This is part of the process in a typical rebuild on the Bosch Travel Power alternator. A new slipring is epoxied and then soldered on. An engineering firm turns the slipring down so it’s perfectly straight. New bearings are fitted and the rotor is re-magnetised. I have rotors rebuilt to this stage so a generator can be turned around more quickly. It’s not always necessary to replace a slipring – some tend to wear more than others. Only high quality parts are used.
It’s important a travel power alternator is serviced from time to time as it’s possible bearing failure can destroy an alternator. The rear bearings tend to fail more frequently than the front. If there’s any play or roughness bearings should be changed.
The earlier Bosch alternator is a re worked low voltage unit popular in the 70’s and 80’s and was never designed to run a poly-V belt system. It’s very easy for owners and engineers to over tension the belt which can lead to premature failure.
Beta Marine fitted soft aluminum alternator pulleys and often these wear and loose their poly v profile leading to belt slip and over tensioning. I have smaller 50mm freewheeling pulleys which run dramatically smoother than a fixed pulley, increase belt grip and lower the level of belt tension required.