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Squeek when gotoing....az eq6

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#1 HowardK

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Posted 19 August 2013 - 10:45 AM

My AZ EQ6 works great in alt/az with 2 scopes in parallel.

But i have this squeeky sound from the RA axis when she goto's.

Tracking and slewing are fine.

Anyone else notice this?
What could it be?

#2 HowardK

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Posted 20 August 2013 - 09:38 AM

So...nobody else has the squeek when goto ing?

#3 Jesus Munoz

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Posted 20 August 2013 - 12:38 PM

A friend of mine have an Orion Atlas that sounds very bad when gotos are performing, but tracking is great. It is just sound.

#4 Starhawk

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Posted 20 August 2013 - 12:46 PM

This is the first report I've read on this mount at all.

Can you manually drive the two axes and find the sound? What I have in mind is drive the altitude/ dec axis separately from the Azimuth/ RA axis and see which is making it?

Now, is the sound cyclic or continuous? High or low pitch? Could it be described as groan or scraping noise? Does it happen at a specific part of the travel on the mount? try touching external components on the axis moving when you hear the sound and see if it stops. A rub in a housing might sound like that. Does loosening the clutches make it go away?

You may want to just go ahead and talk to Orion and see what they say, though.

-Rich

#5 HowardK

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Posted 20 August 2013 - 01:44 PM

It's the RA axis
Groan..medium pitch
Only when goto....why would that be?

#6 rmollise

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Posted 20 August 2013 - 01:45 PM

Because that's when it's slewing at full speed. In my experience, sounds like this have two main causes:

Insufficient power.
Poor balance.

#7 HowardK

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Posted 20 August 2013 - 02:10 PM

Thans Rod

#8 HowardK

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Posted 20 August 2013 - 02:17 PM

I think power is fine... HC shows me...11.4 amps

Balance.....not sure....RA axis too stiff even with the clutch loosened to tell.

Will mess with it some

#9 Christopher Erickson

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Posted 20 August 2013 - 02:20 PM

An excellent worm gear lubrication is a 3:1 blend of Lubriplate 105 and Nye Fluorocarbon Gel 868H.

That should solve your squealing slews and lower the wear on the gears.

This formula is specifically for low-speed, high-ratio worm drives and wouldn't be appropriate for high-speed automotive or power tool worm drives.

Make sure to get every last spec of the old lubrication out of the worms before putting in the new stuff.

#10 HowardK

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Posted 20 August 2013 - 02:44 PM

Thanks but i don't think that's necessary.

#11 Starhawk

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Posted 20 August 2013 - 02:55 PM

Astro Physics hubs are stiff even with the clutches open as well. Here's how to balance in that condition:

Turn the scope to equatorial configuration.

Orient the RA axis so the scope is one side of the mount and the counterweight arm is level.

Get to gross balance so it stays still in this configuration.

Nudge the counterweight arm up and down with the same amount of force (or what feels the same).

As you do this, observe to see which direction it stops the fastest in. Look for the direction it keeps going in- if it is with the counterweight dropping, then you are balanced too heavy. If it is with the scope dropping, then you are arm light.

Adjust the weight(s) until the arm moves the same amount with repeated nudges in both directions.

-Rich


I think power is fine... HC shows me...11.4 amps

Balance.....not sure....RA axis too stiff even with the clutch loosened to tell.

Will mess with it some



#12 rmollise

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Posted 20 August 2013 - 04:06 PM

I think power is fine... HC shows me...11.4 amps

Balance.....not sure....RA axis too stiff even with the clutch loosened to tell.

Will mess with it some


That's VOLTS that the SynScan displays, quite a different thing, and if accurate, that is on the low side. ;)

#13 HowardK

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Posted 20 August 2013 - 04:26 PM

How many volts should it show Rod?

#14 HowardK

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Posted 20 August 2013 - 04:28 PM

And the red power light stays lit.

I think this blinks if not enuf power....?

#15 rmollise

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Posted 20 August 2013 - 05:47 PM

How many volts should it show Rod?


I would hope at least 12-volts with a fully charged battery.

#16 HowardK

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Posted 21 August 2013 - 03:42 AM

Thanks

#17 orlyandico

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Posted 21 August 2013 - 05:16 AM

Rich -

I am going to try something with my AP mount.

Put an ammeter in the power line.

Slew west at full speed, watch the current. Then slew east at full speed and watch the current.

The system is balanced when the current in both directions is as identical as possible.

#18 Ravenous

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Posted 21 August 2013 - 07:25 AM

One other thing it could be, is high-frequency vibration in the motor coils caused by the motor driver. If it drives them with PWM (pulse width modulation).

If so, it's nothing to worry about. It's just the motor being driven by a full power signal that goes on and off hundreds or thousands of times per second, to reglate the power, and the motor coil vibrates at that frequency giving a high-sounding tone.

I just thought I'd mention this because I've heard it in amateur robotics, etc. It depends on the motor - possibly how tightly the coils are wired. This could be why one is affected and not the other.

By the way, you mention it happens only when slewing. Does it also happen when tracking, if you resist the motion (carefully!)? If so then I think this could be the PWM noise, as the power is increased to fight the resistance.

#19 HowardK

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Posted 21 August 2013 - 01:28 PM

Will check that next time out
Thanks for your input

#20 HowardK

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Posted 21 August 2013 - 03:33 PM

The binding type squeek only happens when performing a goto and this squeek happens in a specific part of the RA axis...about 45degrees in circumference...the rest of the axis is fine.

Does not happen when slewing at any rate...fast, slow or maximum rate 9...only binds when doing a goto.
Playing with the RA clutch has no effect.
I believe balance is good.

Any clues as to what is happening here?

#21 HowardK

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Posted 21 August 2013 - 05:53 PM

Problem fixed

It was a low voltage thing

12.4 volts and no squeek

Thanks Rod

One time you're going to be wrong about something.

#22 HowardK

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Posted 21 August 2013 - 05:55 PM

Wonder why it only occured when gotoing a target and not when

Tracking or slewing at any rate






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