Sirius Dome motor problem

[h0ughy]

la nina can go and get knotted:P :help: :question:. it has seen record rainfall, continual humidity and lots of dampness. i think this has lead to the failure on my dome motor. ill admit i haven't used the dome since a day of clearish skies back in December last year. it has cleared to see that bright thing in the sky today and i fired up the observatory. only to hear a dull click and no motor action in any direction from the dome. i tested and checked the battery and its all good. but the dome motor wont tick over. now for me it looks like a windscreen wiper motor, but then i am going blind. any constructive comments greatly accepted:thumbsup:

[mura_gadi]

Hello,

Normally, its clean and check all the terminals, check or try other fuses, try another power cable and/or power source.

Have you greased the tracks and tried to give it a nudge to see if its seized greater than the torque of the engine?

Does the control panel light up etc?

[AstroJunk]

Its always the battery. I know you've checked it, but if you can, swap it out with another anyway.

If it doesn't work, I was wrong - so what's new :rofl:

[h0ughy]

Yes did most of that but don't grease the track. Just silicone

[h0ughy]

Had full voltage when I tested it with a battery tester, but will have to get some alligator clips to test with another battery

[iborg]

Hi

A multimeter can measure the full expected voltage with no load, but, then drop very low when the load (the motor) actually draws power.

With the battery tester clipped to the battery, try running the motor. You may see a dramatic drop in voltage.


FYI - the same type of result can occur with a 24V power supply plugged into the mains.

Philip

[AdamJL]

^ yeah, this. When I tried to return a power supply to Jaycar once that wasn't giving me 12V in use, they tested it with a multimeter and said "it's fine"... I looked at them and said "you haven't put it under load, how do you know?"

They refunded me.

[raymo]

Before anything else put a multimeter directly onto the motor with it disconnected from its power source. and see if it is open circuited or short circuited, or neither, then you will at least know whether the motor is o.k. or not.
raymo

[h0ughy]

OK took the advice and pulled apart one of my UPS units as I didn't have a spare battery. It proved that the motor worked it was the battery. Thank goodness. Will get a new one today

[iborg]

Good news - sort of!


Philip

[h0ughy]

Yes, new battery installed and it functions. I don't understand how it really failed as its on trickle charge normally but stranger things happen to those that aren't looking for trouble

[Astronovice]

If it is the motor you can get replacements in Australia from ether:

http://www.weldtronic.com.au/wp-content/uploads/2017/03/Section-9_Spare-Parts.pdf

See Catalogue page 10 - Wire Feed Motors
It seems the same motor is used for automatic wire feeders on MIG welders.

Or at:

https://au.impexron.com/9901005_24_V-Australia_Sales_Price-OSLV_Italia-2877633-11503

Where, as you suspected it is listed as a wiper motor.

Hope this helps :)

Haha I was writing this as were posting that you had fixed the problem

[iborg]

Hi David


Just possibly, the constant trickle charge is the problem.


I was reading recently about batteries in USP's. Apparently, it is better to discharge the UPS battery once in a while, as otherwise it is not likely to last more than about 3 years.

[h0ughy]

Ordinarily it would be connected to a solar panel but given the weather for the past years I put a small trickle charger on it