How do i slow down a telescope motor?
physicsdude2014 asked:
I have an old Meade lx emc sct telescope and the motor drives it too fast. It goes 5 minutes of right ascension too fast per hour. I called Meade and all they would tell me is to send it in or do an exchange program for another telescope. Is there any way to adjust it so that it moves at the right speed by using weights or something?
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I have an old Meade lx emc sct telescope and the motor drives it too fast. It goes 5 minutes of right ascension too fast per hour. I called Meade and all they would tell me is to send it in or do an exchange program for another telescope. Is there any way to adjust it so that it moves at the right speed by using weights or something?
October 28th, 2009 at 8:23 pm
One way would be to put a potentiometer (like a volume control) in the motor’s circuit to vary the speed. If you have no idea what I’m talking about, get an electrically savvy friend to assist you. This is pretty easy thing to do, for a tinkerer, and you would have a useful manual speed control. harmonograph
November 1st, 2009 at 1:22 am
Is this an AC or DC powered motor? Does it plug into the wall or run on batteries? If it’s AC, it needs an adjustable frequency power source to control its speed, and these are no longer made, If it’s DC, you should be able to slow it down by altering the voltage.
These older mounts are cranky. You may be better off in the long run remounting it on a more modern mount. Geoff G
November 1st, 2009 at 5:56 am
The majority of motor drives I have seen use stepper motors internally. This makes the speed of the motor easy to precisely control and largely independent of variables such as the load on the mount or the supply voltage.
I’d open the drive up and take a look at the motor. If there are four or more wires leading to it then that is a good indication that it is a stepper. The good news it that once you have found what to change it is likely to be very cheap (less than a dollar). The bad news is that you really need to understand the drive circuitry to know how to adjust it. I would begin by examining the associated circuit board and see if there are any twiddleable components on it - you are probably looking for either a preset potentiometer (see for a picture) or a variable capacitor (look similar, but you may see layers of metal plates).
If you have either of these I would suggest noting the original position, tweaking them slightly, and seeing what if anything has changed. If you don’t have such components the values will be set by fixed components on the board that will need either changing or supplementing. However, that really needs and understanding of the circuitry. If you can take a _good_ photo of the both sides of the board I’ll be happy to have a look and see if I can offer any suggestions but I’m not making any guarantees. Andrew S
November 2nd, 2009 at 8:55 am
Might try here for information on your scope - Nyx