## DG Rotary Hollow Actuator Specifications

om_tech_support_JT
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### DG Rotary Hollow Actuator Specifications

Q: What is the difference between Repetitive Positioning Accuracy, Lost Motion, and Angular Transmission Error in the specifications for your DG series rotary hollow actuator systems?

A:
Repetitive Positioning Accuracy is the degree of error that generates when positioning is performed repeatedly to the same position in the same direction.

Lost Motion is the difference in stopped angles achieved when the output table is positioned to the same position in bidirectional operation.

Angular Transmission Error is the difference between the theoretical rotation angle of the output table (as calculated from the input pulse number), and the actual rotation angle. This would be the maximum degree of error you could possibly encounter when positioning your output table to any position(when operating within specifications).

pichate
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Joined: Fri Nov 04, 2011 11:46 pm

### Re: DG Rotary Hollow Actuator Specifications

DG have have equation for calculation or not? purpose for how select model of DG.
Our requirement for turn table 8 station as below;-
1. table plate size 800 mm
2. thiskness of plate 25 mm
3. table plate use AL material
5. Speed per station 10 sec.
6. Distance are 75 mm, refer form CG point

Can we have basic equation for estmate? pls advice

om_tech_support_JT
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### Re: DG Rotary Hollow Actuator Specifications

Hi Pichate,

We have motor sizing calculation notes here:
http://www.orientalmotor.com/products/p ... lation.pdf

We also have a FREE online motor sizing tool here:
http://www.orientalmotor.com/support/motor-sizing.html (registration required)

SIZING CALCULATIONS:
INERTIA = MD²/8 = 8.4kg * 0.8m² / 8 = 0.672 kg*m²
TORQUE = negligible since there's only friction torque, and it's a direct drive setup.
SPEED = 45 deg in 10 seconds.
75MM OFFSET FROM CENTER => increases inertia
=0.672 kg*m² + 8.4kg * 0.075m² = 0.71925 kg*m²
CONVERSION: 39324.814 oz.in²

According to page D-172, Load Inertia - Positioning Time charts, a DG130R-ASAA model would be able to do your positioning move 45 deg in approximately 0.55 seconds. Please review the page here:
http://www.orientalmotor.com/products/p ... imo_dg.pdf

Let me know if you have any questions. I can also be contacted @ [email protected].

lcamcas
Posts: 2
Joined: Tue Mar 31, 2015 12:13 pm

### Re: DG Rotary Hollow Actuator Specifications

Hi.

I have a similar application but I´m having problems using the sizing tools. I want to use a DG130R-ARMAD-3 but I don´t know the value I have to use in transmission belt, Rotor inertia Jo and gear ratio i. I want to index 90°in 2 seconds.

4 loads of 7.5 Kg separated r=200mm of the center.
A round table D=600mm and T=25 of aluminium.

is it posible do it using that actuator? please add the calcs to see the values you used.

om_tech_support_JT
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### Re: DG Rotary Hollow Actuator Specifications

Hi lcamcas,

http://www.orientalmotor.com/support/motor-sizing.html
-registration is required.

I do not have enough information yet to perform a sizing calculation using our online sizing tool. I need to know what shape those 7.5 kg loads are so I can calculate their off-centered inertias. Then I need clarification on the motion profile: 90 deg in 2 seconds. I need to know how much of those 2 seconds are used for acceleration/deceleration such as in a trapezoidal motion profile. I also need to know if you plan on using support bearings or do you plan on our motor supporting the whole load. If you use support bearings, I need the coefficient of friction.

For the transmission belt/pulley ratio on the sizing form, leave this blank. For the DG130R-ARMAD2-3 (newer model), we give the inertia of 5225.4 oz-in^2 which is at the rotary table after 18:1 gear reduction. I would put in the 5225.4 oz-in^2 value in the J0 field, and input gear ratio 'i" at 1.

Once you provide those values, then I can generate a report using our sizing tool.

lcamcas
Posts: 2
Joined: Tue Mar 31, 2015 12:13 pm

### Re: DG Rotary Hollow Actuator Specifications

Hi.

Loads are cylindrical with a diameter of 145mm. The two seconds indexing time don´t has restrictions could be 1 acceleration second and 1 deceleration second it is only for keep the process in time even if it is shorter could be better. The idea is not to use bearings but if the loads are too much for this table we could go for the bigger one.

om_tech_support_JT
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### Re: DG Rotary Hollow Actuator Specifications

Hi lcamcas,

I have used your information to generate a motor sizing report by using our online motor sizing tool. Please see attached file below for input variables and calculations.

Based on the report, your REQUIREMENTS are:

PEAK TORQUE = 8.176 Nm (with 1.5:1 safety factor)
MAX SPEED = 10 RPM based on 90 deg in 2 seconds with 0.5 second for accel/decel

The DG130R-ARMAD2-3 rotary table actuator can output 12 Nm torque, and run up to 200 RPM. We're OK there. However, it can only handle an inertial load of 0.5685 kg*m^2 inertial load. This is not even close to your 2.169 kg*m^2 so it probably won't work properly.

The DG200R-ARMAD2-3 rotary table actuator can output 50 Nm torque up to 110 RPM, and it can handle up to 2.86584 kg*m^2. I would recommend going one size bigger to be safe.