[janis93]

What is servo drive regenerative resistor?

When it is needed, and what it gives to my system?

Can I program this drive also via usb port, or I need the cable you pointed out?

[mactec54]

What is servo drive regenerative resistor?

When it is needed, and what it gives to my system?

Can I program this drive also via usb port, or I need the cable you pointed out?

I doubt that you would ever have a need for a braking ( regenerative ) resistor unless you have a mass that you are trying to stop in a hurry which could be the case when using high pitch Ballscrews

With quality servo drives the loop is closed in the servo drive, and can be corrected by the control if out of position, but not normally not needed to be controlled by the control for what you are building

Even with 3:1 the 400w servos will fail to perform with a 2020 Ballscrew even 750w would be at there max to run a 2020 Ballscrew so if you are looking for performance nothing less than 750w is going to do it for you

Most servo drives can be setup ( Programed ) by using a USB cable suited for the Servo Drive

How good are the Delta Servo system they are in the mid range in the market place, if you want a comparison Yaskawa is the number ( 1 )

[joeavaerage]

Hi,

Most servo drives can be setup ( Programed ) by using a USB cable suited for the Servo Drive

That is incorrect, the programming port on Delta servos is IEEE1394. In the marketplace there are two wiring standards for the
IEEE1394 plug, one of which can damage the drive. I elected to buy a genuine accessory. Note also that I chose the USB-IEEE1394
which is more expensive, a simpler RS232-IEEE1394 will cost as little as $20.

if you want a comparison Yaskawa is the number ( 1 )

Yep....real good....mind you they should be at 3-4 times the price.

Craig

[mactec54]

Hi,



That is incorrect, the programming port on Delta servos is IEEE1394. In the marketplace there are two wiring standards for the
IEEE1394 plug, one of which can damage the drive. I elected to buy a genuine accessory. Note also that I chose the USB-IEEE1394
which is more expensive, a simpler RS232-IEEE1394 will cost as little as $20.



Yep....real good....mind you they should be at 3-4 times the price.

Craig

Read what I posted, nothing incorrect about it you are confused again (nuts)

" What I posted " ( Most servo drives can be setup ( Programed ) by using a USB cable suited for the Servo Drive ) I did not say the Delta Drive could be but if you have the software you can use a converter USB to RS 232 is a common way most manufacturers do it

[joeavaerage]

Hi Matec,
tough!

Craig

[mactec54]

Hi Matec,
tough!

Craig

Tough! for you maybe with your pretending (wedge)

[NordicCnc]

I doubt that you would ever have a need for a braking ( regenerative ) resistor unless you have a mass that you are trying to stop in a hurry which could be the case when using high pitch Ballscrews

With quality servo drives the loop is closed in the servo drive, and can be corrected by the control if out of position, but not normally not needed to be controlled by the control for what you are building

Even with 3:1 the 400w servos will fail to perform with a 2020 Ballscrew even 750w would be at there max to run a 2020 Ballscrew so if you are looking for performance nothing less than 750w is going to do it for you

Most servo drives can be setup ( Programed ) by using a USB cable suited for the Servo Drive

How good are the Delta Servo system they are in the mid range in the market place, if you want a comparison Yaskawa is the number ( 1 )

Hi.

About the servo performance, I am building a machine with a Z-axis weight of 30kg, an X-axis weight of 60kg and gantry weight of approximately 100kg (including X and Z-axis).

I will be running 1605 ballscrew on the Z-axis, 2:1 with a braked servo. The X-axis will be run with 2020 and 2:1. The Y-axis will be dual motor and dual 2020 screws with 2:1 ratio.

But as you mentioned here that even 3:1 ratio with a 750W servo would be the bare minimum, I am having second thoughts about my desing. Originally I was planning 2010 screws on X and Y, with 400w servos and 2:1, but now I want more speed.

Don't you think that this would work well:

- 750W (maybe even 400W?) with 2:1 with 1605 for 30kg Z-axis
- 750W with 2:1 for 60kg with 2020
- 2x750W with 2:1 with 2x2020

Here is my build log if you are interested: https://r.tapatalk.com/shareLink/top...ink_source=app

Skickat från min SM-A530F via Tapatalk

[joeavaerage]

Hi,
my new build mill has axis beds of 75kg. Thus I would expect the Y axis partiularly to be required to accelerate the X axis bed, linear rails,
ballscrew and servo, vice and workpiece AND control cutting forces. I anticipate the mass alone will be about 110kg. I am planning
direct coupling the servo to the 32mm diameter 5mm pitch screw.

I am of the opinion, and have calculations to support it, that it will work. The ratio of the moments of inertia between the servo armature and the ballscrew
and attached beds/mass suggest that I may have some fun trying to tune the combination. A medium inertia servo would be better in this regard.

Follow this calculation:

750W servo, rated continuous torque =2.4Nm
Effective radius of a 32mm ballscrew= 16mm =0.016m
[email protected]=2.4/0.016
=150N

Mechanical advantage of a 32mm diameter screw or 5mm pitch is:
mechanical advantage=32 x pi / 5
=20

Thrust ( at rated torque)= 20 x 150
=3kN

Lets say that half of that thrust is available to accelerate the axis and the remainder overcomes friction and controls cutting forces:
Accelerating thrust= 3kN x 0.5
=1.5kN
F=M x A or A=F /M
acceleration =1500/110
=13.6 m/s²

The acceleration of my 110kg axis could be as high as 1.3g.....and thats only rated torque, if I allow axis tuning to use the the overlaod torque
I could accelerate at close to 4g!!!, and that still assumes ONLY ONE HALF of the torque is available for axis movement. More likely
3/4 to 7/8 in actual practice.

In short a 750W direct coupled servo is way more power than I can really use, 400W would still be more than adequate, but 750W servos
were only another $30 each so I got them.

I can have G1's of 15m/min (3000 rpm) and G0's of 25m/min (5000rpm).

Yes you can get your 3000rpm Delta servo to do 5000 rpm, using a feature called feild weakening. It loses some of it top end
torque, but hey I've got swags to spare!

I think you'll have more power and speed that you can possibly believe with the servos you have listed.

Craig

[NordicCnc]

Hi,
my new build mill has axis beds of 75kg. Thus I would expect the Y axis partiularly to be required to accelerate the X axis bed, linear rails,
ballscrew and servo, vice and workpiece AND control cutting forces. I anticipate the mass alone will be about 110kg. I am planning
direct coupling the servo to the 32mm diameter 5mm pitch screw.

I am of the opinion, and have calculations to support it, that it will work. The ratio of the moments of inertia between the servo armature and the ballscrew
and attached beds/mass suggest that I may have some fun trying to tune the combination. A medium inertia servo would be better in this regard.

Follow this calculation:

750W servo, rated continuous torque =2.4Nm
Effective radius of a 32mm ballscrew= 16mm =0.016m
[email protected]=2.4/0.016
=150N

Mechanical advantage of a 32mm diameter screw or 5mm pitch is:
mechanical advantage=32 x pi / 5
=20

Thrust ( at rated torque)= 20 x 150
=3kN

Lets say that half of that thrust is available to accelerate the axis and the remainder overcomes friction and controls cutting forces:
Accelerating thrust= 3kN x 0.5
=1.5kN
F=M x A or A=F /M
acceleration =1500/110
=13.6 m/s²

The acceleration of my 110kg axis could be as high as 1.3g.....and thats only rated torque, if I allow axis tuning to use the the overlaod torque
I could accelerate at close to 4g!!!, and that still assumes ONLY ONE HALF of the torque is available for axis movement. More likely
3/4 to 7/8 in actual practice.

In short a 750W direct coupled servo is way more power than I can really use, 400W would still be more than adequate, but 750W servos
were only another $30 each so I got them.

I can have G1's of 15m/min (3000 rpm) and G0's of 25m/min (5000rpm).

Yes you can get your 3000rpm Delta servo to do 5000 rpm, using a feature called feild weakening. It loses some of it top end
torque, but hey I've got swags to spare!

I think you'll have more power and speed that you can possibly believe with the servos you have listed.

Craig

Thanks for the thorough explanation. I was asking because mactec54 claimed the power being way too low. I am not saying that he is wrong but according to the calculations, even 400w would be sufficient!

Skickat från min SM-A530F via Tapatalk

[NordicCnc]

Here are the calculations done with Sigma Select (Sigma software for calculating Yaskawa servo sizes).

According to the reports when using 400W servos (see attachments), peak toque would be at the rated torque on the X-axis (0,1s acceleration, 30m/s, 2010 screw, 2:1 ratio) and a little bit over on the Z-axis (0,1s acceleration, 7,5m/s, 1605 screw, 2:1 ratio). The Y-axis I am pretty confident that will be fine with 2x 400W motors.

[joeavaerage]

Hi,
another way of looking at it is to use 750W, being approx double the torque of 400W units and drop the 2:1 belt reduction.

Cant say about Yaskawa but 750W Deltas are only about $30 more than 400W ones. I bet the belt and pulleys cost more than $30.

Craig