Or could be for non motive power, lights/kitchen etc. could then be different voltage.

The main generator would produce a variable voltage up to about 600v depending on controller setting and speed. And it was DC. This is before switch mode converters. Not much use for auxilliaries. My money is on it being the exciter generator.

Yes, I did miss something – the battery supplies the start windings which are situated on each main generator on a Deltic loco. in order to start them. 2 engines, 2 main generators, 2 aux.
The battery also supplies the field for the aux generator.
There is no sophisticated electronics, no transistors or valves – all relays and contactors, just magic.

This is probably tosh, but I remember when I was tasked with teaching about them as part of a C & G motor mechanics course, 2 stroke Diesels have to be supercharged and this was usually achieved by fitting a Roots blower.  As a Deltic is a 2 stroke might it be that device in the photograph was used to ram air into the engine to get it started as well as generating electricity?

On 15 September 2024 at 10:33 Don Cox Said:

This is probably tosh, but I remember when I was tasked with teaching about them as part of a C & G motor mechanics course, 2 stroke Diesels have to be supercharged and this was usually achieved by fitting a Roots blower.  As a Deltic is a 2 stroke might it be that device in the photograph was used to ram air into the engine to get it started as well as generating electricity?

Good tosh I think Don, it has me convinced.

The device ringed in blue looks very much like a centrifugal blower to me, including a hefty air pipe passing over the main generator to the big diesel at the back.

Same blower type as this smaller example:

I think the drum like object ringed in red is the powerful electric motor needed to drive enough air into the engine.   Might be an auxiliary generator.

If it is a centrifugal blower, providing volume rather than pressure, then like as not it fed a Roots compressor on the engine, and that  super-charged the cylinders.

Pretty sure I got a good book on Deltics out of the library about 40 years ago.   I remember it damning the development process, which led to deltics gaining an instant reputation for poor reliability.   Later Deltics were better, but never good to have the customer find serious design problems that should have been obvious to the maker!  My memory is terrible, but I don’t recall the book going into the exact layout of the engine in locomotives or boats.   Anyone know what the book was,  proper hardback, not a pamphlet.

Dave

The blower, or two blowers on some models, was mechanically driven on the other end of the engine, looking like a very large compressor section of a turbocharger with the familiar snail shell shape.

The auxiliary generator in the position shown in the OP pic was driven off the phase gearing at that end of the engine, it put out (on some models, perhaps not all) 110 volts to power lights, controls etc and also acted as exciter for the main tractive generator. That blower shape on the end is most likely cooling air for the generator/exciter. It would blow a nice cooling breeze but not enough to aspirate all those cylinders at full chat. But maybe it did feed the main blowers through some missing ducting? I think you can see the intake trunking on the other end of the engine, large round pipe leading from the blower on the far end to lower nearside cylinder bank intake port area.

On 15 September 2024 at 12:42 Hopper Said:

…

The auxiliary generator in the position shown in the OP pic was driven off the phase gearing at that end of the engine, it put out (on some models, perhaps not all) 110 volts to power lights, controls etc and also acted as exciter for the main tractive generator.

Does hopper, or anyone else, have the technology and engine nous needed to label Greensands’ photo?    I see a big diesel on the right with, I believe, the cover off revealing one bank of 6 cylinders.  On the left is a big generator.  I don’t see anything I can positively identify as an auxiliary generator.   Might be me though, I’m not an expert!

Next photo doesn’t help  it’s a Naval Deltic with no generators at all!

That blower shape on the end is most likely cooling air for the generator/exciter. It would blow a nice cooling breeze but not enough to aspirate all those cylinders at full chat. …

That’s a big motor driving the fan though.  A 10HP motor will blow over 60,000 cubic feet of air per minute out of one.  That’s 1.7 million litres, and doing a guesstimate, guided by this website:

The Napier Deltic had a 5.125 in (130 mm) bore and a 7.25 in (184 mm) stroke (x2). This gave each cylinder a displacement of 299 cu in (4.9 L), and the 18-cylinder engine displaced 5,384 cu in (88.2 L) 

As 1.7 million / 88 is enough air to run the engine at 5900 rpm, I suggest a 10HP fan is more than capable of aspirating a deltic.  In fact 10HP is over the top, making it likely the fan motor is only 5 or 6 HP.

Happy to be shot down in flames!

Dave

Without checking the books I think you will find a locomotive diesel engine uses 1/3 of its peak output power just running the compressor – so maybe 1000hp.

So have a look at

Deltics in Retrospect – Part 1

Scroll down near the bottom and there is a cutaway drawing of the engine. The blower is at the opposite end to the generator with 3 outlets connected to the ports on the sides of the cylinder blocks. This is the loco, not the boat. If you’ve got a working design in the boat you wouldn’t redesign it without good reason. I’ll go for the blower on the end of the auxiliary generator being for cooling the main generator

On 15 September 2024 at 17:44 SillyOldDuffer Said:

On 15 September 2024 at 12:42 Hopper Said:

…

The auxiliary generator in the position shown in the OP pic was driven off the phase gearing at that end of the engine, it put out (on some models, perhaps not all) 110 volts to power lights, controls etc and also acted as exciter for the main tractive generator.

Does hopper, or anyone else, have the technology and engine nous needed to label Greensands’ photo?

Well, yeah. I made a living as a diesel fitter on and off for some years after doing a post-apprenticeship tech college course in which the famously bizarre Deltic was inevitably studied, although I never got to work on one. I did mostly diesel generator work on standby power generators used in various hospitals and power stations where I worked and main power at remote outback mining and construction sites etc. I’m no expert but familiar with the basics. Plenty of others who posted above have far more relevant experience and training.

On 16 September 2024 at 01:14 Hopper Said:

On 15 September 2024 at 17:44 SillyOldDuffer Said:

On 15 September 2024 at 12:42 Hopper Said:

…

The auxiliary generator in the position shown in the OP pic was driven off the phase gearing at that end of the engine, it put out (on some models, perhaps not all) 110 volts to power lights, controls etc and also acted as exciter for the main tractive generator.

Does hopper, or anyone else, have the technology and engine nous needed to label Greensands’ photo?

Well, yeah. I made a living as a diesel fitter on and off for some years …

I don’t doubt Hopper’s diesel qualifications – exactly what I’m looking for.    But Hopper hasn’t gone the next step and labelled Greensands’ photo, probably because he doesn’t have the technology – an image editor like Photoshop, gimp etc.

We can meet in the middle.   Deltic experts, on Greensands’ photo below what do you think items A to G are:

My guesses:

A: Centrifugal Fan
B: Electric Motor driving the centrifugal fan
C: Pipe driving air into the engine OR extracting exhaust.  Extracting seems unlikely, because exhaust goes to the other end of the engine.   I don’t know which way scavenging works – blow clean air in, or suck mucky air out.
D: Main Generator
E: Gearbox increasing RPM to drive the generator, attached to the engine’s phasing gearbox behind
F: cylinder head on the engine, cover removed.
G: Exhaust

There might be an H hidden at far right behind the engine.  If present, it’s the turbo-compressor.

The big unanswered question for me, is B an auxiliary generator or a fan motor?

Dave

A centrifugal fan for cooling main generator, hanging off the end of

B which is the auxiliary generator which is driven via whatever is inside the casing C from the gears which synchronise the 3 crankshafts

D is the main generator

F is the engine, which appears to have one of the covers off

G is one of the ducts leading from the blower at the extreme right hand end which can’t be seen in the picture, but is clearly shown in the link I posted earlier

Parachute on fire yet?