After restoring the PCBs and implanting LEDs in the RPM trimmer panel it was time to rebuild the DC motor of the Beogram 4004 (5526) that I am restoring right now.
The first step is to extract the motor:
Then a complete disassembly allows getting to the bearings:
The bearings are the two small donuts up front center. Immersing them into motor oil and pulling a vacuum draws out the air that is in the pores of the oil-depleted Oilite brass bearing material:
Every air bubble that leaves the bearings enables an equal volume of oil to enter and replenish the bearing. After about 12-to-24 hrs the process usually stops and the bubbling ends, indicating that the bearing is full of oil again. Then the motor can be reassembled and a RPM test performed. I usually do this with the BeoloverRPM device that I developed a while ago. It allows logging the RPM every few sec and it transmits the measurement via its serial port to a connected computer where the RPM can be graphed against time. This shows the result of a 24 hrs run of this motor inserted into its Beogram 4004:
This is as stable as these DC motors get. The small fluctuations are a result of the analog control system reacting to temperature fluctuations and other external influences.
Im interested of your motor experiment.
ReplyDeleteVery interesting..
can you emai to me a several graphic data of measurement?. thank's