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Losmandy G11 RA and DEC motors

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#1 buckeyestargazer

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Posted 16 February 2011 - 01:49 PM

Does anyone happen to know the specs on the Losmandy G11 RA and DEC motors, and/or recommend a replacement motor? What kind of motor would work in place of the stock motors?
Thanks in advance.

#2 dale c

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Posted 16 February 2011 - 02:06 PM

As far as I know they are using stock geared stepper motors. If you look at the back of the motor there is probably the manufacturer and model number listed. The specs can be found on line and then you can check other geared stepper motor makers vor the corresponding specs.
Dale

Losmandy says the g11 RA drive is 0.5 arcseconds per step. The burgess PN on mine indicates a unipolar stepper motor. So a suitable replacement would be a a unipolar 12v stepper with a motor/gearbox combination that results in 7200 steps per revolution of the output shaft. It would also have to be the proper shape and output shaft diameter to match the motor used.


#3 buckeyestargazer

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Posted 16 February 2011 - 04:24 PM

The only thing that's on the back of the original motor is "Made in Taiwan" :foreheadslap: The difficult part is finding a motor with the right center rotating pin the sticks out of both ends, not just on the pinion/gear end.

#4 saadabbasi

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Posted 16 February 2011 - 04:55 PM

If you have Gemini, you'll have servo motors, not stepper. Make sure to take that into account.

And why not contact Losmandy for the motors? You could also get the more beefy Maxon motors.

#5 buckeyestargazer

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Posted 16 February 2011 - 05:02 PM

If you have Gemini, you'll have servo motors, not stepper. Make sure to take that into account.

And why not contact Losmandy for the motors? You could also get the more beefy Maxon motors.


I have contacted Losmandy, and a new motor is on the way. But I like to tinker and was just curious if I could find a compatible motor to play around with. The maxon motors would be nice, but that would require spending $300 for a new servo unit (motor, housing, pc board etc) vs. the much less expensive standard servo motor that I can replace without having to buy the whole unit.

#6 orlyandico

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Posted 16 February 2011 - 10:08 PM

This German company http://www.astro-electronic.de/ makes GoTo drives for a lot of stepper mounts including the non-Gemini G11. If you look at their prices its actually cheaper than the real Gemini! (if you can buy one)

You can use the original motors or replacement motors with lower gear ratio so that GoTo's don't take forever.

http://www.astro-electronic.de/g11.htm

I suspect they would know what motors are a good replacement.






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