Re: [Emc-users] Servo Motor Retrofit sizing
On 04/04/2017 08:57 PM, Dave Cole wrote: > Here is a discussion about inertial mismatch. > > http://www.motioncontrolonline.org/content-detail.cfm/Motion-Control-Technical-Features/Understanding-the-Mysteries-of-Inertia-Mismatch/content_id/404 > > The Sizing software that Automation Direct has on their website can be > used to check motor sizing for non-Automation Direct motors. > > I have used it for years and it has never missed. > > Run the calculations and see how well they matched your original motors. > That will give you an idea if you can get by with 1/2 of the original > motor inertia. > > The only time you really have to be concerned about inertia matching is in cases where the bandwidth of the servo loop is capable of exciting resonances in coupling between the motor and the table. This could be a REAL issue in a system coupled with a timing belt driving the table directly. It is probably a lot less of an issue in leadscrew systems, although there can be torsional resonances in the leadscrew. Jon -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servo Motor Retrofit sizing
On 04/04/2017 01:35 PM, robert - Innovative-RC wrote: > Hi > > i am planning to retrofit a machine i will change the servo motors as > current ones are faulty etc > anyways i know the motor ratings on the machine right now as follows > > Yaskawa USAFED-30FS20E > Rated 18.6Nm > Continuou Max 22.5Nm > Peak max 54.1Nm > Rated Speed 1500rpm > Max Speed 2000rpm > Torque Constant 0.98Nm/A > Moment of Inertia jm(=GD2/4) 110.0kg.m2x10-4 > Power 2.9Kw > > now the servo i was looking at replacing with has the same torques but a > lower Inertia Jm value. Somewhat lower inertia should be no problem. > what effects does this have on the > accell/deaccel , i know motor it self takes less toque to accel its > self.. but how does this related back to the load wanting to carry on > moving when trying to deaccel it, what are the the realworld or other > impacts on the motor/drive , am i more likly to see higher bus > voltage/regen problems from the motor loading, as this motor is on a Z > axis and has no counter balance so the motor is braked for parking... > motor runs at 1500rpm, screw is 10mm pitch i am not looking to go any > faster just keep things the same ratings etc I would not worry about it except in VERY dynamic systems like routers moving over several meters/second. Probably any motor with this peak torque or more will be fine, and no need for more, 54Nm is plenty. Jon -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Servo Motor Retrofit sizing
Here is a discussion about inertial mismatch. http://www.motioncontrolonline.org/content-detail.cfm/Motion-Control-Technical-Features/Understanding-the-Mysteries-of-Inertia-Mismatch/content_id/404 The Sizing software that Automation Direct has on their website can be used to check motor sizing for non-Automation Direct motors. I have used it for years and it has never missed. Run the calculations and see how well they matched your original motors. That will give you an idea if you can get by with 1/2 of the original motor inertia. Dave On 4/4/2017 2:35 PM, robert - Innovative-RC wrote: > Hi > > i am planning to retrofit a machine i will change the servo motors as > current ones are faulty etc > anyways i know the motor ratings on the machine right now as follows > > Yaskawa USAFED-30FS20E > Rated 18.6Nm > Continuou Max 22.5Nm > Peak max 54.1Nm > Rated Speed 1500rpm > Max Speed 2000rpm > Torque Constant 0.98Nm/A > Moment of Inertia jm(=GD2/4) 110.0kg.m2x10-4 > Power 2.9Kw > > now the servo i was looking at replacing with has the same torques but a > lower Inertia Jm value. what effects does this have on the > accell/deaccel , i know motor it self takes less toque to accel its > self.. but how does this related back to the load wanting to carry on > moving when trying to deaccel it, what are the the realworld or other > impacts on the motor/drive , am i more likly to see higher bus > voltage/regen problems from the motor loading, as this motor is on a Z > axis and has no counter balance so the motor is braked for parking... > motor runs at 1500rpm, screw is 10mm pitch i am not looking to go any > faster just keep things the same ratings etc > > motor i was looking at replacing with is, as torque match's, > Rated 19.1Nm > Peak 57.3Nm > Rated Speed 1000rpm > max speed 1500rpm > Rotor Moment of Inertia 53.5kg.m2x10-4 > Power 2.0Kw > > or i go the next motor up > Rated 28.7Nm > Peak 86.0Nm > Rated Speed 1000rpm > max speed 1500rpm > Rotor Moment of Inertia 77.8kg.m2x10-4 > Power 3.0Kw > > maybe someone here can add some insight into what to watch out for when > resizing/replacing servos in CNC systems etc > > just when you look up about servo sizing alot talk about the inertia > ratio etc.. > > thanks, Rob > > > -- > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Servo Motor Retrofit sizing
Hi i am planning to retrofit a machine i will change the servo motors as current ones are faulty etc anyways i know the motor ratings on the machine right now as follows Yaskawa USAFED-30FS20E Rated 18.6Nm Continuou Max 22.5Nm Peak max 54.1Nm Rated Speed 1500rpm Max Speed 2000rpm Torque Constant 0.98Nm/A Moment of Inertia jm(=GD2/4) 110.0kg.m2x10-4 Power 2.9Kw now the servo i was looking at replacing with has the same torques but a lower Inertia Jm value. what effects does this have on the accell/deaccel , i know motor it self takes less toque to accel its self.. but how does this related back to the load wanting to carry on moving when trying to deaccel it, what are the the realworld or other impacts on the motor/drive , am i more likly to see higher bus voltage/regen problems from the motor loading, as this motor is on a Z axis and has no counter balance so the motor is braked for parking... motor runs at 1500rpm, screw is 10mm pitch i am not looking to go any faster just keep things the same ratings etc motor i was looking at replacing with is, as torque match's, Rated 19.1Nm Peak 57.3Nm Rated Speed 1000rpm max speed 1500rpm Rotor Moment of Inertia 53.5kg.m2x10-4 Power 2.0Kw or i go the next motor up Rated 28.7Nm Peak 86.0Nm Rated Speed 1000rpm max speed 1500rpm Rotor Moment of Inertia 77.8kg.m2x10-4 Power 3.0Kw maybe someone here can add some insight into what to watch out for when resizing/replacing servos in CNC systems etc just when you look up about servo sizing alot talk about the inertia ratio etc.. thanks, Rob -- Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
