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  1. #1
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    Ebay 3 phase motor find

    Got this ordered, any clues on how this will perform on my RF-45?

    https://www.ebay.com/itm/165176176624

    I thought it was a deal for $119.00 and I got this VFD for it.

    https://www.ebay.com/itm/390919779712

    I know I should have gone with at least a Huan Yeng, but it should work. So the 3000 RPM should get me almost 4500 RPM at the nose, any clue how well the spindle will hold up at those speeds?
    Halfnutz

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  2. #2
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    Re: Ebay 3 phase motor find

    Hi,
    three phase motors that are made for running off a VFD are called 'inverter ready' and attract a significant premium.

    Most ordinary three phase motors work fine but the VFD introduces high frequency currents which result in very high (local) voltages within the windings
    which can result as a flash-over. Inverter ready motors often have vacuum impregnated windings and increased insulation thickness to accommodate those voltages.

    Most rotors will accommodate running a bit faster than rated speed, but you might be pushing the envelope at 4500 rpm, remember that the centrifugal forces go up
    as the square of speed so: (4500/2800)2=2.6 times the force.

    Craig

  3. #3
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Halfnutz View Post
    Got this ordered, any clues on how this will perform on my RF-45?

    https://www.ebay.com/itm/165176176624

    I thought it was a deal for $119.00 and I got this VFD for it.

    https://www.ebay.com/itm/390919779712

    I know I should have gone with at least a Huan Yeng, but it should work. So the 3000 RPM should get me almost 4500 RPM at the nose, any clue how well the spindle will hold up at those speeds?
    With a regular Ac 50Hz motor, 100Hz is the max you can run them at, to be safe, 80Hz would be the norm for that 50Hz motor. your VFD Drive should of had a larger capacity than the motor, the 3Kw VFD Drive would of been the best buy for Single Phase use.
    Mactec54

  4. #4
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    The supposed risk of using an ordinary 3ph motor is not so much the freq, all though this is important, the supposed risk is due to the nature of the high frequency pulses that the sine wave is made up from.
    Incidentally, over the years, all the VFD/Motor control I have implemented has been with old style, non (VFD) rated motors. To avoid any stress, I typically used 3ph suppression filter chokes in the motor phases.

    The oldest was on a 1958 CNC 25' bed mill rail planer retrofit, machine was circa 1958
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  5. #5
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    Re: Ebay 3 phase motor find

    Hi,
    I put a VFD on our small lathe at work....after a while the motor blew up.

    I got a cheap (Chinese or maybe Indian?) motor and it lasted a week. My boss was livid and wouldn't allow me to get another....he is such a cheapskate......so I fitted an old English made motor we had
    in the workshop which I think was originally in a bulk fuel pump. That was 17 years ago....the same motor is still running on the VFD. If someone told me this motor was made during WWII I would not be surprised.

    I came to the conclusion that the old motor was just well built with good insulation and that's why it lasted....cheap motors with poor insulation last hours at best.

    Craig

  6. #6
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    Could well have been a Brook motor, I grew up with those in the UK, one of the most popular brand to this day.
    It is wise to fit the output inductor when using non-VFD rated motors.
    Chinese motors have a very bad record for endurance.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  7. #7
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    Re: Ebay 3 phase motor find

    Hi,
    yes I think you may be right, I seem to recall Brook and Compton????

    I do definitely remember that it was totally enclosed cast iron and weighed a ton despite only being 3hp, and being totally enclosed with sealed input housing
    tallied with it being used a a fuel pump motor.....it may have come from a WWII era submarine resupply depot that was built in our harbour, although, thankfully was never
    used. My understanding was that quite a bit of equipment that was supposed to be returned to the Navy or wherever it came from, never quite made it back....locals
    purloined it an re-purposed it.

    Craig

  8. #8
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by joeavaerage View Post
    Hi,
    yes I think you may be right, I seem to recall Brook and Compton????
    Craig
    Right, They started out as Brook motors and shortly after became Brook Crompton after the union of the two companies.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  9. #9
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    Re: Ebay 3 phase motor find

    So, the VFD came in, fast, its about the size of a pack of cigarettes (not really), I'm going to use it on this little 400 watt 3 phase lathe I have and go ahead and order a 4 or 5 HP Huanyang. Crazy they can build, sell and ship a motor that size for $119. If anything it will last a little while. If it craps I have a 1.5 KW Marathon I'll replace it with. I am curious what the motor is going to be like....

    Ive had good luck with the chinese single phase motors, but I dont do any really hard work with anything anymore. Just getting out to the shop and turning everything on is difficult. I think I'm going to hire this little girl from the hood to help me out. If nothing else, It will make getting up and atem more fun.
    Halfnutz

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  10. #10
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Halfnutz View Post
    So, the VFD came in, fast, its about the size of a pack of cigarettes (not really), I'm going to use it on this little 400 watt 3 phase lathe I have and go ahead and order a 4 or 5 HP Huanyang. Crazy they can build, sell and ship a motor that size for $119. If anything it will last a little while. If it craps I have a 1.5 KW Marathon I'll replace it with. I am curious what the motor is going to be like....

    Ive had good luck with the chinese single phase motors, but I dont do any really hard work with anything anymore. Just getting out to the shop and turning everything on is difficult. I think I'm going to hire this little girl from the hood to help me out. If nothing else, It will make getting up and atem more fun.
    It will be fine as long as you don't go more then 100Hz with the VFD Drive Max speed settings
    Mactec54

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    Re: Ebay 3 phase motor find

    Quote Originally Posted by mactec54 View Post
    It will be fine as long as you don't go more then 100Hz with the VFD Drive Max speed settings
    You think it will be ok setting it up with the max hz at 100? And set the current to its rated max?

    What about the VFD, should I get a Huanyang or use this little one? It only has 34 parameters, not like the ones I'm use to.

    OK, so the old setup is 1970 Spindle RPM with a single phase rated at 1720RPM at 60Hz.

    The new one is 2800RPM at 50Hz., so even just giving it 75Hz should get me a spindle rpm of over 4000RPM. Is it safe to go any faster than that?

    Do you think its definately Chinese? It looks like it could be Turkish or Romanian or some other non EU country.
    Halfnutz

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  12. #12
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Halfnutz View Post
    S and go ahead and order a 4 or 5 HP Huanyang. Crazy they can build, sell and ship a motor that size for $119. .
    That is a 2pole 2800rpm 50Hz motor, 3000rpm rated, hopefully the bearings will stand up at 6000rpm.!
    I know of one importer of Chinese machines, the first thing he does is replace the motors!! :banana:
    CNC, Mechatronics Integration and Custom Machine Design

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  13. #13
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Halfnutz View Post
    You think it will be ok setting it up with the max hz at 100? And set the current to its rated max?

    What about the VFD, should I get a Huanyang or use this little one? It only has 34 parameters, not like the ones I'm use to.

    OK, so the old setup is 1970 Spindle RPM with a single phase rated at 1720RPM at 60Hz.

    The new one is 2800RPM at 50Hz., so even just giving it 75Hz should get me a spindle rpm of over 4000RPM. Is it safe to go any faster than that?

    Do you think its definately Chinese? It looks like it could be Turkish or Romanian or some other non EU country.
    Like I said in the first post 80Hz would be safe 100Hz max, the VFD Drive you have is worth a try, 34 Parameters you only need to add the motor name plate spec's for that motor which will be around 5 Parameters just leave the rest at default, just where the motor max Hz is set to 80Hz it will be by default at 50Hz or 60Hz
    Mactec54

  14. #14
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Al_The_Man View Post
    That is a 2pole 2800rpm 50Hz motor, 3000rpm rated, hopefully the bearings will stand up at 6000rpm.!
    I know of one importer of Chinese machines, the first thing he does is replace the motors!! :banana:
    Bearings of that size can run at 10,000 RPM Plus, the Bearings are never a factor, in any Ac 3 phase motor. Balance is the biggest problem in all AC 3 phase motors, the factory only Balance to just over it's rated max RPM, this only applies to regular 50Hz / 60Hz motors, as there are some AC 3Ph motors that are 6,000 RPM rated
    Mactec54

  15. #15
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by mactec54 View Post
    Bearings of that size can run at 10,000 RPM Plus, the Bearings are never a factor, in any Ac 3 phase motor. Balance is the biggest problem in all AC 3 phase motors, the factory only Balance to just over it's rated max RPM, this only applies to regular 50Hz / 60Hz motors, as there are some AC 3Ph motors that are 6,000 RPM rated
    Other opinions and experience may differ!
    From my experience with Chinese 1ph motors, if the 3ph are similar, I would be wary.
    The manuf. motor spec does state 3000 rpm rated as a clue.
    As far as I can see, there is no declaration that it is VFD rated??
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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  16. #16
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    Re: Ebay 3 phase motor find

    until I read this thread I have never heard of a VFD rated motor. But you do have to understand the difference between star and delta wiring. Our mains is 240v AC single phase or 415 v 3 phase.
    star gives 415v per phase, delta gives 240 v per phase (ideal for home use on single phase cos thats all you got coming in). In my case I have 3 phase and had a 415v 3 phase input VFD on hand. I've ordered an ordinary 3 phase motor for a machine I'm upgrading and will wire it star.

    I have no idea how you guys in the US do it but the 110v/220v mains sure complicates life! So a 110/240v single phase motor becomes 240/480V here with the latter being totally useless!
    Rod Webster
    www.vehiclemods.net.au

  17. #17
    Community Moderator Al_The_Man's Avatar
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by rodw View Post
    But you do have to understand the difference between star and delta wiring. Our mains is 240v AC single phase or 415 v 3 phase.
    star gives 415v per phase, delta gives 240 v per phase (ideal for home use on single phase cos thats all you got coming in). In my case I have 3 phase and had a 415v 3 phase input VFD on hand. I've ordered an ordinary 3 phase motor for a machine I'm upgrading and will wire it star.

    I have no idea how you guys in the US do it but the 110v/220v mains sure complicates life! So a 110/240v single phase motor becomes 240/480V here with the latter being totally useless!
    N.A. has not been 110/220 since then end of WW11!
    Now 120/240v is fairly standard all over.
    240v/480v star/delta motors are common here.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
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  18. #18
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    Re: Ebay 3 phase motor find

    Quote Originally Posted by rodw View Post
    until I read this thread I have never heard of a VFD rated motor. But you do have to understand the difference between star and delta wiring. Our mains is 240v AC single phase or 415 v 3 phase.
    star gives 415v per phase, delta gives 240 v per phase (ideal for home use on single phase cos thats all you got coming in). In my case I have 3 phase and had a 415v 3 phase input VFD on hand. I've ordered an ordinary 3 phase motor for a machine I'm upgrading and will wire it star.

    I have no idea how you guys in the US do it but the 110v/220v mains sure complicates life! So a 110/240v single phase motor becomes 240/480V here with the latter being totally useless!
    The US does not have 110v Ac power supply, it is 120v / 240v the same as what you have, except they can split the 240v and give them 120v / 240v for single phase so have a choice of using 120v or 240v.

    For anything related to using a VFD Drive unless using a small 3Ph motor, they would be using 240v single Phase in NA for the supply to the VFD Drive, if they did not have a 3 Phase supply.

    Quality Ac 3 phase motors that are Inverter Duty, use inverter-grade magnet wire in their windings, as well as spike-resistant insulation, which makes them better to use than a standard AC 3 phase motor. they come with a price tag as well, and also have rotor Grounding

    Inverter-Duty Motor Designs
    Most motor manufacturers offer general-purpose, three-phase premium efficiency motors that feature “inverter-friendly” insulation systems. These “inverter-ready” motors are suitable for use with variable torque loads over a wide speed range. In contrast, inverter-duty motors are wound with voltage spike-resistant insulation systems.
    Some use inverter-grade magnet wire to minimize the adverse effects of waveforms produced

    There is a lot of information on Inverter Duty motors, and what it means, if you need constant Torque or variable Torque, a regular AC 3 Phase motor is best suited in variable torque applications. so, if you want need constant Torque then you would want to use an Inverter Duty motor to suit.
    Attached Files Attached Files
    Mactec54

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    Re: Ebay 3 phase motor find

    Quote Originally Posted by Halfnutz View Post
    You think it will be ok setting it up with the max hz at 100? And set the current to its rated max?

    What about the VFD, should I get a Huanyang or use this little one? It only has 34 parameters, not like the ones I'm use to.

    OK, so the old setup is 1970 Spindle RPM with a single phase rated at 1720RPM at 60Hz.

    The new one is 2800RPM at 50Hz., so even just giving it 75Hz should get me a spindle rpm of over 4000RPM. Is it safe to go any faster than that?

    Do you think its definately Chinese? It looks like it could be Turkish or Romanian or some other non EU country.
    It does not matter where it was manufactured, if it does the job, you want it too.

    The main thing you have to watch for is motor Temperature, over heating will cause more problems than anything else.
    Mactec54

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    Re: Ebay 3 phase motor find

    The motor showed up yesterday, in a nice little chinese shipping box. It looks to be well made. Im in the middle of converting to cnc, and i figure now is the time to put it all together with a vfd controlled by Mach 3. Ive got so many projects going on right now, and I just work a little bit each day.
    Halfnutz

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

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