Dec 22, 2013

An attempt to fix the autopilot

N 28° 28.042', W 16° 14.639'

When I had slept enough I started to study our noisy autopilot. 

First I started reading manuals. Our system is quite new to me. Some stop cocks are transposed because of the lack of space, but my father-in-law's drawings were clear enough.

I tested the inside steering unit. I filled up the hydraulic liquid and released the air from the cylinder, after that it worked. However this didn't stop the banging.

I separated the pump and valve box from the motor. When running the motor the banging was still there. This was bad news, because the electric motor is probably the most expensive part of the whole system.

I was curios about what was causing the noise. I took the motor apart.

Bearings and brushes had nothing wrong with them and the coil seemed ok.

When I reassembled the motor I noticed that one of the four magnets was loose. It was glued to motor outer cover by magnetic force. Every time the motor changed direction it clashed to one of the bolts that were holding the pack together. 

There was some hope. By gluing the loose magnet back, the motor might work.

The loose magnet was the inner one, that was difficult to clean for gluing.

After the glue was fixed I trusted that the motor was ok and we had saved a thousand euros.

Luckily I didn't have time to spend that money. Motor started ok, but it was slow and started smoking. Smoke test failed!

At first when we got this problem, the hydraulic pump motor changed tune, before it started banging. It might be that the motor started heating and the heath caused the magnet's glue to soften and fail.

The motor has had moisture on it, because it was covered with thick rust.

Anyway we must order a new pump. (Or a drive unit as they call it.) Our current one is Robertson RPU150. The replacement is Simrad RPU160. (RPU = Robertson Pump Unit) 

We hope that Simrad has kept the good quality. Broken pump is now twenty years old.

Many brands have given up any quality at all. They are riding with the old brand and draining the money out for investors.

Well, I will write another blog about our new Lewmar windlass, when I get angry enough. That will be all about the quality.