Do It Yourself : Desert Cooler - 8

Click Rebuilding Desert Cooler  for all related posts

Dear reader, Thanks for reading this series so far. Your feedback is deeply appreciated.

All the mechanical stuff is now in place. All we need is to wire it up. I am not that good at electrical stuff and was apprehensive that will my wiring work. I had saved the sticker from fan motor that provided the wiring diagram and after consulting some forums, proceeded to wire the thing up.

My brother had arranged a new front grill because previous grill was of no use owing to corrosion. This one is plastic so I feel it will last longer:

The switches are supposed to be fixed on the yellow panel.

The stuff that is supposed to fit there.

The panel came off by applying some pressure. That was the only way because it did not had any screws anywhere:

Panel came out by applying pressure

 Now next challenge was to make groves for switch and a hole for the rotary speed selector switch:

Speed selector switch. The hole should be large enough to let the threaded part through.

 Like everything else begins, this one also began from markings and measurements:

Step 1: Measure

Step 2: Mark

Next need was to go through that sheet and make a rectangular hole for the switch. I decided to erode the inner portion using a drill. It was supposed to be slow and patience requiring task. And it was:

Drill holes in the sheet to make way for some other tools

Not so accurate but good enough

The drill holes were supposed to be close enough. But when drill is placed too close, bit skidded off on its own path hence the haphazard holes that you can see above. A bench drill would have been a better tool.

The gaps in the holes were easy to snap using a wire cutter. The internal piece then came off leaving an irregular hole where there should be a rectangle to host the pump switch.

The star of the show. Newly purchased wire cutter. You have been seeing its actions in other posts as well.

I had to (painstakingly slowly) use a wooden file to make the way for the switch

Filing, filing, filing...

Taking shape...good!

Phew... took 10-15 min of filing to fix the edges to make way for the switch

Fitting the fan speed switch was pretty easy. Just a 11 mm hole and done. There were going to be quite a few wires and taping them together with an electrical insulation tape was not the most maintainable option. The tape gets hard over time and is difficult to remove. So I decided to fit a connector block for the wiring connections:

These are the connectors readily available at  electrical stores. No tapes and no loose connections!

Connector blocks come with holes and just fastening a couple of screws was enough. Of course had to drill holes first through the panel for screws to pass:

Connector fastened to the panel using screws from the front

Screws holding connector block are visible on the front (Right).

I was not convinced when I saw flimsy wires connected to the rotary switch promising me to bear the load of cooler fan. In normal conditions it is okay. But a year and two down the line it is going to be not so safe deal. Something had to be done about it. Again should be maintainable solution.

Thin wires connected to the switch with tiny soldering joints. I don't buy that!

While I was washing my car next day an idea that struck me had me rush to the nearest motor workshop. I hunted for some used wire from a broken electrical assembly and some wire connectors.

Used wires from a burnt tail light of xyz car. Who cares? Got it for free!

This is a wire connector. Got 4 of these for Rs 10 :-) (Click to enlarge)

The advantage of these connectors is that they are easy to connect to the wires and in my case, the cooler switch had color coded wires. So color coded connector wires allowed me to connect it to the switch without loosing the wiring scheme's pattern.

The wires are pretty thick and now I am convinced that they will not burn out from use or current drawn by cooler fan motor.

Also eliminated the solder joints from the switch. Now wire connectors are connected to the connector block. And connector end of the wires mates with the fan speed control switch. The other end of connector block will receive the wires from Fan Motor. Connections will be tight and no need of using tape insulation.

Connectors to Fan Switch, Connector block for receiving Fan wires.

The red and black wires lead to the water pumps. Switch will make r break the circuit (On / Off)

Taking the panel to assembly location.

In the image above, Red, Blue, and White are speeds of the cooler fan and Black is common. That means, to run the cooler at speed Red, I connect one wire to Red and Black receives the other from the wall outlet. Other two wires remain idle while Red is being used. 

The speed switch just switches between Red, Blue and White while Black is hard-wired to Neutral end of the wall outlet.

There is another Earth wire (green) in the wall outlet. It is to be connected to metal body of the appliance. The purpose of this wire is to protect the handler of the appliance from any short circuits. Click here to read how Earthing mechanism works.

Another connector for earth wire

Have to sand off the paint to expose metal for connecting the ground wire

All the connections are almost completed and I was apprehensive if all will work. So before assembly, I decided to test the electrical wiring. Set up and ad-hoc wiring to test the connections using fan at various speeds to see if it works. I was expecting fireworks now!!

Ready to test

All wired up

Ready, steady, Test!

Test Run: Succeeded!

That was first time cooler showed any signs of life. I did not cry though. He he :-)

Then came the remaining components, the Pumps, Filter for water, water supply hoses from Pumps to water distributors etc etc. All was fitted together with no effort at all. Hoses went perfectly in place and pump wiring was already waiting to receive electrical connections. Water filter was also a perfect fit.

Almost there

View from the top. Pumps and filter are visible. Hoses and electrical wires are also visible

Another view. Still on the floor.

About to be fired up. Waiting for water to be filled in the reservoir

View from the pumps towards the top. Click to enlarge.

Up and running!!

Water sprinkles naturally from the holes in drop pipes. Two holes can be seen at the tip of each finger. Click to enlarge.

 

A view from the inside of room. No splashes of water and no vibrations. Cooler fan is running at the moment

Finally, the cooler is online! Three weeks of work and about Rs 2500 later we have a brand new Desert cooler in place.

This series of posts had become talk of the day with my colleagues and some friends. Dear all, the wait is over now. So are your jokes on the project deadline which was extended from one weekend to almost three. happens! :-P

As of now, it cools pretty well and we no longer need to use air conditioners. The living room and adjacent bedrooms are cooled to a comfortable level by this machine. So much so that we have to sometimes avoid the airflow. Hopefully, the cost will be covered in 2-3 months of electrical expenses due to reduced use of Air Conditioner. Market price of similar cooler is more than Rs 8000. So it has been quite a deal and fun too.

A good metric could be to use a thermometer and measure the difference between outside and inside temperature with cooler running. Another point is to see if any faults crop up in due course of use.

To build your own desert cooler, feel free to follow the posts with label: Rebuilding Desert Cooler. Or look-up the blog archive section from 1st of May 2011 onwards. If you want to receive all future content from this blog in you inbox then just click here


Finally, thanks for reading these intensely uninteresting and long instructional posts and thanks for pondering upon the geeky calculations in some of my posts.

Should anyone need any help on such activities I am ready to join the fun!


Operation Desert Cooler hereby concludes with exit code 0 :-)

Good night!