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Cge pro anyone?

eric.remy@...
 

New member here.
I just got this used mount and I've been looking to try an onstep conversion for a while.
Has anyone ever converted the CGE Pro?
I've seen at least 3 CGE mods and will be using those as a ''guide'' since they are close in similarity.

Khalid Baheyeldin
 

Hello Eric,

You will be the first one to attempt the CGE Pro.

One difference (from past discussions) is that it has 255 teeth on the worm wheel.

Another thing to consider is that all the conversions required drilling the housing
to make room for a pulley (e.g. 45T to 15T for 3:1 reduction). It is possible to use
a precision geared stepper, e.g. like this one with 10:1 or a similar one with 5:1,
and get 15T to 15T pulleys (1:1). That way you will not need to drill.

Someone attached such as motor using perforated metal strip like the one used
for HVAC ducts. Another way to make the conversion simpler.

If you need to ask specific question, I am sure those who did it will answer them.

Please share your final project pictures and details.

Best wishes ...

eric.remy@...
 

Thanks Khalid.
It's going to be interesting to say the least. I have already ordered the .9 degree steppers and the electronics. 

Khalid Baheyeldin
 

On Wed, Sep 11, 2019 at 06:15 PM, <eric.remy@...> wrote:
I have already ordered the .9 degree steppers and the electronics.
The CGE and CGE Pro are big mounts.

Check the torque and current on the specification sheet for the motors you ordered.

The more torque, the more likely the mount will not stall and be able to take the load.
More current usually means more torque, but not necessarily. A side effect of higher
current is more heat, and if the motors are inside the mount, you'd better add a fan
like some did for the CGE.

If the motor has built in gearheads, then that means more reduction, and the motor
need not have as much torque as motors that don't have them.

George Cushing
 

Please document your pioneering effort and share it here. I hear a lot of complaints about the way the Celestron Nexstar system performs in the CGEM Pro and others may be interested. Celestron replacement motor control boards are pretty expensive.  There is a ready market for drive system parts from your mount, so your should be able to recover the cost of the conversion.

Good luck!

ckampf
 

Hi,
I have converted my CGE pro some time ago.

It's still not well tested since I have currently some problems with the roof of my backyard observatory.

Construction used chinese 200 steps steppers, a MaxPCB2 with a Teensy3.5 and TMC2130 drivers. I used belts to connect the motors with the original worm. I am using also the original limit switches of the CGE pro.

Here is a picture of the prototype:


cheers & clear skies
Christian

Khalid Baheyeldin
 

Christian,

Questions:

1. What amp and torque are the motors? Or a link to them.

2. What size pulleys are you using?

3. The white bracket, is it custom made (or printed) or from the original mount?

ckampf
 

Hi Khalid,

the motors are Quimat Nema 17 steppers with 1.7A, 0.59Nm (84 oz.in), 1.8°

The belts are GT2 and the wheels have 60 and 20 teeth.

The white bracket is printed and just a prototype. The final bracket will be aluminium or steel.

BTW: the original PEC Sensor of the mount is also connected to the MaxPCB2.

Khalid Baheyeldin
 

Thanks for the info. I added it to the showcase page on the Wiki.

eric.remy@...
 

I will post my pictures don't worry.

eric.remy@...
 

I like the way you made your brackets.
I can only put a gear the is not wider than 42mm before hitting the mount body.
Your idea of 60 20 might work with the cge pro.
I also want to save all the limit switches on the mount.

Aisling Lightworks
 

Awesome, I've been hoping to see someone do one of these soon. I've had my eye out for broken ones as the payload is higher than my CGE Let us know how it goes

eric.remy@...
 

Been quite a while but I am getting up and running. Board is done, and already have the right ascention axis purring like a kitten. That last Onstep update really helped. 4 to 1 reduction on the gears.

Aisling Lightworks
 

Looking good, that 4:1 is going to kick ass. I'm at 3:1 and it's JUST enough. Is it going to maintain the original style or will you have to chop up the motor box?

Khalid Baheyeldin
 

On Tue, Feb 4, 2020 at 10:50 PM, Aisling Lightworks wrote:
Looking good, that 4:1 is going to kick ass. I'm at 3:1 and it's JUST enough.
If these are 400 step motors, then 4:1 and 1/32 will get you down to 25,600 steps per degree and 0.14" resolution.

eric.remy@...
 

They are 400 stp motors. 0.14'' is more than enough.

eric.remy@...
 

On Tue, Feb 4, 2020 at 10:50 PM, Aisling Lightworks wrote:
Is it going to maintain the original style or will you have to chop up the motor box?
I was able to keep everything except the motor mounts. They had to be cut off and milled and replaced with angle mounts.

eric.remy@...
 

The motor covers modified.

Aisling Lightworks
 

Awesome. Nice job.

fetoma
 

On Thu, Sep 12, 2019 at 12:07 PM, ckampf wrote:
The belts are GT2 and the wheels have 60 and 20 teeth.
This is 3:1 reduction, not 4:1 correct?