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Xavier has kindly given me permission to use his images of his MkIV. Now fitted with belt driven stepper motors by AWR. Xavier has chosen to use an FS2 handset to achieve GOTO and slewing. AWR Technology has a long history of providing drives for many kinds of telescope mountings of all sizes and ages. Their experience allows them to optimise their customer's requirements. Even including massively heavy antiques.
Here is the belt-driven stepper motor for the Polar Axis drive. Note the neatness of the cabling and newly constructed bracket work. The MkIV is rather heavy, with considerably more friction than mountings fitted with ball or roller races. This requires a large motor and a lot of torque to move the heavy telescopes often fitted to these old Fullerscopes mountings. The belt drive achieves a very useful 2.7x gain in torque to drive the 359 tooth worm/wormwheel slow motions of the MkIV.
A more straight on view showing the compact and tidy arrangement of the stepper motor. Its belt drive system is clearly shown fitted to the original Fullerscopes worm housing. The use of belt drive nicely avoids having an extended drive train on the end of the worm housing. Providing superb compactness and a tidy appearance.
An overhead view of the Declination drive. Again using quite a large stepper motor and belt drive to provide enough torque. The power and control cables are all neatly clipped to avoid tangles.
The polar axis stepper motor is just visible below the Declination axis casting.
Another view of the Declination motor and neat, toothed belt drive. The MkIVs clutch adjusting knob is just visible behind the stepper motor support bracket.
I can only imagine how much of an improvement this system is over the original Fullerscopes synchronous motor drives. Any rate of slewing is an advantage over having to release the clutches to allow manual slewing. The tendency, if one forgets the clutches, is for the worms to rake across the teeth of the worm wheels. Fortunately they are fine toothed and tough bronze. Clutch adjustment is always a tiresome exercise with constant worries over whether the drive has actually been taken up. Just reaching the clutch adjustment knobs is difficult enough for a MkIV on a tall, refractor pier like mine. Not nearly so tiresome on a more typical, reflector mounting, of course.
The only downside is the cost of the entire system. Against which much be balanced the cost of any new, GOTO mounting at today's prices. Often with the consequence of a greatly inferior load capacity. Not to mention the shrunken dovetail/wedge system instead of widely spread full mounting rings.
Xavier has kindly provided the following details:
About the motors:
The motors are Mclennan HSX 23HSX-202.
More information at:
http://www.mclennan.stepper/hsxsteppermotors.23hsx-202
Motors and mount details:
Telescope RA ratio: 359
RA gearbox ratio: 38/14
Motor STEPS/REV: 200
Telescope DEC ratio: 359
DEC gearbox ratio: 38/14
Motor STEPS/REV: 200
Teleskop-Express: GoTo stepper motor control FS2 - 12-40V version
Browse Album :: Fullerscopes MK-IV
New-life-for-Fullerscopes-MK-IV
I can only imagine how much of an improvement this system is over the original Fullerscopes synchronous motor drives. Any rate of slewing is an advantage over having to release the clutches to allow manual slewing. The tendency, if one forgets the clutches, is for the worms to rake across the teeth of the worm wheels. Fortunately they are fine toothed and tough bronze. Clutch adjustment is always a tiresome exercise with constant worries over whether the drive has actually been taken up. Just reaching the clutch adjustment knobs is difficult enough for a MkIV on a tall, refractor pier like mine. Not nearly so tiresome on a more typical, reflector mounting, of course.
The only downside is the cost of the entire system. Against which much be balanced the cost of any new, GOTO mounting at today's prices. Often with the consequence of a greatly inferior load capacity. Not to mention the shrunken dovetail/wedge system instead of widely spread full mounting rings.
Xavier has kindly provided the following details:
About the motors:
The motors are Mclennan HSX 23HSX-202.
More information at:
http://www.mclennan.stepper/hsxsteppermotors.23hsx-202
Motors and mount details:
Telescope RA ratio: 359
RA gearbox ratio: 38/14
Motor STEPS/REV: 200
Telescope DEC ratio: 359
DEC gearbox ratio: 38/14
Motor STEPS/REV: 200
Teleskop-Express: GoTo stepper motor control FS2 - 12-40V version
Browse Album :: Fullerscopes MK-IV
New-life-for-Fullerscopes-MK-IV
Note: I have enlarged Xavier's original images in PhotoFiltre.
Click on any image for an enlargement.
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6 comments:
Hi Chris, Xaviers mods look really good. I have finally managed to change my Alt spindel to stainless but have given up on the RA as its to difficult to remove the original steel bar.
Next I plan to machine some new worms as mine are very rusty after that I should be able to get to use the mount.
Clear skies
Barry
Hi Barry
Have you removed the locking screw/pin from the RA casting? There may be one on either side if you rub the paint away where they should be. The pin or headless screw may need drilling out with larger and larger drills before the remaining shell can be removed with long nosed pliers.
I found that one of the shafts needed to be "unscrewed" to get it out. This risked surface damage to the shaft from the huge gripping pliers but I was already committed to stainless steel and had the new shafts ready.
What I didn't do and regretted later was not dimpling the side of the shaft where the new screws grip. I metric threaded new oversized holes on either side.
My RA worm is not plated and also rusts rapidly. I asked Beacon hill for a stainless worm but he can only offer his own worms and wheels. Which are much coarser than the Fullerscopes and unsuited to the slip ring design of the MkIV.
Do keep us informed of your progress. :-)
Thanks
Chris
Thank you, Chris, for your review. Well done.
Did the first test with the mount. The goto works very good. I'm impressed with the accuracy of the mount. The worm/worm wheel is of outstanding quality.
About the budget. Finally the cost of the mount will only be a fraction of a new mount.
A new mount with this loading capacity costs about 5.000Euro. The total budget for the transformation will be about 1.000Euro.
The result will be a fully functional classic mount with high loading capacity and a good accuracy.
I'll keep you informed about the next steps.
Xavier
Hi Xavier… I need you for my fullerscopes. Where I can contact you? Thanks David’s
I am afraid it is not as easy as that.
I have had no contact with Xavier for a very long time.
His comments above are nine years old.
I doubt he still reads my blog.
After hard drive failures I have no email address.
Chris
I have just found his website:
http://debeerst.ning.com/page/vintage_telescopes
It shows a MkIV.
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