Is it a good idea

jimi

jimi

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to keep an invertor next to a fluxgate compass? Just dawned on me this is a possible cause of my autopilot not working .. ie continuous S's and circles .. is therea magnet inside an invertor?

<hr width=100% size=1>.. whit way roon should it be again ..
 
I would say the invertor is almost certainly causing you a problem particularly if you are driving your laptop through it, so it is live at the same time as autohelm.

I am sure there will be a transformer on the output side, which creates a considerable magnetic field in order to work.

I had a similar problem with the autohelm one day which I subsequently realised was due to stowing the dehumidifier and heater tube on the other side of the bulkhead to the compass. When I tested it at a later date, I was getting up to 60degrees variation!

Try removing the invertor, if its not too much work, and see what happens.

Good luck

<hr width=100% size=1>OK - Get Fell In you 'orrible lot! There's wine to be drunk!
 
What is running on the invertor, Chris? If it is switched off while you are sailing, you might be getting away with it, whereas I believe Jimi is using his for his laptop which means it is switched on at the same time as his autohelm.

<hr width=100% size=1>OK - Get Fell In you 'orrible lot! There's wine to be drunk!
 
Off and on, like Jimi, I use the inv for running my laptop for navigating, t'other half uses it for the hairdryer when we're piloting by mk1 eyeball.

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Invertor is "Switch Mode" operation so no transformers. Case is usually ally for heatsinking. Might be a low level high frequency interference from switching but shouldn't cause big problems. Proof of the pudding will be switching it off for a couple of cruises.

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An inverter is a Switch mode supply, but this doesn't mean it is devoid of transformers -it will still have a high freqency transformer, and probably a handfull of inductors as well, all of which will have a considerable magentic field.

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I did test the invertor with a handbearing compass,when it was switched off, and there did seem to be some magetic influnce from it even then. I had it stored within 6 inches of the fluxgate compass ... doh. Do'nt use the invertor for the laptop as I've wired the laptop straight into the boat's 12v system (old Toshiba).

<hr width=100% size=1>.. whit way roon should it be again ..
 
maybe you have two fluxgate compasses? Or two autopilots? Or an extra anchor dragging along spoiling things? It's worth a look. The invertor can't be affecting the autopilot because if it was you'd be upside down.

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Accepted. But with those inductances, I just didn't think it would amount to much field. Guess he has to try. Best to log the heading, switch the invertor on and read again?

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by robp on 26/01/2004 14:14 (server time).</FONT></P>
 
Will report back .. however to clarify. I'm not talking about it being switched on, just stored in an adjacent locker.. only thought about it last night when sorting something else so did'nt have a chance to test.

<hr width=100% size=1>.. whit way roon should it be again ..
 
Are you asking whether a fluxgate compass will be influenced by stray magnetism? If so the answer is yes, fluxgate compasses work by sensing magnetic fields. My inverter seems to have only a mild field when it is switched off ... a meter apart is recommended in the instructions.

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Terms like old/new ,good/bad, fat/thin, fast /slow are all relative to one's own particular perspective ..

<hr width=100% size=1>.. whit way roon should it be again ..
 
Yeah. But if its just metal, surely it would be consistant and not do 360's and S's? Mine's under the bed in the country cottage aft! Must get her to stow her handbag elswhere if that's the case!!

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Stick the invertor in a faraday cage, that should sort it.

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Inverter could affect fluxgate compass, depending on magfields generated, other possibility although you've probably checked it, is that it's set correctly for your boat

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