybe I'm a complete idiot but I don't see how that would be incorrect.
This was great. As a unofficial electrician this helped more than any vfd how to ive seen.
A good, informative video. One thing you forgot to mention is the core losses in an induction motor operated at high frequencies. Hysteresis and induced eddy currents in the core laminations will cause the motor to run very hot and limit its torque and speed at high frequencies. However, this usually isn't much of a problem in standard VFD applications.
I will be revisiting this video again and again. Thank you.
Thanx I look forward to seeing more of your videos you have a great grasp on theory that makes your explanation easy to absorb.
Okay, after seeing the manual I can tell you several things you can do
The base frequency adjustment for this drive is parameter is parameter P1.10, Field Weakening point. This adjusts when the drive will get to 100% of the rated voltage. Then Parameter P1.10 Field Weakening Point voltage, is the voltage it will output at the field weakening point that you have set.
So, for example if your motor is 50Hz the drive will output full voltage at 50 Hz, but if you set P1.10 (continued)
Continuous high torque and low speed will require extra cooling, Continuous high speed will require rotor re-balancing and high performance bearings. Other than that, it should work.
I usually install external cooling fans on my motors, so they can work with high torque. I have burned up a few motors by not using fans, but the one with the external fans all seem to be okay.
increase torque boost, lower base frequency and watch the temperature of the motor, it will increase. With a 1.1kW VFD, you could possibly burn out the motor if you aren't careful.
For maximum torque, you want maximum current but since the speed will be lowered, so will the fan speed and it will give less cooling. An external fan is usually recommended
I will replace it, just wanted an experienced opinion.Thanks for the reply most of the web sites go straight to the deep technical stuff. I guess that's because most people doing research om this stuff are generally savvy on how such things work. I'm just a simple woodworker and you guys might as well be speaking Greek most of the time. Thanks again.
It was a great learning from you, quit educative
Good video, thanks for sharing!
Have u seen a motor like this blow up due to overspeed? I have, and i would recomend u to increase your safety distance quite a bit next time!:)
Excellent video!!
You should be able to get the motor up to that speed, but use caution, the bearings may wear very quickly with continuous use. If you don't want to loose any torque, then you'll need to increase the voltage as well as the frequency. If the voltage is 220 at 50 Hz,then you will need 770 volts to achieve that speed with no torque loss.
Power is constant, and power is a product of torque and speed. So increasing speed with the same power means less torque.
subcooledheatpump, If I put a VFD on a 120VAC 60 HZ 3600 RPM 1/2 HP Induction Motor will it allow Me to Turn the RPM up to 2x or 3x it's current Rated speed? Thank You for the Excellent video.
Very nice explanation
to 40 Hz then it will output full voltage at 40 Hz, that gives more current at a lower frequency and therefore more torque. You can also adjust the voltage when you are halfway to your field weakening frequency, parameters P1.12 and P1.13. Set P1.15 to 1 to enable torque boost, set P1.16 down to a minimum, yes this makes the motor loud but It reduces losses in the inverter and gives you more torque. Then parameter P1.4, if you set it to 2 X the motors current rating, you should get 2 x torque
I had wrench attached to the shaft that same motor once, that almost broke my arm. My arm was sore for weeks. I never played around with motors in the same way since
Yeah I'm back mate. So glad to still be friends,
.ya a star on here" ya channel is awsome!!! ;-)
This was a 6 pole motor, so 350*20= 7000 RPM
Induction motors can usually take 4x rated current, that means 4 times the torque. If you can keep the voltage up, you can get 4x torque at 2x speed to make an induction motor 8 times more powerful. Thats my theory anyway. I get 4x torque in my electric van with a 6 pole induction motor
These are normally parameters set on the VFD.
What VFD are you working with? some types may not allow you to alter the output as easily
It sounds to me as if you may be working with an ABB ACS type or similar drive. In that case you would enter all the values as they appear on your motor nameplate, then set the maximum torque to 300%.
If this isn't the case, then you can usually find the parameters in the manual
Did you thing that increasing the volts up to 770 volts will not demage the motor ??and how many pole has to have motor to work beter ? once again thanks allot for your time !
I have a really basic question that no one is answering for me. Will a weak run capacitor cause a loss or torque? I recently bought a used wood shaper, it starts right up but stalls immediately when I put it under load. I can't say if it's running at full speed before this happens because I've never seen it run properly. I'm at my wits end and would greatly appreciate any help you can give me.
THANKS FOR YOUR TIME MATE
So, 350 Hz and I think this was a four pole motor? So that would be about 1750*6=10,000 RPM? It was interesting that the torque dropped so much that it stalled in the first test, then it held speed when wired for 240V. It should be possible to get at least 2x the rated HP by overclocking and keeping the V/F ratio. And you can usually overload an induction motor by 2x to 3x torque before breakdown and stall, so as much as 6x total HP. And maybe more with special windings.
You are AWESOME. Cool video.
You could do that, Set P1.10 to 25 Hz, then set P3.2 to 25 Hz. That would make the controller output full voltage at 25 Hz, and thus give the most possible current to the motor for the greatest torque, at half speed. Of course this assumes the overcurrent trip hasn't been set off. The only real problem is the motor would be overdriven technically, you would have to add an external fan, or you would destroy the motor.
I have a concrete block machine. It has a control panel set up for 40 amp, 220, 3ph. The machine has four motors rating from 2.2kw to 3 kw 1380rpm 50 hz.
Darren Dinsmore
Hi Darren - Make sure your Motor is set up for Delta windings( if it is a 220/440V motor.)
So if your goal is torque you should be wiring high voltage? I am wiring up motors to move an auger and it takes a lot of torque
That voltage probably will damage the motor, as it is likely beyond the windings' insulation rating. The number of poles in this case won't make much of a difference. A high speed motor, That is a motor which is rated for 10000 RPM would be more suitable, as it has bearings designed for high speed operation. It is likey that you can have the bearings changed for high speed, and you may be able to get the motor rewound for a lower voltage so you can achieve full speed with no torque loss
Is current independent of frequency and voltage or does the value of current remains constant with the change in frequency and voltage while operating induction motor with VFD? Because in my view current increases at low frequency and at low voltage to deliver same power. So this high current will eventually burn the insulation of the motor.
Nice video! I have a 220/380v oil filled drum motor wich i like to run on 3 hertz. does this kill my motor?
If the input voltage is 220 volts then the output voltage should be 220 volts at base frequency. Base frequency is the frequency at which the VFD will output maximum voltage, and it is programmable.
So you can run a 220 volt 50 Hz motor at 300 Hz and 220 volts, but as I explain in the video you will lose torque. You could however, use a 400- 480 volt VFD, program the base frequency to 120 Hz, then run your motor at 300 Hz and 480 volts.
I'm pretty sure a good run capacitor is needed for correct operation. I would try replacing it before you do anything else
Ok , thanks for your fast reply. I have another concrete question. I have VFD brand omron VS mini j7 his input is 220 volt I want to use motor for spindle on 8-10000 rpm, Im planing to buy motor 220/380 volt 50hz 2,2kw 2860rpm acording to you experience is it possible to get about 3.5 times more rpm and how much torgue will I loose from this motor??My opinion is that it should work on about 175hz and I thing that I wont loose any torque? what do you thing about that ?
Can you tell me what specific VFD you used? And some of the basic specs if possible? thanks.
HI!!!
I saw your video here and Im interested for use standard motor of 50 hz via VFD on 300 hz how much voltage is outgoing from VFD? input voltage is 220v how much is output voltage?? Sorry for my bad english Im writing from Macedonia :)
what happens to motor power if i reduce the frequency? will it stay as constant or it decreases? if it decreases, how should i keep it constant?
Thanks for the explanation
thank you very much
God bless you
does speed exceeds written on motor plate? tachometer
Can this be used continuously or will the motor overheat? (talking only about "standard" 50/60Hz motors)
Sir may I asked your opinion , I want to install a VFD on my drill press what can you recommend on how many HP should I get for a motor , is it better to get a 3 phase motor and how much HP should I get and what VFD brand you recommend on the motor that will work on the VFD your going to recommend , thank you sir for your opinion and keep up the good work and more power to your you tube channel!
It all really depends on the drill press in question. It would certainly be better if you could use a 3 phase motor instead of a single phase motor. I have a drill press myself that I believe has a 3/4 HP motor. But again, this all depends on how big your drill press is and what you intend to drill with it.
Great Vid!!! Thanks!!!
Can you plz tell me what is that material(name of metal) used as an electromagnet....
Watched it again and answered that
SIR WANT TO RUN 3 PHASE MOTOR AT 30 RPM WILL IT BE FEASIBLE .motor specs are 220-240 v delta connection. power 1.1 kw and 4.7 amps full load current
What is a short circuit motor?
Good day friend, I searching for answers and saw your video and I'm asking for some help. We are using a delta VFD-B to run a 25hp motor for a 250lbs washer extractor. I'm new to the whole thing so I set up some parameters to the best of my knowledge. The machine runs ok with just the basket and water but for some reason the motor won't spin when the machine is loaded with wash load. Can you help please?
Sure. So I take it this isn't a variable torque application, For example once loaded the load is fairly constant correct? If so, I would check the V/F Ratio. In other words, if the Motor wants to have 460 volts at 60 Hz, make sure the VFD is programmed to output that. If your V/F ratio is too low (for example, 240 volts at 60 Hz) it will stall the motor. Check that and let me know if you're still having problems. Thanks
Great video, I however can not seem to run my vfd without getting an over current fault. It trips off only a few seconds after start up. I have tried lengthening the start up and lowering the Hz. Any thoughts would be appreciated. Thanks
What is the nameplate FLA and voltage of your motor? What is the maxim current rating for your VFD?
Thank you for this video, it is useful information.
I am struggling trying to work out why I have little torque from a 50hz delta motor as in when connected to the VFD it spins as expected but can be stopped dead just by taking hold of the shaft with my hands.
I have 4 motors and 2 work fine and the other 2 I just cannot get any torque from them and I would really like to know why.
The VFD is 2.2kw 220v HuanYang VFD, it runs a 2.2kw spindle motor perfectly at 400rpm.
I also have a 2.2kw 3 phase motor that is 50hz, the plate says 220v delta or 440v star and works perfectly well at 50hz delta of the HuanYang VFD
I also have a 3/4hp 50hz Hoover motor that the plate says 220v delta or 440v star but when wired delta and ran at 50hz it is gutless and has very little torque and I do not understand why.
Finally I have a SEW Eurodrive motor that is about 1/4hp that the face plate says 440v star, the wiring block inside can be changed to delta (although the face plate does not give specs for delta) and this also has no torque when running at 50hz delta
The only difference I can see is that the 2 that work fine are rated at 2.2kw and the 2 that don’t run properly are smaller motors more like 1kw, but I cannot see why a 2.2kw VFD would not be capable of running a 1kw motor so I don’t think this is relevant.
I would really like to know what I am doing wrong if you have any input
Small induction motors have high resistance windings. The high resistance windings drop a lot of voltage and reduce the current down too low to produce much torque. Most likely you need to increase the output voltage. You can either change the V/F ratio or add torque boost. Some VFDs call this "IR compensation"
Hi.
Well, I am usign a motor that works at 60Hz and Im controlling it with the same VDF as you.
I want to know if I can run the motor whith a frecuency higher than 60Hz due ti the VDF can run at 400Hz.
Im not expert in the topic so I decided to reply you because at the momement just run the motor at 60Hz or less.
I hope you answer as fast as you can.
Hi Jay, Did you find out why the smaller motors produced so little torque when run off of a larger VSD?
I've had mixed fortunes running 3ph motors, in Delta, from budget cost Chinese single phase 240V in/240v out VSD's:
1) My old shaper machine with a 0.37kW 3ph motor ran fine, in Delta, on the default parameter settings of a cheap 0.75kW VSD .
2) But, a newer 0.55kW SEW motor, powered by the same 0.75kW VSD, produced almost no torque below 30Hz. I eventually bought a more expensive VSD and then the SEW motor worked OK.
3) I've also experienced a curious problem with a 0.18kW motor wired in delta, powered by the cheap 0.75kW VSD. It ran at 1/3 rated speed and became too hot to touch within less than a minute! The same motor ran fine on a real 3ph supply. Go figure!!
Regards Paul in NZ
Question:
What would you have to do for a motor to change its torque while mantaining constant its speed? And to change its speed while maintaining torque constant? As for example a vinyl turntable does
Variable frequency drives with torque control either read the motor speed directly with a tachometer (encoder,resolver or similar), or estimate using a motor model and by measuring the phase currents. From there, the vfd can adjust the torque to cause the motor to maintain constant speed even under varying load, this is done by adjusting the output voltage and frequency in realtime. A small computer inside the vfd calculates the difference between the commanded speed and actual speed and makes real time decisions as to what will best correct the error, but it's usually an adjustment to output voltage. Holding constant torque is similar but a little more complicated. The computer inside the VFD must again read a model of the motor but it must be a fairly accurate model of the motors flux torque relationship. From this, the computer can again make real time decisions as to what combination of voltage and frequency output will have the desired impact on the rotors flux. For example, a maximum torque command will cause the VFD to attempt to accelerate the motor as fast as possible, and this will cause the VFD to output maximum voltage, but the frequency will need to be determined from the motors actual shaft speed. (hence the tachometer). A half torque command probably wouldn't require the same output voltage, but would still need a good reading of the motor shaft speed.
So the thing that modifying frecuency, chances the spinning velocity of the inducted magnetic field whereas by modifying the voltage applied, you chance the inducted fields strength. Great data! Thank you for all the explanation!
it's not that motor does nothing at higher speeds it's because the rotation of rotor can't keep in sequence with the frequency of apply signal, thus rotor can't produce any rpm of rotation
i have a question can i use that speed controller to lower the speed of a motor that has 1700 rpm to 10 rpm? and keep using that 10 rpm for long periods of time?
Sure just put a separate cooling fan on the motor
Thanks allot
sir please upload the internal structure of physical VFD
can you use any 3 phase motor with a VFD?
Any 3 phase induction motor can be used with a VFD, as long as the VFD has the right output voltage and current capacity. Permanent magnet motors can be used but they usually require a encoder. Thanks for watching
Sir please I want high voltage igpt driver curcute please
Yeah mate about the IGBT for zvs driver. It's for arcs!! Not induction! Many thanx for ya time friend ;-)
what if we change the rotor of a induction motor (A.C) with permanent magnets... what will happen will it increase the torque and rpm or it will decrease?
Both will decrease as an A/C construction rely on both push and pull.
Not necessarily. RPM should increase as it would match the synchronous speed without any slipping. Torque should increase per amp since magnetizing current is no longer required by the PM rotor. As long as the magnets are strong enough to resist being demagnetizied by the stator
subcooledheatpump
Speed and torque would decrease exactly because a permanent magnet can not offer the same amount of push or pull. Introducing a permanent magnet is effectively to move the equilibrium to one side. That's why a DC design is about 10 - 15% less efficient when not taking this into consideration. A clever DC on the other hand is usually 10% more efficient than induction, but much more complex. Induction motors got complexity for free in the form of sinusoids.
en.wikipedia.org/wiki/Synchronous_motor#Permanent_magnet_motors
Why do you post that link? Did you understand what you read?
How much rpm would you say that it peaked at 220v?
Not sure in this video. But in a newer video I have made the motor hit 190 volts at 0 RPM
subcooledheatpump wut??? The max rpm bro
Ah sorry I thought you wanted to know at what RPM the voltage peaked. Peak RPM in this video was probably about 6000 RPM since it's a 6 pole motor
#EEE
vfd purpse 220v,440v
Motor fan could be blow off due to high RPM ...don't DO this with 50HZ motor
don't hold your sleeve close to the shaft. it might destroy your arm if it catches. very foolish what you did
vfd purpse 220v,440v