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Monday, May 19, 2014

Bio Dynamic 500 Mixer

Our mixing machine for BD 500 burnt out its motor last year.

BD 500 Mixer

We had a spare few motors just lying around. Some were well used items retrieved from a defunct dairy and one was the motor on our 1920's reconstituted milking machine. The milking machine has remained idle for nearly 20 years since we stopped breeding. It has a very good motor bought especially for the job and expensive.

Well it was time to bite the bullet and get the mixer functioning for next week.

At first I examined the old dairy motors to see if any were strong enough for this job. There was one that looked reasonable but the support brackets were badly rusted. An hour or two later the casing brackets were replaced with those from another motor. But the testing showed the motor was still not as good as preferred.

The non functioning motor

Some cut and shunt spares

And so it was a trip down to our hayshed where we had set up the milking machine and the newer motor was removed.

The biggest problem is the wiring. Not as simple as two wires. There are 5 wires to connect. One of which is Earth. That leaves 4. The complication is because the mixer turns one way creating a vortex and then stops and turns the other creating chaos.

Examining the connections

I was thinking that it would be as simple as lining up the wires on the old motor with the wires on the new. But not so. The new motor has a completely different setup. Well at least it looks completely different. I know from vague memories a theory that the basic operation is the same and that it just looks different.

The replacement motor

There was a small hope that the internet may supply some answers. Lots of forums on motors and reversing etc. but nothing that gave me any viable solution.

I set up a test bed near the mixer with electrical power and ran a series of tests. It was easy to make the motor go one way or the other but how to make it change direction using the mixer?

After lots of playing and thinking I eventually tried a test that worked. Who needs Sudoku or Crossword Puzzles. After installing the motor and testing the forward and backward operation I called it quits. Will test the mixer under full load next week. Oh and I also gave all the bearings a grease.


  1. Always interesting articles on your blog, but what is a Bio Dynamic 500 mixer for. What are you mixing?

    1. In Bio Dynamics there is a product called 500 which is made with cow manure stored in cow horns over Winter. 500 is a soil conditioner and needs to be mixed with water before it is sprayed on the soil In a particular way. A 500 mixer stirs the 500 in water. Firstly stirring one way and then another. A vortex is created during the stirring and then the sudden change in direction creates chaos before forming a vortex rotating in the opposite direction. That is the simplified answer and there is a lot more detail in terms of type of cow horns, manner of burial and storage and treatment of water, spray droplet size, materials used in equipment and timing of applications. The detail on 500 covers many pages so I've tried to just give the essence.