A week on the tools - including a nice little job with a puzzle for you

[Lucien Nunes]

Time to unveil the new starter in operation. In the starter itself to the very left we have the timer, which I set to make the transition a little later than the pneumatic one was set, so that the blower is very nearly at full speed and the current a few amps lower when it happens. Then there is the overload relay, in the delta loop so set at FLC/sqrt(3) or about 4.5A for a 7.7A FLC. Then the line contactor, with the start button mounted on top, the delta and star contactors with a dual N/C interlock contact mounted across them (there's a mechanical interlock hidden inside too) and the isolator. In the box above is the monitoring relay and the auxiliary supply contactor slaved off the line contactor. The two sets of three brown 2.5's at the bottom are the two ends of the windings.

When you press the start button, provided the monitoring relay and O/L are normal, you start the timer which outputs a feed to the star contactor coil. This operates and its aux contact extends the feed to the line contactor which also operates, holds via one aux contact and bypasses the star aux with another. This sequence, rather than making the line contactor hold directly, proves that the delta is out before anything can happen, as an operated delta would prevent the star operating both electrically and mechanically. When the time elapses the star coil is de-energised, releasing the interlock and allowing the delta to operate.

Music next...

 

[Lucien Nunes]

And here's the result, including a brief musical demo, which reveals the console and its location. Don't play this through a tinny phone speaker, try it on the computer with the real speakers on. It's only a mobile phone video but you need a bit of bass to get the proper effect.

One day I will make a video of how all the organ electrics work...

 

[freddo]

Nice write-up, I still prefer the old version though...

 

[Lucien Nunes]

NB for anyone who hasn't spotted there's a brief musical demo in the video above^^.

Me too Freddo, but there were issues that needed addressing such as disintegrating rubber parts, difficulty of integrating a retrofit thermal O/L (it originally had none) etc meant that the starter would have to be considerably reworked if it were to remain in use. We preferred to conserve it for posterity rather than tinker with it and still possibly not have an ideal solution. Organs are expensive enough to maintain and if, like this one, they are only heard occasionally, one does not want an avoidable technical hitch to render the whole thing unplayable at a critical moment.

OTOH, amongst the old starters still at work in our sightlines there's a similar unit by the same makers that we don't plan to replace any time soon. It's the version for wound-rotor motors that puts the stator DOL but cuts out the rotor resistance in a couple of steps with rising pressure. This is on the much larger blower feeding the 1936/7 Southampton Guildhall Compton, one of the largest instruments of its type in the UK with two 4-manual consoles controlling 50 ranks of pipes (the Wurlitzer in this thread has 8). The motor is 17.5hp, 24A line at 400V, with a 3-phase 212V 38A rotor.

 

[DPG]

Very nice. Didn't realise the motors were so big for these things.

 

[SparkyChick]

They need to be, they can use huge volumes of air.

Pipe organs are just awesome pieces of engineering, and working on them was one of the best things I've ever done. Removing an old tracker (I think that's the right term for a purely mechanical linkage from console to wind chest) was one of the saddest, but many of the larger pipes got a new life as a pedal rank for a small village church organ so it wasn't all bad.

 

[Lucien Nunes]

These organs, designed to play music of many genres, have a lot of orchestrally voiced stops over and above the 'traditional' organ tones, some of which require mugh higher wind pressures. They also use what is termed 'extension', which allows each rank of pipes to do the work of two or three in a church organ by sounding more pipes per rank that the organist has fingers, so the wind volume consumed is higher as well as the pressure. A modest-size cinema organ therefore needs a blower more powerful than a very large church organ, which is more likely to be in the 3-5hp range. The very largest instruments sometimes have multiple blowers, the largest single blowers in the really colossal instruments are in the order of 100hp although these tend to be over-specced and rarely run anywhere near that load. Southampton is very well matched to its wind load and does perfectly with 17.5hp what a USA builder might have specced nearer 30hp.

 

[SparkyChick]

All I can say, is if you're ever in my part of the world working on one, I'd love to come along and take a look

 

[DPG]

All interesting stuff. There's a fairground museum on the east Yorkshire coast called 'The Scarborough Fair Collection'. They've got a few wagon mounted pipe organs there, along with various old fairground rides. Including a nice set of old dodgems. The good thing is most things are up and running and you can go on them which is nice. And they've got a working cakewalk. Some nice paintwork. Great place - worth a visit.
Of course, all you southerners will need a passport to visit yorkshire And I will personally check you over.

 

[SparkyChick]

Used to go to Scarborough on hols as a kid. Hire one of the beach huts for a week and try and ride the funicular near the Spa as many times as we could

Do Midlanders (with honorary Welsh status) require passports? I didn't the last time I went to Sheffield to see the fire service, but that was official business