The Craftmans Shop > New from Old
Puma / Dorman 6LE / MacFarlane B46B / 110 kVA Generator Resurrection
awemawson:
Joe, the paint was from Bitec who feature on eBay:
http://www.ebaystores.co.uk/MDA-Bitec/Hamer-Finish-/_i.html?_fsub=25448221011&_sid=210466991&_trksid=p4634.c0.m322
Pete, sorry but no, no bits picked out in different colours, it's not a Fairground Ride :clap:
I decided to investigate the wiring for the upper instrument panel and associated current transformers that feed the main ammeter. As I altered the selector switch I realised something was badly amiss with it. It was so stiff that the plastic shaft was literally doing a 90 degree rotation before it clicked into it's next position. I think I've mentioned before that I'm not keen on these cam switches but obviously I was going to have to dig into it and see if it could be saved. I'd expected a squirt of switch cleaner / lubricant to fix it but it made no difference.
So I carefully documented all the wires to it, and multiple links fitted to it, before gingerly dismantling it. As it came apart it rapidly became obvious that getting it back together wasn't going to be simple as there were several forms of operating cam, and their phasing was individually set by positions on a spline that of course had been lost in the process of dismantling :bang:
I found the stiffness to be a general swelling of several of the plastic parts where operating cams passed though locators, but the main issue was the 'four click' main detente mechanism which resisted all attempts at freeing it up to a workable state.
So what to do :scratch:
Well I could ignore it and not fit the panel - most of it's features are incorporated in the Deep Sea control - but critically not the ammeter, and the Deep Sea unit only derives it's voltage display by calculation from one phase and neutral, whereas the panel measures phase to phase.
So I tested each bit of the panel, the ammeter and volt meter seem to work fine, as does the vibrating reed frequency meter, but the hours meter is making a dreadful racket although it is counting up.
I think the way forward is to make a new panel with just the Voltmeter and Ammeter and devise an alternative switching method. The ammeter is simple just needing a single pole four way switch. (3 phases and off.) The voltmeter is slightly more complicated, switching both sides of the meter to one of three combinations of phases without shorting phase to phase in the process. Presumably break before make switches are essential. I've not quite got my head around what is needed so any clever chaps are welcome to make suggestions!
John Rudd:
As you already have one voltmeter, why not just buy 2 more, and then directly wire them across all three phases? Maybe a bit of a faff having to cut a panel....
You can then see at a glance what each ph is doing without having to mess with a switch ( and the issues with the wiring? :zap: )
awemawson:
John that certainly is an option and might well be cheaper.
I've worked out that I need a two pole four position 'break before make' switch rated at 500 volts. (Switches far less than an amp)
BTW panel cut outs are a breeze with the CNC plasma table :clap:
John Rudd:
You could go even cheaper and just have a 240v lamp ph-n x3.....as a simple go-no-go phase indicator....all the voltmeters are going to show is any slight variance in phase voltage.... :zap:
Depends on how much work you want..... :lol:
The 3.6MW sets we had ( when I was working..), their control panels were not complicated but had enough instrumentation on them for monitoring.... The basics, Volts, Amps, Frequency.....Turbine Outlet Temp, then a nest of modules for control/sequencing on start-up and a seperate panel for excitation/ syncing....when not in island mode, we would sync them to the incoming site supply for excess power management or if there was a chance of supply failure( quite common )
awemawson:
Turns out Schneider do a pair of specific switches for these applications, and RS Components have them in stock so hopefully arriving in the morning :clap:
I'll now go and sweep the remains of the original switch into the dustbin and clear my desk :lol:
(not cheap but at least 'the right thing' ! )
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