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.
I finished off the job after the original fitter fell out with the customer. The photo illustrates the adjusting arm used. I carry theses alternator adjusting arms with me in kit form with turn buckles, left and right hand stainless steel threaded bar, nuts, shims etc.. and good quality rod end bearings.
Called out to battery problems in Stone on a recently purchased narrowboat. Lucas A127 55amp alternator output poor and doing very little at tickover. Adverc ok. Tidy but badly installed system by well known and reputable boatyard (not in Stone) : cable sizes poor and Adverc battery sense fitted to common post of 1-2-both switch however long cable run (6mm cable/yellow crimps to domestic batteries) after the switch. Alternator pulley large. Fit a 90 amp marine alternator modified for Adverc. New long span laser cut curved adjusting arm, longer bolts, shims and 60mm custom XPA pulley. Gates Quadpower belt. All cable sizes including earth increased to 35mm and re-routed to shorter runs. Transformed alternator performance quickly jumping to 14.4V at low engine speeds.
The ST drives alternator at 1/2 speed off cam shaft alternator output is often poor at lower engine speeds. ST’s can often be improved relatively easily as the cam pulley is normally a reasonable size. I’ve fitted this alternator to 5 ST’s now with great results.
Call-out to Bollington to look at problems with a 4 cylinder Lister Alpha. Newly purchased narrowboat where the previous owner fitted the best equipment which looks good on paper. Smartgauge, Victron BMV, 2 large Victron AGM batteries, 24V 150A Mastervolt Alternator, Victron Multiplus etc.. Problem was with the ridiculously over spec’d Mastervolt alternator (like using a power station to supply a house). Mounting system was complicated and engine vibrations causing all the engine mounts and engine brackets to continuously work loose. This had been an ongoing problem. My solution was to fit a standard 60 amp 24V alternator with a smaller custom 65mm XPA pulley and single Gates Quadpower belt; Remove the 16mm charge leads (150A alternator!) and increase to 35mm due to lack of intelligent charging. Charging system is great and a match for the 220AH 24V battery bank. Engine runs smoothly and transforms the boat. Customers delighted.