Introduction: Small Wind Turbine Generator (ALEKO WG400) Evaluation, Upgrade and Controlled Test.
I recently got my ALEKO wg400 wind turbine generator. I had purchased it from Amazon.
I decided to open it up to evaluate how well engineered this generator is. The results were not good. For one, the generator is advertised as a 400watt unit however this is its maximum output. The nominal is 250watt. I decided to perform certain key upgrades and then do a basic home test of the generator.
Please note that ALEKO, GUDCRAFT and a few others are basically the SAME turbine manufacturer. The lessons learnt in this instructable will easily apply to those other brands.
Read on for what I did!
Step 1: Removing the Tail and Back Plate.
Simple Allen key screws to remove. The tail contains the dump load resistor. This is wired back into the housing at the back. The Silicone seal for the wires was not good. Also the back plate did not have a gasket for weatherproofing! Water ingress will happen with this unit if installed as is.
Step 2: Removing the Front.
Four screws for the front and you can see the permanent magnet alternator (pma). At least there is a gasket here. Bearing seems Ok.
Step 3: Inspecting the Windings.
The rotor needed a firm pull directly outwards to be removed. The magnets seem strong however they tend to slide in their slots which is not a good thing.
The stator windings were OK however one wire I found not well secured.
This pma is a totally enclosed non ventilated design. The cooling comes via the ribs along the outside of the enclosure.
The rear bearing seems Ok.
Step 4: The Charge Controller and Rectifier Removal.
The idea of having key electronics inside the pma I don't like. Besides, I bought an mppt charge controller just for this turbine and I don't want to use the oem. Removal was easy and I tossed the dump load resistor also. I have an even better dump load to use.
I believe the stock charge controller is the reason for the 250watt nominal rating on this generator. Using a higher watt controller should allow for more power out.
Step 5: Installing a New Rectifier.
I installed a 100amp 1000volt rated three phase rectifier. I had to trim two heatsink tabs in order for it to fit. I used silicone adhesive to secure the rectifier onto the enclosure. I soldered the 5 wires to the rectifier.
I noticed the quality of the crimp lugs on all the internal wires was terrible. The wires were corroded and definitely would have significant voltage drop.
In a possible future upgrade, I aim to remove the three phase rectifier from the turbine. I ideally want just 3 wires coming from the turbine back into my house. This method will allow me to rapidly replace a blown Rectifier and allow me perform insulation resistance testing plus low resistance testing of the pma windings. These tests are important to know if the health of the pma is degrading with time. A test voltage of 100volts dc should yield a minimum insulation resistance of 1megaohm. Each phase has a resistance of 1.64ohm (lower resistance will indicate an inter turn winding failure).
Step 6: Waterproofing the Enclosure.
Using silicone gasket maker I sealed up the back plate. The hole in the tail for the dump load resistor I sealed with black silicone adhesive.
Step 7: Lubricating the Key Components.
I used grease and applied a small amount to the spindle, the bearings inner race and the inside of the stator.
The reassembled turbine now spins much easier than oem.
The oem spin was very tough. It took a little torque to get it to turn. Now with the greased components it spins with my hand turn and continues to spin! I'm confident now that the wind will turn this pma easily.
I intend to remove the turbine every 6 months for scheduled lubrication in order to keep it producing power easily. My intended mounting height is at the roof where I can safely reach it.
Step 8: Blades Hub Wobble.
Here is another example of the poor engineering of this unit. Apparently the hex nut doesnt seat properly into the hub so while hand spinning it after tightening the nut, there was a nasty wobble on the rotor (almost as if the hub is slightly slanted due to the nut). I tried the hub without the nut and it spun perfectly (although without spinning the rotor) without any wobble. I dared not try to tap the nut into the cast aluminum hub for fear of breaking it.
If the turbine is allowed to operate with this wobble, the bearings will fail prematurely, there will be heavy vibration and noise, efficiency will drop severely and most importantly, I will be grumpy.
To fix this annoyance, I marked the side with the lowest wobble relative to the turbine body. I took the nut and filed approximately 0.5mm (yes that little bit!) off one side. The filed side I faced on the mark I made and reassembled the hub on the rotor. Now it spins near perfectly! Also I put grease on the side facing the turbine body.
ALEKO and GUDCRAFT, shame on you for producing these inconsistencies!
I feel more confident now that the turbine would do its job when I commission it.
Here is the video of the fixed hub.
Step 9: Testing the Reassembled Turbine at Home!
I used my Cordless drill and a socket to drive the spindle nut. On the lowest gear I got 22volt dc. On the highest gear I got 83volt dc. Wind turbine pma are typically wired in star and this explains so huge the difference in voltages for those rpm ranges. A delta connected winding simply cannot produce that high a voltage swing however both star and delta gives the same power for the same pma.
Basically I made sure the turbine works without having to wait until I commissioned the unit. In the coming weeks I aim to install it and then real world results will be available.
I did a follow up test, this time using the pma to charge my battery bank. I used a dc dc buck boost converter followed by an energy meter. The dc dc converter is actually my charge controller with an output voltage of 27v. On the low gear of my Cordless drill I got approximately 51watts out of the pma. At least I know for sure this pma can produce usable power.