[ihavenofish]

ihavenofish
Quote es, all lies!
i know a couple of xzero demons have the 1000rpm models installed already, should be a video of it running somewhere if im not mistaken.

It is quite obvious you have no clue what you are talking about as usual,

You said it is the wrong servo motors, then at the end of your post say there are some xzero demons with the 1000rpm motors

That is what he is looking at & going to use for his demon machine, just the same as what is being used already

um. no, i said there are some people running these 1000rpm 300w motors. i also said they are overkill, and the smaller 400w 3000rpm motors will be more than adequate direct drive unless you use a big spindle.

you said you could not go with a smaller motor, and this is plain false, cause ive done it.

now without resorting to personal insults, whats not to understand?

[mactec54]

ihavenofish
Quote
you said you could not go with a smaller motor, and this is plain false, cause ive done it.

We have all seen what you have done, That also is not what I said, So get it right

For a starter DMM does not have a 300w motor that is a 1000rpm
The 300W motor spec is 48V, Max 3000rpm, rated torque:1.14Nm(160 oz-in),

As you can see the 300W motor with 160 oz-in Rated Torque, would not be enough for a 25mm pitch ballscrew on this machine

So what I said is correct
The motors are the right ones for a ballscrew of 25x25, so you are on the right track there, You could not go with a smaller motor unless you geared it down

Note what I said, You could not go with a smaller motor unless you geared it down

2.1 is all that is needed if someone wanted to go with a smaller motor

[ihavenofish]

$328 kit, 2.9nm, 1080rpm. thats the big motor right? thats 300w assuming the torque is flat.

thats the motor im talking about, that is the one that has been put on xzero demons with 2525 screws. its overkill on torque, but has a good speed range. overkill isnt a bad thing in this case. there is a limit to useful torque on a machine like the demon though, its only aluminium after all.

$280 kit, the one on the dmm page listed with 1.27nm continuous torque at 3000rpm, thats 400w assuming the torque is flat. this motor in DIRECT drive is good for the demon or raptor with 2525 screw, unless you go with a very powerful spindle. (most people wont). you will waste alot of the speed though, topping out in the 1500rpm range on the machine simply due to the screw length/balance.

now relax, you dont want to lose customers by being a hothead

[mactec54]

ihavenofish
Quote now relax, you dont want to lose customers by being a hothead
es, all lies! plain false, cause ive done it.

What ever I have said in these posts is a reaction to what ever you have written & there is nothing hothead about it

I'm not sure what you mean, lose customers, I only help people who buy the DMM system
get there system up & running, I'm not an employee of DMM

I have installed a lot of the Dmm systems, & others as well, so I know what works best for there system,The information I give is from doing installations & not just from testing there system

The motor you are talking about is the motor that azam1959 had already selected
They are not a 300W motor

At 48V 1050rpm at 60V 1350rpm, at 110/220V it will do 5,000rpm The motor you are talking about is a 750W AC servo motor derated only by the input Voltage

The 400W motor is not suitable for a direct drive to a 25mm Pitch Ballscrew, will it drive a 25x25 Ball screw Yes It Will, So will 100W motor drive a 25mm Pitch Ballscrew

The problem is 400W will drive it but what happens when you need to use a .500 cutter or bigger, Do you really think rated torque: 1.27Nm(179 oz-in) is going to cut it being direct drive, It is Not, most people with routers want to cut what they are making, not scratch at it for hours

If you use 25x10mm pitch Ballscrew then the 400W motors will work very well & in there power range

[ihavenofish]

in the supplied kit at 48v, its 300w. its pretty irrelevant at higher speeds in this specific case, you cant spin the screw much higher than 1000rpm anyway.

as for 1.27nm continuous, yes, its quite adequate actually on the 2525 with a gantry load of about 100-120lbs. using 3hp colombo spindle with 1.2nm torque will give a maximum of 190N or 42lbs of force on a 1/2" cutter. bigger cutters will exert LESS force on the axes at the same spindle torque. a 1/4" tool would exert 84lbs, but its likely to break with that kind of force. for reference, that cut is 1/2" width, 1/2" depth, 620ipm in the hardest wood you can find (none of this butter soft rock maple). thats not a cut most people would expect to run on a light machine like this.

on the motor, that translates to a mere 0.8NM

the screw itself has about 0.3nm drag

that leaves plenty of torque to overcome screw inertia and still acelerate at up to 0.15G, without moving into the intermittent torque zone.



edit: big math error, ahhh!. point still stands though

[mactec54]

ihavenofish

How do you figure out that the motor kit we are talking about is 300W at 2.9nm

When the 300W motor that Dmm does have in there other kit is only1.14nm 160ozs

So were do you get this number of 300Watts from

[ihavenofish]

ihavenofish

How do you figure out that the motor kit we are talking about is 300W at 2.9nm

When the 300W motor that Dmm does have in there other kit is only1.14nm 160ozs

So were do you get this number of 300Watts from

uh. 2.9nm at 1000rpm = 300w.

1080rpm would be 330w, but the drawing shows the torque drop off shortly after 1000, not sure if it makes it all the way to 1080 at full torque.

[mactec54]

ihavenofish

A different way to look at it, but not correct

48V x 8amp=384W this is the minimum it could ever be at 48V

The motor runs close to 10amps when running which makes that 480W so the kit as you get it is 48V 480W with a max of 20amp 960W output

The 60V option 60 x 8=480W at 10a running 600w with a max of 20amp 1200W output

[ihavenofish]

ihavenofish

A different way to look at it, but not correct

48V x 8amp=384W this is the minimum it could ever be at 48V

The motor runs close to 10amps when running which makes that 480W so the kit as you get it is 48V 480W with a max of 20amp 960W output

The 60V option 60 x 8=480W at 10a running 600w with a max of 20amp 1200W output

wow, no. power draw isnt a helpful piece of information, well, unless you need to run it on batteries

power output is 300w at 1000rpm, which is what the kit on the site lists. at 60v youd need to provide another torque curve (although its most likely still flat to 1300rpm-ish.

peak torque/power isnt useful to mention either unless its qualified with a duty cycle. i have parker motors that claim 300 oz in peak, but its a rating of 6 seconds with a cool down to 60C (half load for several minutes in ambient air) rendering it mostly useless on a mill axis.

anyhow, this is not the point of my comments. my comments were that the "big" motor is overkill unless you have a big spindle, and the "little" 1.27nm motors are quite adequate with the 2525 screw with the smaller spindles that most people run on these machines. and if you want to run a 10hp spindle on the demon, you may have a little more to worry about than the servo motor rating

[mactec54]

ihavenofish
Quote
power output is 300w at 1000rpm
wow, no. power draw isnt a helpful piece of information, well, unless you need to run it on batteries

It is very clear what the power draw is, Batteries or not

Very basic skills will tell you that the motor could never have a 300Watt rating, that you keep on saying the motor is

The power draw is around 10Amps (Plus) when it is running normal, This depends on what it is driving

The power draw at 1080 rpm 10amps= 480watts & is closer to 500watts because most I have tested have run at 10.4amps to 10.9amps when running normal, with machine drag these numbers will change to the machine condition or what the motor is driving

At idle holding power is 2.9nm at 8amps= 380watt Being supplied with 48V

The max power for this motor is 20amps=960watts 7.2nm Being supplied with 48V

[ihavenofish]

power = torque x speed / 9.5488
2.9nm x 1000rpm / 9.5488 = 303.7w


this isnt an argument, its fact. your dont rate a motor on power draw, you rate it on output at the shaft. thats the only useful number.

so, with the 48v kit, you have a 300w motor.

its a nice cheap powerful servo, why try to mislead?

[mactec54]

ihavenofish

its a nice cheap powerful servo, why try to mislead?

No body is missleading anybody,

Volts X Amps = Watts so what ever the Amps are when the motor is running that will be what the Watts are of the motor

[azam1959]

ihavenofish and mactec54,

I do remember your discussion on XZero site few months ago and reading posts here with lot of interest (thanks). I did my engineering in 70s and forgot most of the technical stuff which I do not use on day to day basis.

I am getting four 900W motors, controllers are upgraded for 75v so is the power supply (there will be three power supply in the control box). I made the deal with the vendor and I will pay them in Jan when I have funds.

I am OK with over power, who knows if XZero is as good as folks are saying, I may upgrade my 3hp spindle and inverter/vfd in future but for now .... if over power means damaging the machine, I will have to reconsider my decision and talk to vendor again.

Please help me make the right decision. Will these motors damage any of the screws in x,y or z direction?

ihavenofish

its a nice cheap powerful servo, why try to mislead?

No body is missleading anybody,

Volts X Amps = Watts so what ever the Amps are when the motor is running that will be what the Watts are of the motor

[ihavenofish]

I am OK with over power, who knows if XZero is as good as folks are saying, I may upgrade my 3hp spindle and inverter/vfd in future but for now .... if over power means damaging the machine, I will have to reconsider my decision and talk to vendor again.

Please help me make the right decision. Will these motors damage any of the screws in x,y or z direction?

they should be fine on the X, if a little ovekill. the 2525 screw can handle 19000N force, the support bearing handles 9000N, the servo puts out at peak only 2000n. the frame can take the force just fine. so the motor is overkill, but wont damage anything.


on the y, with a 2010 screw, you can deal with 15000N, the support bearing only 4500N, and the motor can push 5000n peak. 5000n is 1000lbs, which gets into teritory that could cause harm to the machine as well as the bearing. so its not only overkill, but potentially bad.

on the Z you have a 1605 screw. this screw can handle about 10000N, the support bearing 4500N, and the motor at peak will push with 10000N. this is a recipe for disaster.

NOW... keep in mind this force wont come into play in cutting or acceleration, its just not needed. it WILL come into play if you crash the machine.

so, id recomenend the big 2.9nm one on the X, and 2 of the 1.27nm ones on the y and Z.

[mactec54]

ihavenofish

Before you start giving people information you need to first buy a system & run it to see what it will do or won't do

The information that you have been putting in these posts is not CORRECT

I just called DMM & spoke with Hui the Owner Designer & Builder of there servo system

The motor that you keep saying is 300watts is Rated when on 48V at just over 500Watts just as I have been saying

So Please get your information correct before posting, So others users are not confused
as to what is correct

Build a machine your self & then tell everyone your experience with there system, you have no credibilty at this point untill you have use there system in all the situations you are talking about

[hub]

I have tested a 400W DMM servo & drive. Not much problems. Works pretty fine. I wish it had auto tuning etc etc.. But for the price, it performs well.

Reading all this... I don't see what RPM has to do with it. My DMM drive is rated max 60V DC I think. Using 48V @ max 400W is 8.3A. RPM does not change that.

[Al_The_Man]

Reading all this... I don't see what RPM has to do with it.

Read answer from Ihavenofish.

power = torque x speed / 9.5488
2.9nm x 1000rpm / 9.5488 = 303.7w

Al.

[hub]

Read answer from Ihavenofish.



Al.

Thanks
But currently that doesn't make sense. Unless you want to have constant torque independent of RPM. ?

[ihavenofish]

Thanks
But currently that doesn't make sense. Unless you want to have constant torque independent of RPM. ?

torque in most AC servos is constant or near constant to the rated rpm (in this case 1080 on 48v). at 100rpm is 30w. at 2000rpm it would be 600w. at 500rpm it would be 150w.

marketing cant change the laws of physics.

recomendations for this specific machine (which i have assembled and run several of) are based on experiece and math. the big -300- watt motor it too much for the y and z, and overkill on the x.

you can claim whatever you like about the motors and manipulate the numbers to sound sexy, you cant change reality.

this was never meant to be a pissing match. the motors are nice. they ARE 300w at 1000rpm, and they ARE overkill for the 2525 screw on machine being asked about.

people on this forum have a great tendency to use motors far more than the machine can handle. the idea that more is better is perpetuated by alot of manufacturers by listing useless numbers like peak torque or power. BETTER is better, MORE will often just break your machine.

[mactec54]

ihavenofish
you can claim whatever you like about the motors and manipulate the numbers to sound sexy, you cant change reality.


Your caluations are not in question

This only tells you how many Watts are Needed at 2.9nm x 1000rpm=303.7W This would be With No Load just sitting on the bench for this motor & not connected to anything

It does not tell you the motor rated watts, with this caluation, This is the part that you don't have correct