• First day of work on the rusty crane

    felix de swaef • 03/12/2023 at 19:06 • 0 comments

    A first look at the electronics shows that luckily the whole electronics box seems to be well sealed.

    sadly just turning the power back on did not magically fix everything.

    I have quite limited experience in control systems. especially the relay based ones. I am from the generation that uses microcontrollers and plc's for the simplest stuff. So figuring this spaghetti board was quite the task.

    Electronics

    since the power to the whole site had changed and I had to figure out what this was supposed to run on.

    Opening the motor cable box I was quite surprised to find 6 wires heading to the control box and no bridge plates for the star/delta configuration. Later I realised this was done with relays. The timer relays which had confused me were for switching between star and delta to make the crane start more softly. 

    Now knowing what most relays did this gave me a way to manually force the motors to engage.

    little side note: An event taking place in a few weeks was interested in using the main bridge of the crane to suspend some stuff from. However this meant it had to be in the center of the space witch was currently not the case. This was the first main objective

    after a quite satisfying cluck ... nothing happened. well at least there was some life in there. the motors were humming but not moving even an inch.

    after assembling my tools and going back down, ready to end for the day we decided to check the wheels and bearings to see what was blocking everything. 

    After finding the bearings in perfect shape we decided to keep at it. I got the jack from my emergency kit in my car and managed to lift the crane of its rails just enough to attempt to spin the wheels.

    I gotta say : Volkswagen ,you guys make some sturdy jacks ! 

    smooth as butter

    the wheels were spinning perfectly, this was quite confusing because we now had no idea what was blocking the motors from spinning.

    back up on the catwalk I opened up the motor. removing the rear cap was quite easy however I couldn't pull it of the rotor. After twisting it in an attempt to pry it off we realised that the whole crane was moving. after some more prying it came of after doing the same on the other side we were ready to try powering it again. 

    the motors have a (quite ingenious) internal brake for when there off. This brake had gotten stuck on both motors.

    I tried pressing the relays again and I must have pressed the one for the wrong configuration by accident because it shot in to motion with a speed that can only be described as scary fast when you're sitting on an few tons of old rusty metal 8 meters in the air.

    The speed was however quite less impressive from the ground . 

    There is no way to describe the satisfaction from getting something like this back to life. The crane was moved in to place for the event and work will be resumed after it has taken place.