Friday, 19 October 2012

Aerogen 4 service ideas, tips and tricks

The Aerogen 4 12 volts DC wind charger I have came off another boat, the previous owner  wanted a more powerfull type and sold his on to help fund the new ones. His boats system was on 24 volts, so I needed a new 12 volt stator ( 24v stator for sale!) The bearings needed replacing and the 316 stainless main shaft was frozen solid to the alloy hub. I had to make a special wooden jig to support the main body, we then used a friends hydraulic press to free the 15mm diameter shaft.



That was ten years back, time moves on and parts age, I decided on a new set of blades plus the center hub they fit into, parts were ex stock from the agents. With new bearings (four) fitted the Aerogen was refitted but it would not work, why? read on.

For some reason the blades did not turn as fast as they should, finding they were fitted the wrong way around (anything is possible) and even when fitted the right way, thats with the hollow side of the blade facing forwards, it still made little difference.

Note, those new blades have location marks on both sides!

I waited for an eventual gale, then checked the blades spinning, around 40 knots and they went quite well! I then checked for heat on the main body, it was as I suspected warm.
Note, during this test the wires to the battery were not connected, this was so I could use a voltage meter to check the output, there was none but there was load, why?

I removed the unit and took it back to the workshop, on the bench and with a copy of the service manual I could do the job much better. The manual gives all the checks possible step by step, I suspected the voltage rectifier which changes AC to DC.



Left click on the meter, you will see the needle shows an output.

What I found was with the meter on the disconnected terminals I was seeing an output on the meter but when they were reconnected to the rectifier no power came out of the two wires which would connect to the ships batteries. there was something else too, with the three center terminals off, the center shaft was quite free but when they were refitted the shaft loaded up, again, why?



What I found is not in the service manual!

Check the copper slip rings and the marks from the two brushes, the left hand brush was only just sitting on the left hand slip ring and the right hand brush was doing the same!

This of course was a dead short, I had found my problem but could not understand why or how it had happened?



The drawing in the manual shows the slip rings sitting higher up the shaft, if that was the case they would then sit correct to the carbon brushes, I could not get the center shaft to move higher, so had to do a total strip down to see what I could do with the slip rings when removed from the main unit. I found that the slip rings are supported in a plastic housing, using a vice,so some proper support, I was then able to use a steel drift on the 316 stainless shaft and knock the slip rings higher up the shaft, I saw no locking device such as a grub screw, it seems the assembly is an interference fit?



This is the Stator when removed.


Re assembly needs care, the stator is a loose fit but not by much, I used a little Fluid Film as
 a lubricant ( just a smear)



There are four washers and screws to hold the stator in place, I used silicone to cover them and ensure they do not come loose.



Now fully assembled and this time bench tested for a 12 volt output, with one hand spinning the shaft I see around 5 volts, with a friction pad and an electric drill, I see 15 volts, so we are free to go again!

Note, use a 20 amp fuse when you connect one of these chargers.

Roy


Aerogen 4 and the birds, left click the pictures for a larger view.

24 hours later and we have a south west gale brewing, some poor town in the Eastern Cape has seen 237mm of rain in the period! The Aerogen 4 looks to be doing its job, the batteries being at 12.8 volts, thats ok when a small DC fridge works 24/7 as well.

Note, we can service your wind charger if your prepared to handle the collection and delivery fees, plus the parts and labour. We are also hoping to offer a well established wind charger range in the near future.

Ask for details or keep watching this blog!


The blades are tied off in this picture so I can service it.

The news now is that the Aerogen 4 wind charger is back in service, the SE winds are strong and with a 60 watt solar panel as well, we have power to spare! The regulator is dumping power into the heat sink very nicely and even with lights and systems switched on we have fully charged batteries.

With power to spare the regulator and dump resistor is required.

There is a small trim pot at the rear of the black regulator,set from 11.5 volts to 17 volts, on mine and factory set, I see around 14 volts from the red output wires, one re output wire is for a single battery (two together are seen as one) or two output wires for duel battery banks. The regulator sees both banks differently and will allow charge to either until they are fully charged.

When this happens the green dump resistor takes the extra load and gets warm, then hot, it will start to make a small squeal, so you now when this is happening, you may as well stop the Aerogen then?


Wind power, its the way to go!

Reversed Polarity? a special feature blog on this subject is to follow, what it is and how to handle it.

Roy