Generac LP generator didn't start up when needed today

[grsthegreat]

4 pole generator is too large and heavy for an air cooled to handle



No idea what you mean here. A 4 pole motor or generator of the same kw is basically the same weight and size of a 2 pole version.

no it isnt. ive seen the 22kw 4 pole unit that generac makes and its way larger. have no idea whats inside it as to windings as ive never seen the insides of one of them. i have pulled the 2 pole stater and rotor apart. id like to be able to compare them. if they were the same we all would be using them instead of the 3600 rpm units.


i found this

A 4-pole motor has about 3.0 ft.-lbs of torque per horsepower where a 2-pole motor has 1.5 ft.-lbs of torque. At 60 Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm. a smaller motor running at 3600 rpm just doesnt have the torque needed to spin the larger rotor on the 4 pole unit. generac stated that the 4 pole stater has nearly twice the copper in the windings.

 

[CalG]

no it isnt. ive seen the 22kw 4 pole unit that generac makes and its way larger. have no idea whats inside it as to windings as ive never seen the insides of one of them. i have pulled the 2 pole stater and rotor apart. id like to be able to compare them. if they were the same we all would be using them instead of the 3600 rpm units.


i found this

A 4-pole motor has about 3.0 ft.-lbs of torque per horsepower where a 2-pole motor has 1.5 ft.-lbs of torque. At 60 Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm. a smaller motor running at 3600 rpm just doesnt have the torque needed to spin the larger rotor on the 4 pole unit. generac stated that the 4 pole stater has nearly twice the copper in the windings.

Those numbers make perfect sense...... Horsepower being calculated as Torque X RPM divided by constant (33,000 in many cases) ;-)

 

[zzvyb6]

Now if she had a tractor, would it have started, and would she have needed it to plow the snow, clear the driveway of twigs, or go and get the mail ?

 

[ray66v]

my service regimen is oil change every 2 years (mostly due to moisture build up in oil)

That's the problem with running 12 minutes every month. It runs long enough to warm up fully, and develop lots of condensation during cool down, but not long enough to evaporate much of it off.

 

[Rebeldad1]

Just back from "the service call". ;-)


I'm troubled about that ex valve. I think I'll double check that jamb nut next week after another exercise cycle. I didn't think to bring the never-seeze, the old plug threads looked dry, but the plugs screwed out by hand after loosening with the socket.


I would be very carefull using never sieze
Its ok on cast heads but not on aluminum. In the automotive world there has been several TSB'S stating so.
Had a customer who had a dead cylinder. replaced with cheap plugs and still had issues. Brought it into the shop and I started with removing the plugs for a compression check. They all barely moved. The more I tried the tighter they got. Customer said he didnt over tighten the plugs and used never sieze.

A good lesson learned. No never sieze on plugs and always used nickel plate plugs.

 

[grsthegreat]

are so many differing views about anti sieze snd aluminum block engines my head will spin. Ive been using it on my jet skis for 10 years without issue...the service manual even states to use it. During tech school we were told to use minute amounts on threads. Ive been doing so for many years without any issues. Plugs come out easy. Everyone has their own opinions. One thing is for sure, Ive never encountered a stuck plug on an aluminum head where anti sieze product was used. Never

 

[ray66v]

It is very common to use never seize for spark plugs, on aircraft aluminum engines.

 

[Industrial Toys]

Where does the exhaust go? Many generators I see make no provisions for diverting exhaust. I have seen stuff horribly jury rigged, being a fire hazzard. Another, the makeshift coupler came off inside a dog house, melting the air intake and frying the alternator from high temperature. Nice repair job for me though!

 

[CalG]

Where does the exhaust go? Many generators I see make no provisions for diverting exhaust. I have seen stuff horribly jury rigged, being a fire hazzard. Another, the makeshift coupler came off inside a dog house, melting the air intake and frying the alternator from high temperature. Nice repair job for me though!

Hmm

You bring up a good point.

By design, the exhaust leaves the muffler/tail pipe on the far side of a partition wall that is part of the total cabinet structure. The tail pipe is pretty well sealed from the engine/generator center section, and the tail pipe cavity is vented via a louvered section low on the far end of the cabinet.

The muffler it's self shares the cabinet center section along with the engine generator unit that includes the air cleaner box.

The combustion air intake to the air filter box is a pick off duct from the flywheel fan blades. A "first stage bleed" in the turbine world. The air inlet for the flywheel fan is on the far side of another internal partition wall that serves as a support for the control electricals and the space serves as the propane regulator housing and holds the starting battery.

If the engine exhaust were to empty into the center section, and find it's way into the fresh air intake section , which I assume runs at somewhat negative pressure due to the cooling fan suction, some mixing of the exhaust with the fresh intake air is likely. Uncontrolled EGR ;-)

I assume that the engine cooling air is vented outside the cabinet through louvers on the backside of the cabinet, but did not go behind the unit to see. I'll put this on my to do list.
Any issues this combination may cause is likely dependent on the free air passage between the internal partitions and also the outside to inside flow of air to the cabinet.

I'm pretty sure that new spark plugs did the most to remedy the failure to start. But if I can make things better for her, I'll try.

 

[Industrial Toys]

I was just kind of curious how and to where one exhausts a generator sitting in a barn. I have heard of numerous portable generators setting fire to buildings. One, very close to here.