Username:

Password:

UKAI is moving to Facebook

Author Topic: REVAMP MY HD MOUNT  (Read 3717 times)

0 Members and 1 Guest are viewing this topic.

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
REVAMP MY HD MOUNT
« on: 12:44:07, 10 March, 2016 »
Hi folks i'm seeking help with this heavy duty telescope mount I bought quite a few years ago  :D.
It is little used because of issues with clutch locking.  Also I think the motors on the RA and DEC run on 240v of which i'm none to keen to use on cold damp nights :no:.

Details:  The RA and DEC axis are real heavy duty bearings, i've seen these type before in the car industry used on transfer beds and rolling lines.
Motors and gearbox:
RA  - Crouzet model type 82344  1/3RPM 240v 50~
DEC - Crouzet model type 82474  1/4RPM 240v 50~
(gearbox has plastic gears)
UPDATE: The gearbox is 1800:1 as the motor has a base speed of 600rpm and the output is 0.333rpm (1/3rpm)

Control box: 
Hand built blackbox with Starchaser printed on the front, four buttons and a trim pot ( for speed control of RA i presume).  On/Off toggle switch.
--------------------------------------------------------------------------------------
I am hoping that I could replace the motors/gearbox with a stepper type that I could use my spare EQ4/5 controller.  My problem is how do I match up the motors to suit 1/3 rotation per minute.

John..
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Online chris.bailey

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10012
  • If at last you do succeed, don't try again
    • Rosemount Observatory
Re: REVAMP MY HD MOUNT
« Reply #1 on: 13:08:44, 10 March, 2016 »
Tom is your man on this one but i suspect it is no mean task.

Not sure I would want to plug that into the mains either!
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #2 on: 11:22:08, 13 March, 2016 »
I think i've found a replacement motor for my HD EQ Mount, it has a 0.6rpm @ 12v clockwise rotation. A little experimentation will prove whether I can control the rpm speed via voltage/current control..

John..
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline tomhow

  • Tom How
  • Galactic Poster
  • ******
  • Posts: 3137
  • Making equipment is far more fun than buying it.
    • The Curdridge Observatory
Re: REVAMP MY HD MOUNT
« Reply #3 on: 11:30:31, 13 March, 2016 »
That is a stunning mount! 240v motors do sound pretty terrifying. But Crouzet are a top manufacturer. Unfortunately I don't know much about the EQ controllers.

If you just want it to track, then finding a motor shouldn't be too hard.

If you want GOTO (i.e. slewing) then things get a little more complicated. You then need something that can go slow enough for sidereal tracking, but also something that can go fast enough to slew (e.g. 2 degrees per second).

What is the tooth count on the two big wheels?

Tak Sky 90, Atik 490, Homemade Mount, OAG, Lodestar

The Curdridge Observatory

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #4 on: 12:30:02, 13 March, 2016 »
I have no idea really, as best as I can judge (without stripping it down ) the RA is 285mm across giving it a 870mm circumference, the teeth/worm groove is 2mm aprox giving a count of about 435 teeth/grooves.  The RA Crouzet motor has a 1/3 minutes RPM.  From experimenting with my EQ4/5 mount motors they only have about 35deg or 1/10th RPM, I was wondering if I could use 3:1 gears to increase this to 1/3rd RPM ??

John..
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline tomhow

  • Tom How
  • Galactic Poster
  • ******
  • Posts: 3137
  • Making equipment is far more fun than buying it.
    • The Curdridge Observatory
Re: REVAMP MY HD MOUNT
« Reply #5 on: 13:55:16, 13 March, 2016 »
1/3 minute RPM makes sense. 180 seconds per worm revolution. That would require 480 teeth on the wheel. That is a typical number.

EQ4/5 motors will be slower out of the box because they are for much smaller wheels, usually 180 teeth, so running at about 1/8rpm. Sometimes the controller box allows you to adjust the ratio of the final drive. I was able to use a Meade DS motor kit to run my 360 tooth drive some years ago. The more teeth, the faster the motor has to go. It would certainly be possible to get up and running with a Meade DS motor kit*, if you can find one. Some assembly required :)

Adding more gears often adds more problems than solutions and unless the controller is adjustable you're unlikely to hit just the right speed.

What is it that you are actually trying to do? If you just want sidereal tracking, then it would be a case of finding a geared stepper about the right speed and hooking it up to some kind of USB stepper controller and telling it to go the right speed.

If you want full-on GOTO then that is another story.

You might find the section on this page "Now you are going to need some motors" helpful for thinking about motors. http://astro.neutral.org/arduino/how-to-write-arduino-telescope-goto-mount-controller.shtml

*As well as the old meade DS motor kit, the controllers and motors from other Meade products like LXD55, LXD75 etc can have the final drive adjusted to suit bespoke mounts.
Tak Sky 90, Atik 490, Homemade Mount, OAG, Lodestar

The Curdridge Observatory

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #6 on: 09:05:57, 14 March, 2016 »
The end result is to use this mount in a fixed position, it being really heavy duty and rock solid.  As for 'goto' it is not important but being able to control sidereal is (planetary, solar etc).   Thank you Tom, I'll have a good look around  :D
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline Bazzaar

  • Poster God
  • *****
  • Posts: 979
Re: REVAMP MY HD MOUNT
« Reply #7 on: 09:35:07, 14 March, 2016 »
I dont think simple voltage control of a DC motor will work very well. At any fixed voltage the speed will change with load and possibly temperature. So the weight of scopes and the balance will change the speed. You will need a closed loop servo system with a DC motor.

Baz
Tal 200k, SW 200P, iOptron iEQ45 pro, HEQ5 pro, QHY5III174m, QHY5L II mono, Samsung SBC 2001, SharpSky focuser, Zwo ADC,  Celestron 15x70 bins,

Online chris.bailey

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 10012
  • If at last you do succeed, don't try again
    • Rosemount Observatory
Re: REVAMP MY HD MOUNT
« Reply #8 on: 10:08:04, 14 March, 2016 »
EQmod has the ability to input custom ratios so an EQ controller could form the basis for it is you use EQmod. A fair bit cheaper than something like ServoCat
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #9 on: 10:25:24, 15 March, 2016 »
I dont think simple voltage control of a DC motor will work very well. At any fixed voltage the speed will change with load and possibly temperature. So the weight of scopes and the balance will change the speed. You will need a closed loop servo system with a DC motor.

Baz
The current AC system uses this method of control via a Trim pot.  It has very fine adjustment range 0-10, 5 being nominal sidereal speed.  After a little experiment I found that the pot allows 10seconds plus and minus per revolution of nominal.  I am trying to find stepper motors to replace the current AC motors and still keep the original gearboxes but i'm finding it difficult.  So that is why I was thinking of changing the AC motor for a DC motor, I should be able to use a similar controller to obtain sidereal speed.

John..
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline tomhow

  • Tom How
  • Galactic Poster
  • ******
  • Posts: 3137
  • Making equipment is far more fun than buying it.
    • The Curdridge Observatory
Re: REVAMP MY HD MOUNT
« Reply #10 on: 11:19:36, 15 March, 2016 »
McLennan Servo Supplies do some nice geared stepper motors with similar ovoid gearboxes. I use the 542 model all the time for electric focusers etc.

http://www.mclennan.co.uk/products/geared-stepper-motors

http://www.mclennan.co.uk/product/p542-geared-stepper-motor

e.g. http://uk.rs-online.com/web/p/stepper-motors/3514647/
Tak Sky 90, Atik 490, Homemade Mount, OAG, Lodestar

The Curdridge Observatory

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #11 on: 12:26:45, 15 March, 2016 »
Cheers Tom, these Mclennan motors might be just what I'm after  :D
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline tomhow

  • Tom How
  • Galactic Poster
  • ******
  • Posts: 3137
  • Making equipment is far more fun than buying it.
    • The Curdridge Observatory
Re: REVAMP MY HD MOUNT
« Reply #12 on: 16:32:15, 15 March, 2016 »
I've always wanted one of their 1500:1 models and try and make it direct drive a widefield camera. Sidereal won't be far off 1 step per second.
Tak Sky 90, Atik 490, Homemade Mount, OAG, Lodestar

The Curdridge Observatory

Offline jhughe22

  • Full Member
  • ***
  • Posts: 458
  • Don't get mad, get smart!
Re: REVAMP MY HD MOUNT
« Reply #13 on: 16:45:16, 14 April, 2016 »
After much searching I have found some useful information about my RA drive motor, apparently it runs at a base speed of 600RPM and the gearbox output is 1/3RPM (0.333RPM), this would make the gearbox a 1800:1 ratio.  If I want to just replace the motor I will need a stepper motor capable of 600RPM or greater.  Now the question is were can I find a 48mm Dia stepper with a 2mm shaft that can run at 600RPM nominal and be able tp achieve even faster speeds.  I bagged a bargain on ebay (5 Axis CNC Breakout Board Adapter Stepper Motor Driver Mach3 + USB Cable Tools) i'm hoping this will be able to drive the steppers.
I also saw on ebay a 0.9deg Nema 17 Stepper Motor Bipolar 2A 46Ncm/65oz.in 42x42x48mm 4-wires DIY CNC, but i'm unsure it can reach the speeds I require.

oh well back to the research

John..
8" f/5 Sky-watcher 200P f=1000,  6" f/9 Ritchey-Chrétien Revelation Astro f=1370, 3.5" f/10 Meade 90 with 2" focuser mod f=900, 3.5" f/13 Maksutov-Cassergrain f=1200...  Heavy Duty EQ est-60lb payload.  iOptron Minitower v2, Skywatcher SupaTrak, and a damaged EQ-3 Mount. Latest;- EQ-5 with dual drive.
Camera's;- Nikon D5000, Sony Nex5, Samsung NX2000, Altair GPCAM AR0130C, Celestron NexImage SSI

Offline tomhow

  • Tom How
  • Galactic Poster
  • ******
  • Posts: 3137
  • Making equipment is far more fun than buying it.
    • The Curdridge Observatory
Re: REVAMP MY HD MOUNT
« Reply #14 on: 08:47:12, 15 April, 2016 »
I wouldn't try running stepper motors at 600RPM. Not to say it couldn't be done, but that sounds quite fast for a stepper motor. Depends on huge number of factors.

Stepper motor torque reduces as speed increases. It depends on the motor but at that sort of speed I would expect to only have 10-20% of the torque available.

Tak Sky 90, Atik 490, Homemade Mount, OAG, Lodestar

The Curdridge Observatory

 

ukbuysellRemote Imaging from AustraliaSharpSkyblank APTUKAI on Facebook
Powered by SMF 2.0.15 | SMF © 2006, Simple Machines LLC
DarkBreak by DzinerStudio. Theme modified by The UKAI Team

Page created in 0.311 seconds with 36 queries.
TinyPortal © 2005-2012