Old field generator?

[TheReturnOfHightower]

Was at a county show today and they had this old beauty on display. Old field generator?

Anyway, thought some of you may appreciate me sharing it.

 

[Lucien Nunes]

It's to do with the genny, not the arc. It's 11pm, mid January 1943. Your detachment is posted to the back end of Little Muddington-on-the-Moor. Eight of you are on an exposed field, it's dark and cold, and there are no enemy aircraft over the UK. You haven't seen an aircraft all week. What now?

 

[DPG]

Make a brew.
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Is it something to do with the switching off of the searchlight, and it not being allowed to cool down too quickly?
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Ah, auto merge again. I wanted that as a separate bloody post!!!!
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Big arc lamps are sometimes water cooled. Is this relevant?

 

[Lucien Nunes]

Fine, so all of you have a brew, which doesn't involve anything electrical, and try to get a bit of kip. At 1 am, there's any number of flak gunners who can't see because your bl**dy beam's not in the sky. You're by the set, it's stiff and cold, you've knackered yourself and not yet got it over the first TDC. How many chaps are you going to have to drag off their posts to help you?

 

[marconi]

...

 

[Lucien Nunes]

Dynamo is quite able to keep itself warm (remember iron loss is as high off-load as on-load) but you haven't got the engine started yet. The call was a false alarm, nothing heading your way. Try to get back to sleep...

 

[DPG]

So it's to keep people warm then. Must be.

 

[Lucien Nunes]

Sorry that wasn't totally clear. See my edit. It's not people, not the dynamo and not the light (the heater is on board the trailer). Let's not always see the same hands.

 

[DPG]

So it's warming the area where the crew are.

Edit, forget that - you've already said it's not the people.

 

[davesparks]

Sorry that wasn't totally clear. See my edit. It's not people, not the dynamo and not the light (the heater is on board the trailer). Let's not always see the same hands.

That pretty much just leaves the engine, (unless it's the tyres on the trailer

So is it storing hot water to heat the engine and make it start easier?

 

[marconi]

I feel I am clutching at straws with this thought: The crew want to sleep but don't want the noise of the gennie keeping them awake but do want gennie to start quickly when required. It is hard work to start a cold engine. So after first cold start, you use an electric element to boil water to make steam which is then stored or used to compress air - (a diaphragm) between steam and air. When next engine start required crew can use the reservoir of pressurised air (or steam) to assist cranking up of engine....

 

[Lucien Nunes]

It powers an immersion heater to heat the cooling system. It works two ways; puts some load on the engine so the engine itself produces more heat, plus it heats the water in the jacket (the heater is in the return line from the rad and there's no thermostat so there's always full circulation; temp control is manual using louvres on the rad). While you're awake, start the set, run it for 20 mins to get it warm, then you can nod off again knowing the engine will not be such a pig to start when trouble shows up. Sleeping with it running is simply not an option!

Here's three of us starting my set using the 3-man start method, 2 on the handle (Gifford and myself) and Dan on decompressors. The immersion heater is in the housing bottom right of the rad at the very beginning. The guy in the greasy T-shirt at 0:29 adjusting the voltage is me.

Starting the 24kW set

 

[marconi]

Lucien: Is the Lister engine 'over-cooled' to stand high temperature climates then? An electric immersion heater powered by the dynamo turned by a diesel combustion engine to provide extra heating of its coolant and engine seems to me cack-handed; why not reduce the heat dissipation of the radiator, throttle the coolant flow or simply provide a blanket for a warmed engine?

Or was the IH to provide a convenient load for dynamo testing which became used in practice as you described?

 

[TheReturnOfHightower]

I tell you what mind, this thread has turned in to one of the most interesting threads on here - thank you to all for your input and enlightening me somewhat.
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[EricMark]

I have only worked on air cooled Listers, had a problem with traffic lights, the engines would carbon up rather quickly, found due to light load, cure was aluminium plate blocking part of the flywheel to cause it to run hotter.

So could see why if running without the search lights on, you would want to load the engine.