Strange Motor symptoms

[smiffie]

We've been getting battered here all week by gale force winds. So I arrived home the other night only to find that I had no signal and when I attempted to move the dish it appeared to labour before an E2 error on the VBox, the dish had been left on 28E before I went out. It was dark at the time, but I could see that the dish appeared to be against the east limit so wondered if I could free it by moving it to the West, I could hear the motor moving?, pulses were being counted then the motor slowed down and stopped with an E2 error. But the dish did not appear to have moved!

Anyway I've had the chance to look at it today and the dish was indeed jammed fully east, I manually tried to push it towards the west, obviously it was locked by the gear box but there seems to be an unhealthy amount of play in the mount. It had the desired effect and I was able to step the dish away to the west. I noticed the mount had actually moved round the pole towards the west, which I thought a bit strange, but apart from that the dish and mount still seemed to be aligned so I moved to mount to the 0 position and locked up on 1 West.

The dish is following the arc fine but I've had to put in all the positions again as they were all over the place, there does seem to be a problem with the position repeatability with the some of the Eastern satellites. I'm wondering if there is some gearbox damage in that area of the arc as the motor speed varies and sometimes it appears to "labour", 28E is definetly the worst. I don't suspect the sensor as the pulses appear to be counting on the V Box.

Has anyone seen symptoms like this? If it is the gearbox can it be repaired? Its a Jaegar Silent Gold 99G H to H 36v.

 

[Topper]

Has anyone seen symptoms like this? If it is the gearbox can it be repaired? Its a Jaegar Silent Gold 99G H to H 36v.

Not on one of these but on other worm boxes yes, unfortunately what you describe is classic damaged teeth on a nylon crown wheel, to some extent it will continue working as the worm wheel is mounted tangentially to the crown wheel therefore there is contact with other teeth surfaces when the missing/damaged teeth mesh with the worm. The extent of the damage will determine how much the unit will slow or speed up and eventually the inevitable will happen. I have never seen spare part worm wheel assemblies for sale but knowing spares prices would expect it cheaper to replace the whole unit.

 

[space station]

Just take the plate of the gearbox,it is the plate where you wire upto the worm and gear should be visible to see any damage on the gears.

 

[smiffie]

Not on one of these but on other worm boxes yes, unfortunately what you describe is classic damaged teeth on a nylon crown wheel, to some extent it will continue working as the worm wheel is mounted tangentially to the crown wheel therefore there is contact with other teeth surfaces when the missing/damaged teeth mesh with the worm. The extent of the damage will determine how much the unit will slow or speed up and eventually the inevitable will happen. I have never seen spare part worm wheel assemblies for sale but knowing spares prices would expect it cheaper to replace the whole unit.

Thanks for the reply, since my post I've left the dish on 28E and now that the wind has whipped up the signal has dropped from 100% to about 50-60%, I'm convinced the gearbox has too much play in it to maintain the position. I think I'll just order another mount, its a shame as I only refurbished it about eighteen months ago with stainless steel fixings. I think I've had it since about 1997, so I guess it was due for replacing and perhaps its failure could be put down to normal wear and tear. Also I'll probably go down from a 100cm dish to an 85cm as my provider has moved from 16E to 23E so I no longer need the extra antenna gain.

 

[Lazarus]

Fifteen years is a good life.

It owes you nowt!

 

[smiffie]

Fifteen years is a good life.

It owes you nowt!

Agghhh Bar Humbung, I was hoping to get another fifteen years! To be honest when I was looking at it earlier, it looks in fantastic condition after the refurbishment with the paint job and stainless steel fixing. Its in for better condition than the brand new dish that went up with it at the sme time.

 

[wod]

if you still want to keep the 36volt system as you will already have the wiring in place why not replace the motor with a proper polar mount and actuator ?

gibertini do a polar mount that will fit a smaller dish if you are going to downsize.

gibertini 90cm dish with polar mount and inverto black ultra lnb would be a good replacement.

or keep a look out for a 2nd hand channel master setup that will last in the winds.

 

[smiffie]

Thanks, yes I'm definetly sticking with 36v as I'm not really a fan of Diseqc mainly because of the speed to be honest, I can get a direct replacement for this mount. I'm not exactly sure what the advanatge would be of moving to an polar + actuator as I understand that the actuators have nylon gears as does the larger 3" H to H SMR1224 I believe. I'm putting the failure down to wear and tear as its already survived many other storms over a fifteen year period, when I think back I've probably seen slight symptoms for a couple of months now and these gales have finally sorted it out.

The current dish is an ISS 105 (see link) and whilst it does a decent job I really don't like the build quality and its already showing far too much rust considering the time its been up. I've also had to add guy-wires to the LNB arm to stop it moving too much in the wind. I would like something slightly smaller and of better quality without loosing too much performance hopefully. I'd like to stick with a mesh dish as they seem to have less wind resistance and are more discreet which is important with this installation.

_http://www.issinternationalltd.com/products.htm

I've spotted this dish which is actually closer to a 95cm according to the overall dimensions. I still look at 5E occasionally and I've found that an 80cm just cannot bring it in, hopefully this would give me enough gain for North West England.

_http://www.worldwidesatellite.co.uk/online-store/dishes/technomate/technomate-97-cm-mesh-dish.htm

 

[smiffie]

It is a shame this has failed after the recent refurishment, you can see that the stainless steel bolts, new paint job and gusset repair from many years ago was still holding up well. The main gearbox shows no sign of wear but the main gear at the base of the rotating pole has shattered completly so I seem to have established the problem!

 

[Lazarus]

Ouch.

Any ideas how the damage occurred, or do you think it was just "fair wear & tear" along with end-of-life failure? Fifteen years use, IIRC.

Are you going to apply the "Trigger's Broom" approach?

 

[smiffie]

Ouch.

Any ideas how the damage occurred, or do you think it was just "fair wear & tear" along with end-of-life failure? Fifteen years use, IIRC.

Are you going to apply the "Trigger's Broom" approach?

As the inquest into this fatality continues, on close inspection I'm not entirely convinced its wear and tear as I was expected stripped teeth. The fact that the gear has shattered could point to excessive sideways load on the dish as we had in those gales last week.

 

[Lazarus]

But the case for the defence might suggest that such a venerable appliance may have been more likely to give up the ghost in the wake of such an onslaught?

Can you fix it, do you think?

What you need is some engineering jiggery-pokery from our good friend Prof. Vipersan.

 

[smiffie]

I was hoping to use the old mounting bracket on the new motor with the gussets as I consider this to be a bad single point failure area which the manufacturer still hasn't addressed but unfortunately the new housing is slightly larger so it won't fit. I was also thinking of reusing the stainless steel bolts but I've noticed that they have improved the bolts on the new motor from the old galvanised type to the yellow type which look a similar colour to anchor bolt fittings, I think they call them "Zinc and Yellow Passivated plated". What are peoples view on the best in terms of weather resilience SS or Yellow?

 

[smiffie]

But the case for the defence might suggest that such a venerable appliance may have been more likely to give up the ghost in the wake of such an onslaught?

Can you fix it, do you think?

What you need is some engineering jiggery-pokery from our good friend Prof. Vipersan.

Yes I'll have a go in slower time, but the prority is to get the new unit up. It will be a completely new install, I've worked out that I can get away with 12" standoff T and K's rather than the 18" painted and rusty one's that are up. I've got two sets of 12" galvanised so that I can fit them as K-K or K-T-K if you see what I mean.

 

[smiffie]

Ouch.
Are you going to apply the "Trigger's Broom" approach?

Ah, got yer now, "This broom has had 17 new heads and 14 new handles":-

O-Ha

_http://www.youtube.com/watch?v=pbha4XclSMU

Well this motor has only been painted twice, been welded together once and only had six replacement mounting bolts and if I get a new crown gear then it will be as good as new!