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Kencor Telescope drive corrector

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19 replies to this topic

#1 starman876

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Posted 21 March 2018 - 02:38 PM

First time I have seen one of these. Came with the Unitron 145 that arrived today.

 

kencor.jpg

 

kencor 2.jpg

 

 


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#2 starman876

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Posted 21 March 2018 - 02:39 PM

kencor 3.jpg

 

kencor4.jpg


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#3 Masvingo

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Posted 21 March 2018 - 03:58 PM

New to me too, thanks for the pictures.



#4 DAVIDG

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Posted 21 March 2018 - 04:16 PM

 Interesting, got a manual ? I'll guess that the dip switches set the drive rate in the numbers of minutes per day to make 1 rev  and converts that into a frequency. So a drive that is geared to make one rev in 1440 minutes ie Solar rate would need 60.0 hz. To make that drive track at Sidereal rate you would need the frequency to be 60.1 hz which if I understand how it works you would set it at 1436. 

   It looks like it is set for 1553, which again if I understand how it works the frequency would by smaller then 60hz hence it would need to used with the drive that would cause the scope to make 1 rev faster then in 1440 minutes,  and smaller frequency would slow the drive down to have it  track correctly.

 

                       - Dave 



#5 starman876

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Posted 21 March 2018 - 04:24 PM

the manual might be in the other boxes not delivered yet.  There are also the two swtiches above the dip switches which are called coarse/ fine selector switch which are 20% and 5%.  


Edited by starman876, 21 March 2018 - 04:28 PM.


#6 deSitter

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Posted 21 March 2018 - 05:11 PM

First time I have seen one of these. Came with the Unitron 145 that arrived today.

 

attachicon.gif kencor.jpg

 

attachicon.gif kencor 2.jpg

Found in 1978 June S&T

 

-drl

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#7 starman876

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Posted 21 March 2018 - 06:27 PM

Found in 1978 June S&T

 

-drl

now see if you can find a manual wink.gif



#8 deSitter

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Posted 21 March 2018 - 06:54 PM

Should be able to figure it out. A 4-position DIP switch like that takes 16 possible values - and likely only 10 of them are valid, 10s - 100s - 1000s then units (of time no doubt). So you have a three digit number representing the time correction. 20-5 could refer to the speed-up/slow-down applied when one depresses the FAST and SLOW buttons.

 

-drl



#9 DAVIDG

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Posted 21 March 2018 - 07:03 PM

the manual might be in the other boxes not delivered yet.  There are also the two swtiches above the dip switches which are called coarse/ fine selector switch which are 20% and 5%.  

 What I believe the switch does is adjust by how much the drive rate is increased or decreased when you push the buttons on the side. So the 20% is for coarse adjustments and the 5% is fine adjustment ie  guiding for astrophotography. 

 

                  - Dave 



#10 deSitter

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Posted 22 March 2018 - 12:18 AM

 What I believe the switch does is adjust by how much the drive rate is increased or decreased when you push the buttons on the side. So the 20% is for coarse adjustments and the 5% is fine adjustment ie  guiding for astrophotography. 

 

                  - Dave 

Yes, and so the correction factor is of the form 0.xyz and represents - what? Whatever is set in UNITS I'd guess, and you set that based on the RPM of the particular synchronous motor to which this gets attached?

 

-drl



#11 DAVIDG

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Posted 22 March 2018 - 08:37 AM

 Units = ones places ie 0 to 9  so you have 4 sets of switch  ie 1000ths 100ths 10's and ones . Each bank of switches allows you to set a value between 0 to 9 so you can set a value between 0000 to 9999. The switches blanks are most likely coded in Binary Coded Decimal ie BCD .  Since this unit was designed in the late 70's it is most likely a circuit to designed to be a "divded by N" . So it takes a frequency generated by a quartz crystal and divides it by the number set on the switch to output a frequency that is around 60hz. The unit can be designed so the switch set the frequency, or the drive rate in minutes per day or the period  ( 1 / frequency).  

  Most telescopes made up the mid 80's had a clock drive designed to track at solar rate (1440 minutes per day) and used a 60 hz syn motor of various RPM to achieve that rate. So to drive the scope at that rate the corrector needs have an output of 120 volts AC at 60hz. To drive at Sidereal rate you would need 120 volts at 60.167 hz , and Lunar rate is around 58Hz. 

 

                    - Dave 


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#12 starman876

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Posted 22 March 2018 - 09:32 AM

next step will be to test it and see if it still works. 



#13 DAVIDG

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Posted 22 March 2018 - 09:41 AM

Looking forward to the test.  If it does come up, measure the AC voltage and if your meter has a Frequency function what the frequency is. If my guess is right on how it is  set then the frequency should be around 56Hz with the values set on the switches.

 

                              - Dave 


Edited by DAVIDG, 22 March 2018 - 05:22 PM.


#14 starman876

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Posted 22 March 2018 - 10:40 AM

Looking forward to the test.  If it does come up, measure the AC voltage and if your meter has a Frequency function what the frequency is. If my guess is right on how it set then the frequency should be around 56Hz with the values set on the switches.

 

                              - Dave 

I do have a frequency setting on my Fluke DMM.  will let you know.  It also sounds like this device could make drives for the Europe work that require 50 cycles.


Edited by starman876, 22 March 2018 - 10:42 AM.


#15 starman876

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Posted 22 March 2018 - 09:25 PM

Picture of bill of sale

 

driv corect.JPG

 

catalog

 

drive correct 1.JPG

 

 

 

 


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#16 deSitter

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Posted 22 March 2018 - 09:37 PM

Pretty cool :)

 

-drl



#17 Brianfromsyr

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Posted 14 October 2021 - 03:33 PM

Wow.
I know this is an old post.
I have the Kajers 7700. Bought it a few years back.
Just getting around to want to use it.
Would love to find that publication.
There was no manual for mine.

Edited by Brianfromsyr, 14 October 2021 - 03:34 PM.

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#18 Jaylab

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Posted 14 October 2021 - 06:35 PM

I built one based on an article in Sky and Telescope called the West Drive Corrector, and it worked fine. It was probably published in the 1990s.

 

Plug in a synchronous motor based clock and note how fast or slow it runs with various settings.

 

-Jay-



#19 ccwemyss

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Posted 14 October 2021 - 07:58 PM

Wow.
I know this is an old post.
I have the Kajers 7700. Bought it a few years back.
Just getting around to want to use it.
Would love to find that publication.
There was no manual for mine.

PM me with an email. I have the Kencor manuals as pdfs, but they are up to 18MB in size. 

 

Chip W. 



#20 Brianfromsyr

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Posted 15 October 2021 - 12:33 PM

Thank you!


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