[mcphill]

I have a Marathon BlackMAX inverter duty motor. It is 4-pole, will be run at 220 VAC, and has a baseplate RPM of 1800. https://www.automationdirect.com/adc...duty/y551-a772

I will be running it with this VFD: https://www.automationdirect.com/adc...vfds/gs21-23p0
The VFD is capable of outputting 400 hz.

So the question is, how fast can I safely run this motor? I am hoping to be able to run it at 5000 rpm. If I can't, where can I find a 2-3 hp motor that can be run that fast?

[Al_The_Man]

I think you may just make it with that motor, if you want to confirm maybe, try an email to support https://www.regalrexnord.com/brands/...ter-Duty-Motor

[mcphill]

e-mailed, guess we'll see if I get a response. Would the only "harm" be vibration/mechanical instability if I go "too far"? I mean sure it will eventually rip itself apart, but again, that's a "mechanical issue" - is there any electrical risk in running at too high a frequency?

[mactec54]

I have a Marathon BlackMAX inverter duty motor. It is 4-pole, will be run at 220 VAC, and has a baseplate RPM of 1800. https://www.automationdirect.com/adc...duty/y551-a772

I will be running it with this VFD: https://www.automationdirect.com/adc...vfds/gs21-23p0
The VFD is capable of outputting 400 hz.

So the question is, how fast can I safely run this motor? I am hoping to be able to run it at 5000 rpm. If I can't, where can I find a 2-3 hp motor that can be run that fast?

It may be able to as it is a closed loop vector motor, look for a washdown motors they normally can run at those high RPM, you don't need this type of motor unless you need to control the speed, very precisely, a regular vector duty motor without an encoder will work for most applications.

Most VFD Drive can do 400Hz =12,000 RPM for a 4p motor 24,000RPM for a 2p motor, so you won't be needing 400Hz for this type of motor.

[mactec54]

e-mailed, guess we'll see if I get a response. Would the only "harm" be vibration/mechanical instability if I go "too far"? I mean sure it will eventually rip itself apart, but again, that's a "mechanical issue" - is there any electrical risk in running at too high a frequency?

Yes, if it is not designed to use High Frequency it will burn up quite quickly if incorrectly Hz is used. so, if it is a 60hz rated motor normally 120Hz is the max, being a Vector Duty Motor, it would be able to go to its max rating RPM, so to run at 5000RPM you would be using a max of 166Hz for a 4pole motor you may need 167Hz or 168Hz to get the exact 5000RPM.

[Jim Dawson]

According to the spec pdf, 5400 RPM max

https://cdn.automationdirect.com/sta...rsblackmax.pdf

[Al_The_Man]

According to the spec pdf, 5400 RPM max

So 180 Hz, or slightly above to allow for slip.

[servtech]

According to the spec pdf, 5400 RPM max

https://cdn.automationdirect.com/sta...rsblackmax.pdf

To me the overriding factor would be if the bearings and motor can dissipate the heat without melting the winding insulation or the bearings.

Running up to 5000rpm when required within the duty cycle of motor and drive is probably ok, but running continuously at these speeds could fry one, other or both.

[Al_The_Man]

To me the overriding factor would be if the bearings and motor can dissipate the heat without melting the winding insulation or the bearings.

Running up to 5000rpm when required within the duty cycle of motor and drive is probably ok, but running continuously at these speeds could fry one, other or both.

Marathon motors are quite a reputable make, I don't see them introducing misleading specs!?

[servtech]

Marathon motors are quite a reputable make, I don't see them introducing misleading specs!?

With respect, no spindle or spindle motor will have longevity running continuously flat out under load. Over the years I have changed umpteen spindles and motors for this very reason. Siemens, Fanuc, Yaskawa and so on.

A Porsche might be able to reach 100mph in first gear, but not for long if you keep it there.

Motor and drive duty cycle are all important. How many accelerations and decelerations per hour needs to be determined.

[Al_The_Man]

I didn't see anyone specify that the spindle may be running flat out continuously, it just seemed the OP was curious as to the max motor RPM?.

[mcphill]

According to the spec pdf, 5400 RPM max

https://cdn.automationdirect.com/sta...rsblackmax.pdf

Thanks for finding that, Jim. I have probably looked at that PDF but missed that detail. That said, it indicates max 5400 rpm when running 460 volts. Any difference at 220 volts (just double the current?)?

[mactec54]

Thanks for finding that, Jim. I have probably looked at that PDF but missed that detail. That said, it indicates max 5400 rpm when running 460 volts. Any difference at 220 volts (just double the current?)?

Yes, I would have posted the same PDF, but this is not for your motor specs, the 460v motor has completely different motor windings, not saying that your 220v / 240v motor won't have similar specs! inverter duty kind of say it is and will do what you want, but get the correct specs.

[mactec54]

So 180 Hz, or slightly above to allow for slip.

You don't need to allow for slip most VFD Drives can compensate for slip if the Parameters get set, a VFD Drive used in Vector mode can Auto-tune for slip.

[mactec54]

With respect, no spindle or spindle motor will have longevity running continuously flat out under load. Over the years I have changed umpteen spindles and motors for this very reason. Siemens, Fanuc, Yaskawa and so on.

A Porsche might be able to reach 100mph in first gear, but not for long if you keep it there.

Motor and drive duty cycle are all important. How many accelerations and decelerations per hour needs to be determined.

You are talking about your experience with machining centers where spindle mostly fail from abuse, 5,000 RPM is very slow compared to 24,000RPM or a 60,000 RPM spindle which most hobby users are running, some are getting many years of use before new Bearings are needed, and they leave their spindle running over night sometimes 24 hours or more, of run time can be normal for some of these 24,000 RPM spindles, they last very well, if setup correctly.

So, 5,000 RPM is nothing for a Vector inverter duty Motor like this.

[Jim Dawson]

Thanks for finding that, Jim. I have probably looked at that PDF but missed that detail. That said, it indicates max 5400 rpm when running 460 volts. Any difference at 220 volts (just double the current?)?

That's 230/460 dual voltage motor. Pretty sure the performance is the same for both voltages.

[deadlykitten]

VFD : very afordable spindles

push it to max

[servtech]

You are talking about your experience with machining centers where spindle mostly fail from abuse, 5,000 RPM is very slow compared to 24,000RPM or a 60,000 RPM spindle which most hobby users are running, some are getting many years of use before new Bearings are needed, and they leave their spindle running over night sometimes 24 hours or more, of run time can be normal for some of these 24,000 RPM spindles, they last very well, if setup correctly.

So, 5,000 RPM is nothing for a Vector inverter duty Motor like this.

Indeed, but price is reflected by the quality of the bearings and motor windings.
Cheap price means cheap components ????

[mactec54]

Indeed, but price is reflected by the quality of the bearings and motor windings.
Cheap price means cheap components ????

The motor the OP selected are the most expensive Ac motors, does not mean they are the best choice for the job.

The cheap Hobby Spindles that in general run at 24,000 RPM can last for years, and when I say cheap $98 to $400 can buy them a reliable spindle, the one below can be had for $245 and is one of the best to buy, it is water cooled.

[mcphill]

Yes, I would have posted the same PDF, but this is not for your motor specs, the 460v motor has completely different motor windings, not saying that your 220v / 240v motor won't have similar specs! inverter duty kind of say it is and will do what you want, but get the correct specs.

Same motor can be wired for low or high voltage, so that line is for the same motor. Not sure why they don't post the same chart for 220 V.