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1
Mount Support / Re: Retrofitting AstroEQ onto old Meade Starfinder GEM
« on: April 10, 2015, 03:26:39 »
btw i ended up just ordering the servos from pololu. linengineering was going to charge me $150 for a modified servo and another servo distributor said they couldnt do it.
im just going to have my machinist grind the ends as needed. for 1/10th the cost its worth trying.
im just going to have my machinist grind the ends as needed. for 1/10th the cost its worth trying.
2
Mount Support / Re: Retrofitting AstroEQ onto old Meade Starfinder GEM
« on: April 02, 2015, 08:37:30 »
Thanks. I'll ask for the -02 with the lower voltage and inductance spec.
3
Mount Support / Re: Retrofitting AstroEQ onto old Meade Starfinder GEM
« on: April 01, 2015, 23:51:23 »
Thanks for your thoughts. I'd like to try to keep the motor within the enclosure if i can. I'll try the smaller 11.
Because of the custom shafting for the RA gear, I may buy the motor from another supplier.
http://www.linengineering.com/stepper-motors/211.aspx
Which model 11 would work best in regards to the difference in resistance/phase or amp/phase? What is the voltage of the power supply? [nvm i read 12V]
Because of the custom shafting for the RA gear, I may buy the motor from another supplier.
http://www.linengineering.com/stepper-motors/211.aspx
Which model 11 would work best in regards to the difference in resistance/phase or amp/phase? What is the voltage of the power supply? [nvm i read 12V]
4
Mount Support / Retrofitting AstroEQ onto old Meade Starfinder GEM
« on: March 31, 2015, 20:55:33 »
As I mentioned before, I intend to try to retrofit the an old Meade Starfinder equatorial mount with 2 steppers and an AstroEQ.
For the declination axis, I can mount a 60T timing gear to a 15T pinion on the stepper. Using gears and belt from Servocity and the NEMA 14 stepper and bracket from Pololu. The bearing collar, servo arm clamp are custom machined to adopt onto features already machined into the Meade mount.
NEMA 14
https://www.pololu.com/product/1209
General specifications
Shaft type: 5 mm "D"
Steps per revolution: 200
Current rating: 1000 mA2
Voltage rating: 2.7 V
Holding torque: 20 oz·in
Resistance: 2.7 Ohm2
Inductance per phase: 4.3 mH
Number of leads: 4
Lead length: 30 cm
On the RA axis, there is already a ~4" gear and worm gear pair. I am replacing the 120VAC vintage clock drive motor with a NEMA 11 motor. It seems theres only space for a NEMA 11 if i want to fit in the same enclosure and I will have to have the shaft custom machined due to the worm gear end. I'm sort of wondering if its even worth the bother to fit a small motor, made expensive because of the custom shaft. But I dont mind if someone (Tom?) can confirm the torque and specs are compatible and sufficient. If not, then I should be able to create custom machined brackets and coupler to fit a larger stepper in there since I'm not space constrained, but definitely more complicated.
NEMA 11 28x32
https://www.pololu.com/product/1205
General specifications
Shaft type: 5 mm "D"
Steps per revolution: 200
Current rating: 670 mA2
Voltage rating: 3.8 V
Holding torque: 8.3 oz·in
Resistance: 5.6 Ohm2
Inductance per phase: 4.2 mH
Number of leads: 4
Lead length: 30 cm
Any thoughts before I go and buy the parts?
I intend to mount a AT6RC Astrotech 6" richey. Not sure what kind of guiding yet.
For the declination axis, I can mount a 60T timing gear to a 15T pinion on the stepper. Using gears and belt from Servocity and the NEMA 14 stepper and bracket from Pololu. The bearing collar, servo arm clamp are custom machined to adopt onto features already machined into the Meade mount.
NEMA 14
https://www.pololu.com/product/1209
General specifications
Shaft type: 5 mm "D"
Steps per revolution: 200
Current rating: 1000 mA2
Voltage rating: 2.7 V
Holding torque: 20 oz·in
Resistance: 2.7 Ohm2
Inductance per phase: 4.3 mH
Number of leads: 4
Lead length: 30 cm
On the RA axis, there is already a ~4" gear and worm gear pair. I am replacing the 120VAC vintage clock drive motor with a NEMA 11 motor. It seems theres only space for a NEMA 11 if i want to fit in the same enclosure and I will have to have the shaft custom machined due to the worm gear end. I'm sort of wondering if its even worth the bother to fit a small motor, made expensive because of the custom shaft. But I dont mind if someone (Tom?) can confirm the torque and specs are compatible and sufficient. If not, then I should be able to create custom machined brackets and coupler to fit a larger stepper in there since I'm not space constrained, but definitely more complicated.
NEMA 11 28x32
https://www.pololu.com/product/1205
General specifications
Shaft type: 5 mm "D"
Steps per revolution: 200
Current rating: 670 mA2
Voltage rating: 3.8 V
Holding torque: 8.3 oz·in
Resistance: 5.6 Ohm2
Inductance per phase: 4.2 mH
Number of leads: 4
Lead length: 30 cm
Any thoughts before I go and buy the parts?
I intend to mount a AT6RC Astrotech 6" richey. Not sure what kind of guiding yet.
5
AstroEQ Availability / Re: AstroEQ Availability [Currently Unavailable]
« on: February 21, 2015, 02:50:00 »
No worries. Thanks for the response. I'll try to check in later.
6
AstroEQ Availability / Re: AstroEQ Availability [Currently Unavailable]
« on: February 20, 2015, 19:37:26 »
Hi.
I have an old meade portable pier and GEM head (google meade 628, 850 etc). It has an old clock drive running AC power, and no dec control. I'd like to update the RA motor and add a dec motor with steppers. I have the mechanical and machining means to design and fabricate necessary parts (I dont mind sharing the design and CAD files but it would be very specific to my mount), but I need something like the AstroEQ for control.
any units available? ship to US, California? not in a rush with it.
I also have a question about adjusting the axis' manually, will it be ok to physically push the motion with the steppers and everything connected. in other words, is there circuitry in place to protect the boards from back driving the stepper motors. or not a big deal either way.
I have an old meade portable pier and GEM head (google meade 628, 850 etc). It has an old clock drive running AC power, and no dec control. I'd like to update the RA motor and add a dec motor with steppers. I have the mechanical and machining means to design and fabricate necessary parts (I dont mind sharing the design and CAD files but it would be very specific to my mount), but I need something like the AstroEQ for control.
any units available? ship to US, California? not in a rush with it.
I also have a question about adjusting the axis' manually, will it be ok to physically push the motion with the steppers and everything connected. in other words, is there circuitry in place to protect the boards from back driving the stepper motors. or not a big deal either way.
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