Picked up half a megawatt worth of Caterpillar power, think I'll make a PTO generator

[crazyal]

A lot less efficient though. I don’t know about the lower maintenance parts either. Some truck transfer cases use chains and they’re practically zero maintenance. Some skid steers link the wheels together with chain and they don’t usually cause problems. Timing chains are less maintenance then timing belts. This piece will probably never get used enough to wear out chains. Belts will deteriorate faster.

Your talking about a chain bathed in oil. In this case it's not going to be which means it'll need some way to adjust the slack as it wears and it will require lubrication. With a genset of that size there's going to be a lot of momentum once it's up to speed. With a chain that could cause vibrations and when slowing it back down the tractor's pto will be acting like a brake so any adjuster for the chain will need to be able to handle that load. The chain could rust if left outside. A belt system will give up a slight bit of efficiency but the belt will last years without any maintenance. As the chain get dirty the efficiency gap is going to swing the other way.

 

[4570Man]

It might take a little work on the enclosure but is there any reason he can’t run an oil bath chain? Forklifts run greased chains in the lift and they don’t seem plagued with problems. A more accurate comparison might be a motorcycle chain.

 

[strantor]

Oil bath on the chain seems like a good call, and that's the plan for now. I've also been tossing around some belt ideas, not for the final drive, but for some sort of "pre-drive." Reason being, belts provide some inherent "clutch" action, which can be adjusted via belt tension. What was said earlier about the inertia of such a large rotor and the comparison to a starting up a large sawmill, has me a little concerned. I will have to make the determination once I get the rotor on two bearings and see how it behaves, but I might not want to simply flip the switch and engage the PTO with the rotor sitting at a dead standstill. Might burn up my PTO clutch? However if I can get the rotor up to 630rpm (190 PTO RPM), which is the slowest my PTO can turn (engine idle speed) before engaging the PTO clutch, that should be much gentler on my tractor. From there I can raise engine RPM to the appropriate value for 60Hz. I was thinking some kind of auxiliary motor (like a 12v automotive starter or similar series-wound motor) with a belt drive to the rotor which can be disengaged by relieving the belt tension. Maybe the starter motor could be positioned above the generator head so that when the belt hangs slack it does not ride against the pulley.

 

[redman135]

One thing nobody has mentioned, what quality of power will you get?
If it is smooth then all good. BUT if it is "lumpy" then expect electronics to play up, eg washing machine, computers etc. You may need to add a "conditioner" to "smooth" out the power.

 

[Agvg]

Suppose if he gets the rotor up to speed, the large mass of the rotor and the tiny amount of power he can take out will generate a very smooth Hz.

 

[radios1]

One thing nobody has mentioned, what quality of power will you get?
If it is smooth then all good. BUT if it is "lumpy" then expect electronics to play up, eg washing machine, computers etc. You may need to add a "conditioner" to "smooth" out the power.

a generator THAT large and expensive should be built properly, and provide clean power.. now, starting a rotor that large, especially with about a 3 to 1 speed increase is going to be very interesting. tripling the speed is going to triple the torque needed to start the rotor going..

 

[4570Man]

How hard does the generator head spin by hand compared to a rotary cutter? I think you’re over thinking the whole pre start idea. The generator head would have to outweigh the cutter blades by a significant amount to generate the same starting toque since it’s a lot smaller diameter.

 

[strantor]

How hard does the generator head spin by hand compared to a rotary cutter? I think you’re over thinking the whole pre start idea. The generator head would have to outweigh the cutter blades by a significant amount to generate the same starting toque since it’s a lot smaller diameter.

I don't know yet. The rotor is currently supported by a bearing on only one end. The other end is just free to flop around and sits inside, on the stator. I won't know how freely it spins until I come up with a 2nd bearing solution.

The whole generator head weighs 1800 lbs and I'm estimating 2/3 of that is stator, so if I'm right then the rotor weighs about 600lbs.

 

[chevy791979]

View attachment 575829
The above clutch would bolt on the engine.

The existing plate that's on the unit would have to replaced or retrofitted to accept the shaft from the clutch.

Twin disc brand makes PTO housings for about any engine

 

[radios1]

How hard does the generator head spin by hand compared to a rotary cutter? I think you’re over thinking the whole pre start idea. The generator head would have to outweigh the cutter blades by a significant amount to generate the same starting toque since it’s a lot smaller diameter.

take into account he wants to increase the speed(opposite a rotary cutter) so, a 3 to 1 speed increase will require 3x the torque.. it's like getting a tractor moving from a dead stop in high gear.. maybe a hydraulic pump/motor would better, you could slowly increase the speed by using the control valve.. if the pump had 3x the volume of the hydraulic motor, that should give you a 3x speed increase..