Lister Engines > Lister Based Generators

custom ST generator heads.

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n2toh:
If we can get new rotors wound with the extra poles the generators can be direct driven, I think that this configuration is more reliable than belt driven installations.

EDIT I should have clarified the direct drive generators are intended to be driven by a 2 cylinder engine.

quinnf:
   :o  The inertial loads imparted by a one-lung diesel on a direct driven generator rotor would tear it apart.  Belt drive is really not a bad compromise.

Quinn

EDIT:  Same difference on a two cylinder.  You've got a power stroke, then another 180 degrees later, then the engine coasts (slows down) for another 540 degrees (a turn and a half) then another power stroke, followed 180 degrees later by another.  This is not a friendly engine to directly couple to. 

Actually, go out and find ANY diesel that is direct coupled to a generator.  I bet there aren't any.  Perhaps you could use a flexible rubber coupler, but from what George has on his site regarding the mighty Changfas he has done that with, they tend to mash the rubber couplers in short order. 

The belt we're talking about here is a flat serpentine belt, not a V-belt.  They are very efficient, and that efficiency is the primary reason car companies no longer use v-belts on new designs. 

I don't want to belabor the point, but . . . well it looks like I am doing just that!   :P

hotater:
I agree with Quinn,  the belt takes up some of the firing impulse stresses and keeps stress off the rotor AND the connection between the two..  I've got 3400 hours on my first serp belt and I don't see a problem with that many more.

RobD:
I think the operative word in n2toh's post is that they "can" be direct driven. That does not mean that they "have" to. These units "can" also be belt driven, with any engine, all you have to do is match engine RPMs to Genhead RPM with the appropriate pulleys. It has been many years (25+) since I did motor theory in skool but what I can remember is that the more poles you have the smoother the power generation will be. I know that this is true with motors and I think that it is also true with generators. So from a smooth power perspective (think PC's and other electronics) this might be a good idea.

RobD.

trigzy:
"  The inertial loads imparted by a one-lung diesel on a direct driven generator rotor would tear it apart.  Belt drive is really not a bad compromise."

"Actually, go out and find ANY diesel that is direct coupled to a generator.  I bet there aren't any.  Perhaps you could use a flexible rubber coupler, but from what George has on his site regarding the mighty Changfas he has done that with, they tend to mash the rubber couplers in short order. "

A couple comments regarding these points, just for clarification:

I sell 3600RPM single cylinder diesel gens that direct coupled.  I have yet to have one "tear" apart on me, and some units have over 1500hrs on the meter.  (Surprising, given that they are chinese, I wasn't really expecting that much life out of them)

Large commerically produced generators 15+ KVA are all direct coupled, some (expecially the larger ones) without a rubber coupling.  There is just no easy way to move dozens to hundreds of horsepower without creating extra heat/losses and using up a tonne of space.

Granted, these units are all precision made, and aligned at factories, and it's probably not as practical for a lister, but it is probably much more widely used in reality than our serp belts.

Steve

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