Installing EQ-1 'clock' drive - Voltage required?

[iborg (Philip)]

Hi All


I am adding an EQ-1 drive to my Father's mount. It is setup to run from 4 D batteries, so a nominal 6V.


Does anyone know if it will drive reasonably accurately from 5V? I have checked that it runs, but, hard to judge the actual speed of rotation.


The particular unit is from TUV Rheinland NO: 9832 117-9803.


It looks similar to the Orion EQ-1M


Thanks for any suggestions.


Philip

[JA]

Originally Posted by iborg

Hi All


I am adding an EQ-1 drive to my Father's mount. It is setup to run from 4 D batteries, so a nominal 6V.


Does anyone know if it will drive reasonably accurately from 5V? I have checked that it runs, but, hard to judge the actual speed of rotation.


The particular unit is from TUV Rheinland NO: 9832 117-9803.


It looks similar to the Orion EQ-1M


Thanks for any suggestions.


Philip

Hi Phil,

Fresh new 1.5V batteries will often measure at around 1.55 to 1.6V and most devices will often signal low battery indicators at around 1 to 1.2 V, so your 5V supply, which likely measures at more than 5V will provide the equivalent of at least 1.25V per cell if it were in a 4 cell configuration. I suspect therefore that it would be fine as those voltages would place it within the band of normal operation, albeit at the lower end, but to be certain, test the drive by marking the location /rotation of the output shaft with some tape/texta/added toothpick and allow it to run for 6, 12 or 24 hours and then assess if it moves through 90, 180 or 360 degrees of rotation respectively.

Of course having the correct or enough voltage is one thing, but you also need enough output current from the power supply. In the absence of specifications for the drive motor you can only* try and use it under load (driving the telescope) whilst powering it with your 5V supply at test for rotational speed accuracy as I described above.

*One could also measure the current drawn in normal operation when powered by four 1.5V D cells to get a feel for the output capabilities required from any power supply.

Best
JA

[iborg (Philip)]

Hi JA


Thanks, I thought running it would be the simple thing to do.



If clouds clear well enough, pointing at a star with a cross hair eyepiece and waiting would be adequate. I'm not looking for great accuracy, mainly a longer time in the eyepiece.


Have fun


Philip

[iborg (Philip)]

Hi All


I made a small extension bracket and have it installed and running with a lab supply at 5V. At 5V it pulls 150mA, so should be fine with a USB power bank



I set the setting circle to 0 and a timer for 1 hour. Hopefully it turns close to 15 degrees. If not, I'll set it at 6V, just maybe the motor it the wrong speed for this mount.


Have fun folks


Philip