mains vibration

[MartinB]

It's one problem after another at the moment. Just when I've got my IT problems sorted (stick with XP stupid!) another problem has reared it's ugly head. Last night the guiding was all over the shop, eventually I found that the whole rig was vibrating, probably mains frequency. Yuk!

My Lodestar died and my QSI 532 misted over. Apart from that it was just great:rolleyes:

I've tried to track down the source of the vibration. It is there with just the mount switched on but the powered USB hub seems to add to it. I'm presuming the source is from the power supplies. Is there anyway of cleaning up a DC power supply or is it just a matter of getting new power supplies? I'm pretty clueless with this electrical stuff.

[barkis]

Are all the affected Items in contact with mount Martin.

Also, is the mount hollow, or filled with a deadening agent, ie sand, or concrete. I think the mount might be amplifying what initially is minute resonance. Then again, I may be talking rubbish.

Ron.

[MartinB]

Ron, the pier isn't hollow but I have had this problem before when I was using a tripod but it went away. I had put it down to using a dodgy Ac to 12 V converter. If I run the mount off a battery pack there isn't a problem although I suspect some intermittent problems from other sources especially the powered usb hub. This is connecting to a the mount, the focuser, guide and main cameras.

[barkis]

Well, I hope you track the problem to a conclusion Martin.

I had a similar problem many years ago. My Equatorial mount was a home made GEM on an A Frame structure. The drive was driven by a mains synchronous motor, powered by a 12v dc Inverter.

Everything but the motor was out of direct contact with the mount itself, but that frequency built up over a matter of minutes, and destroyed a perfect focus. Merely touching the focuser with finger tips cleared it, only for it to re build after a short interval.

It was a real PITA.

Good luck with it, I hope it doesn't become a long job.

Ron.

[Ibbo!]

Hi Martin

I have had a word with John Rose and we suggest you try a 24v supply (I use 24v with my NJP) if you can

John has them also John he could also test you supply with an oscilloscope

cheers

Steve

[MartinB]

Thanks Steve, it is a 24v supply I'm using, the Temma2 junior is a real snail without that. Would be great to get it tested so I'll let John have a look.

[roundycat]

look out for earth loops. Try to get all the mains powered bits tied down to the same earth point in a kind of series chain, just like your hi fi.

Dennis

[arad85]

look out for earth loops. Try to get all the mains powered bits tied down to the same earth point in a kind of series chain, just like your hi fi.

Dennis

Don't you mean star connected earthing (each earth all connected to the same central earthing point. surely a series connected chain is where you get the earth loops from

[Glider]

Is the dc power supply rated to supply enough current.

[MartinB]

Is the dc power supply rated to supply enough current.

I think so Glider but I'll have to double check. The old power supply packed in. I got 2 when I purchased the mount from Trutek although this one appears slightly different. Could that cause the vibration problem?

[astromerlin]

If your power supply is powered by the mains, check the DC smoothing capacitor isn't faulty. The only way to do this is to check with a scope or get a spare and connect across the DC supply.