HELP!! neq6 motors stalling / have no torque! Please help.

[pshepp1890]

I really needs help asap guys please. I had small play in my RA worm gear so tweaked it and now no play. Problem now is the RA turns as normal, but has no torque as in, I can put 1 finger on the weight bar and it stops, makes a grinding noise.

looking at the motors with the side panel off and it's not gears slipping, it's the motor itself won't rotate. 

What could the problem be? I was looking at buying a skywatcher Quattro tomorrow as well. Please help!

[Peter Drew]

It's possible that the gears have been too tightly, there should always be a very small amount of backlash. Another cause could be insufficient power to the motor, I tried a different PSU recently that did not have enough output and my motor stalled with a grinding noise. You need about 2amps to cover slewing.

[ChrisLX200]

Yes it is tricky getting the clearance of worm>wormwheel just right, best to do this by 'feel' but that often means disconnecting the motor so you can turn the worm shaft with your fingers to check if can turn freely. You also need to check for binding all around the gear because any slight eccentricity in the wormgear will cause problems only in one position and not in others. As Peter said (above), there has to be some clearance between the gears or the friction will be very high - perhaps enough to stall the motor completely.

ChrisH

[pshepp1890]

Thank you guys so so so much for your quick replies. You have no idea how much it means to have people just a post away that are willing to help. 

So the ones I adjusted were the small screws right behind the RA clock. 

So if I have over tightened these 2 small screws, that could be the problem? I'm also using mains power so electricity isn't an issue. 

[ChrisLX200]

7 minutes ago, pshepp1890 said:

Thank you guys so so so much for your quick replies. You have no idea how much it means to have people just a post away that are willing to help. 

So the ones I adjusted were the small screws right behind the RA clock. 

So if I have over tightened these 2 small screws, that could be the problem? I'm also using mains power so electricity isn't an issue. 

It does sound like you have over-tightened something but without a photo it's difficult to say what    All these mounts are different but there will likely be other small gears in the drive chain (little spur gears probably) which again - must have a little clearance in order to work.

ChrisH

[pshepp1890]

il give it a go at loosening the small screws in a bit and see if that works. Thank you again so much for your help. 

Also I noticed that the 4 screws on the back of the motor itself where very loose. Do these need to be loose or tight? 

[ChrisLX200]

25 minutes ago, pshepp1890 said:

il give it a go at loosening the small screws in a bit and see if that works. Thank you again so much for your help. 

Also I noticed that the 4 screws on the back of the motor itself where very loose. Do these need to be loose or tight? 

I can think of no reason why those should be loose... so I would nip them up.

ChrisH

[pshepp1890]

heres a vid I just took. I loosened off the worm screws just to see if it was this but still has no torque. 

[pshepp1890]

These are the small screws I was referring to. 

[barrie greenwood]

ore than likely the power supply not supplying enough to run the motor what are you using

[pshepp1890]

This is my power supply that runs off the house mains

[Thalestris24]

Hi

It sounds to me like something is binding i.e. you've over-adjusted one or more of the adjustment screws. Best thing is to take a step back and methodically follow Astrobaby's excellent guide  No need to strip down! Just do the various adjustments.

Louise

[pshepp1890]

That's what I thought but I've totally loosened all the adjustment screws and tried it so that all the gears are effectively loose and it still does it.

il give it another go tonight and see what I come up with. 

[Peter Drew]

The mains transformer rating looks adequate but despite this it might not be supplying the stated output. Might be worth trying a 12v car battery for a comparison.

[Dbswales]

8 hours ago, Thalestris24 said:

Hi

It sounds to me like something is binding i.e. you've over-adjusted one or more of the adjustment screws. Best thing is to take a step back and methodically follow Astrobaby's excellent guide  No need to strip down! Just do the various adjustments.

Louise

This guide was fantastic when i stripped down my mount to check things over when i wasn't happy with it. I ended up getting a bit "too familiar" with the  whole affair if you know what i mean  but was good in that separate elements needed to be lubricated and taking it apart and putting it back together again was worthwhile. The worm gear adjustment section that Louise has highlighted above was a bit tricky but made all the difference. 

[Thalestris24]

4 hours ago, pshepp1890 said:

That's what I thought but I've totally loosened all the adjustment screws and tried it so that all the gears are effectively loose and it still does it.

il give it another go tonight and see what I come up with. 

I think that loosening all the screws is the wrong approach! You have to do everything step by step methodically. Your mains PSU should be ok but cross-check it with another or check the loaded output voltage with a meter. I presume everything worked before but went wrong at some stage?

Louise

 

[pshepp1890]

Everything was working fine. it must be the gears too tight somewhere. I think a stripdown following that guide is the only way forward. Il give it a go at the small adjustments firstly and see where that leads. Could the motors themself be pushed up against the receiving gear to tightly perhaps? 

[Thalestris24]

38 minutes ago, pshepp1890 said:

Everything was working fine. it must be the gears too tight somewhere. I think a stripdown following that guide is the only way forward. Il give it a go at the small adjustments firstly and see where that leads. Could the motors themself be pushed up against the receiving gear to tightly perhaps? 

There are motor gears and worm gears - either could be binding. Adjusting the worm is particularly critical - there's a fine line between running smoothly and binding!

[pshepp1890]

You would think something that cost over 900 inc a tripod would be problem free... lol

Im giving it a go at adjusting using Astro baby's guide today and hope it works. 

[Thalestris24]

1 hour ago, pshepp1890 said:

You would think something that cost over 900 inc a tripod would be problem free... lol

Im giving it a go at adjusting using Astro baby's guide today and hope it works. 

I'm afraid that's at the budget end of the mount market!

Louise

[pshepp1890]

When you look at the home observatory side yeah lol il had a tinker today and thought I'd see just what weight/pressure it stalls at.

so I put 1 of the 6kg counter weights at the end of the weight bar and just started to stall. Bear in mind nothing at the other end.

So is this right? Does that sound about right? Cheers everyone. 

[Thalestris24]

ps set your PHD2 graph y-scale to +/-16 arc secs or to +/-16 pixels. That might give you a better idea on how far the graph appears to deflect.

Louise

[pshepp1890]

So do you think it lifting 6kg sounds about right? 

[Thalestris24]

Oops! Sorry - my last post belongs to another thread! Dunno how that happened!

I've no idea how much the motors should be able to lift. Obviously, the mount would normally be more or less balanced and any imbalance would be <500g, I think

Louise

[pshepp1890]

That's what I thought, if it's balanced it shouldn't make a difference. 

Im one of these perfectionists that if it could do it before, I want it back to the same standard. I dont want a "it works so it will do" lol. 

Would anyone be kind enough to try it out on theirs for me? See if it is supposed to lift more than just 6kg?