Lister diesel genset info needed

[Robt.]

Picked up an old genset powered by a Lister 8CD diesel. The generator unit has no markings except the trademark shown, which I'm guessing is English Electric Co. Produces 115/230 apparently and is huge; 2 inch shaft and weighs at least 750 pounds. Can anyone ID this generator for sure? I have photos with the covers off if anyone would like to see them I'd be happy to email them. Need a few parts for the engine too...

[B.Sparks]

I don't have any specific information on your generator. And it's highly doubtful that anybody in the States is going to know much about it. About the best I can offer are a few educated guesses.

The general rule of thumb is to allow 2 hp per kW. The "8" in the "8CD" designation of the engine refers to it's power rating - 8 hp. So, the rating of the genset - if it was commercially produced - would probably be on the order of 4 to 5 kW.

That's not to say that the generator (itself) couldn't be rated higher than 4 or 5 kW. You could drive a 10 kW generator with a 1 hp engine if you wanted to. It will still only produce 500 watts (actually less, on account of the greater losses in the larger generator) but it could be done. If the set is a 'homebrew' it's entirely possible that the generator is not quite matched to the engine. The builder may have used whatever generator was available. If the set was commercially produced, the manufacturer going to be more careful about matching up the generator and engine.

The next step would be to verify if the generator is AC or DC. A look under the back cover would help. If you see *only* a slotted commutator the gen is DC. If the slotted commutator is paired up with 3 or 4 slip rings (some call them "collector" rings) the machine is AC.

If the machine is AC, the layout of the field pole bolts on its outside would indicate that it is a 4 pole unit. To yield 60 hZ, it would need to be driven at 1800 rpm. (If the set were made in England, it may have been rated at 50 hZ and driven at 1500 rpm.)

Then it would help to look at the means of voltage regulation. There may or may not be a voltage regulator.

As for the engine, the Lister website might be able to provide the build date of your engine if you know the serial number. Believe it or not, Lister may still have parts available. There are several companies in India that make clones of Lister "C" series diesels. You might be able to get some parts from distributors of these "Listeroids."

[Robt.]

B. Sparks, thank you very much for that information. I suspected it was a "homebrew". The previous owner said the lights used to 'go up' when the engine fired! True or not I don't know! I don't quite understand the principle of hp to KVA, but I assume that the amount of current being drawn will change the amount of hp needed to maintain RPMs?

Attached are some additional photos, I'd be interested to hear any comments on them. I had considered a Kato 12.5KVA head for this engine, which is about half the size of the generator shown, but it seems I need a larger engine for that too?

The only regulation I can see is one rheostat controlled by a knob on top of the box. The rheostat is damaged with some wires broken around the beginning of it's circumference.

I did get a manual and production date and original purchaser information from David Edgington at www.stationaryenginebooks.com in the UK. Lister-Petter (as they now are) say they do not have parts for the engine.

I would like to find out the output of this generator head and English Electric Co. (if my guess is right on the logo) no longer exists so my chances are slim there. The shaft is 1 & 7/8" dia. and the housing about 17" in diameter with welded 1/2" plate construction. Overall length about 31".

Thanks again!

[PhilD]

The generator head looks simular to the Chinese made ST 4 pole heads.

Utterpower has info on both lister engines and the ST type heads. Most likely you wil be able to find parts through that site. Your generator brushes look the same as mine.

The rheostat is for fine voltage regulation and is probably not needed as these type heads are self excited and thus are self regulating to a large extent.

The Utterpower site also has a manual (in pdf format) that can help get the head producing electricity again.

Hope this helps get things running.

PhilD

[B.Sparks]

"I don't quite understand the principle of hp to KVA, but I assume that the amount of current being drawn will change the amount of hp needed to maintain RPMs?"

That's correct. It's not just a matter of spinning the generator. It takes energy to make energy - there is no such thing as a free lunch! A generator actually 'produces' nothing. It converts energy from one form (mechanical) into another form (electrical.) The higher the current drawn from the generator, the more mechanical power must be applied to it. Adding electrical load to a generator will cause it to act like a brake on the engine.

Think of it as a sort of currency exchange. The conversion formula says that 746 watts represents the same amount of energy as one horsepower. But that's only in a perfect world. In reality, even the best designed and built generator has losses, both mechanical and electrical. (Using the currency exchange metaphor, imagine a bank charging 20 percent or so every time you exchange a Canadian dollar for an American greenback.) You won't get 746 watts for every hp. It will be more like 500 watts per hp.

You can belt up just about any size generator to your engine. In a perfect world the generator will only require as much mechanical energy in as it puts out in electrical energy. But, as I mentioned earlier, there are energy losses. The losses are somewhat proportional to the generator's rating, generators of this size are roughly 80% efficient. You can use a 12 kVA generator with the 8 hp engine but you'll still only get about 4 kW out of it. You'll actually get a little less power out of this set up, or burn a little more fuel, than if you used a 4 kW generator. (Going back to the currency exchange, imagine that you only need $100 but you exchange $1000 worth of currency, and pay the 20% fee on the $1000 instead of $100.)

It's late and I don't know if all that makes any sense or not...

It looks like your English Electric generator isn't quite as old as it seems to be. It's an AC machine. It doesn't have a slotted commutator. That indicates that it uses semiconductor diodes for excitation. That would date it to the late 1950's or later. I only noticed 2 slip rings which would indicate only 120 *or* 240 vAC output, not 120/240 vAC. If the generator was made in England it might be 240, as that's the standard househould over there.

Judging from the condition of the generator, it would be a good idea to have the insulation tested before firing it up.

[Robt.]

Thank you PhilD and again B.Sparks. That all makes perfect sense and I really appreciated getting the benefit of your knowledge! Assuming this unit was built for 240AC would it have been possible to draw 120AC from it, as the previous owner was apparently doing?

I've had a look at www.utterpower.com and it's a great site. Seems I'd better keep looking for a 2 cylinder Lister and belt my old Master Electric 3.5KVA unit up to this engine. On the other hand, I wonder how conservative the 8hp rating on the engine is; it swings two pretty massive 22"x3" solid flywheels at up to 1200 rpm...hard to believe it doesn't produce more real hp than that little 2 cylinder Honda that is rated at 13hp! Of course that "13hp" genset is only rated for 4000 watts and doesn't have much of a flywheel!

[Robt.]

Here's the inside of the box with the rheostat.

[Robt.]

Sorry, that photo is upside down.

[B.Sparks]

If your generator was wound for 240 volts, you can still set it up to put out 120 by selecting the right resistance range for the rheostat.

The little square silver colored thing with four wires, show in the upper right hand of the picture is a full wave bridge rectifier. This confirms what I suspected. The generator is a four pole (1800 rpm) AC machine.

If weight and size aren't an issue, and you want to take the time to clean the generator up, there is no reason that you can't use it. You could even install a voltage regulator if you wanted to.

Size-wise, the 3.5 kVA generator head would be a great match for this engine. The Lister is conservatively rated, so you could probably run it at a slower speed and still get enough hp. out of it. But, chance are, the 3.5 Master gen is a 2 pole machine that needs to run at 3600 rpm. You'd need a pretty 'steep' ratio to do that.

As for your Honda engine, that's a whole different animal. Hp is hp, and strange as it seems, the Honda does in fact make far more hp than that big 'ol Lister. But the Honda's peak hp is rated at 3600 (or higher) rpm. It can only make those 13 horses for a short time before it starts to melt down. Honda makes some of the best small engines in the world. But even if you take good care of the engine you'd be lucky to get 3 - 4 thousand hours of life out of it. The Lister can pound away at full power (or better) 24/7. These engines have been known to last hundreds of thousands of hours.

A little side story relating to engine lifespan. A friend of mine was a mechanic with a company that provides traffic control signs for road construction sites. Until about 5 years ago or so, the flashing arrows that indicate lane closures were powered by gensets. (They're now solar powered.) Temporary traffic signals were sometimes placed in remote locations (bridges and overpasses) and these were also powered by gensets. The company wanted to experiment, with the intention of cutting costs. Instead of buying $4000 diesel sets, they tried some throwaway $400 gas sets powered by aluminum bore "Breaks & Scrapem" engines. In continuous use, the diesels lasted, on average, 10,000 hours and could be rebuilt a few times. The gas sets lasted 300 hours. That's about 2 weeks! The diesel sets were far more reliable. They could be counted on to run without fail, all week, unattended, on a tank of fuel. The gas engines frequently stalled, and this nearly led to accidents and lawsuits.

[Robt.]

Very interesting! Thank you for sharing that. The Master is a big old unit and runs at 1800 rpm; it's been checked out and works well when driven at that speed. I'll take some photos and post them shortly. 3.5KVA is pretty minimal for a backup generator however, so I'm sort of stuck needing something in the 5-7.5 KVA range. This English Electric (?) unit would clean up well as you suggest, and with the aluminum covers & vents & big brass bolts would make a good display generator as it has a more antique look than most.

Someone has been tweaking the rheostat so much that they have worn through the wires, or else there was some kind of electrical problem that burned them, but since the damage is confined to the first inch or so of the circumference, I'm guessing it was just wear. Is there any easy way to determine the output of the generator, other than powering it up and using a meter?

Durability is an interesting subject. I wonder how much longer those diesel high speed units would have lasted with a toilet paper bypass filter keeping the oil clean to a sub-micron level. New oil is filtered to about 5 micron particulate I understand and long-running engines like that don't have the startup wear problem so it would be interesting to see difference really clean oil all the time would make.