Has my chipper come back down-rated?

[arbmark]

Evening all,

The engine on my chipper went kaput within warranty and the manufacturer has replaced it but they have adjusted the machine so that the rotor speed has dropped from 1900 to 1740rpm.

Now they are claiming that the 'throughput' is the same but I cant see how it can be - it certainly wouldn't throw the chip as far. They have raised the lower no stress limit and altered pulley lengths and ratios. I think they may have sped up the rollers but I cant be sure/remember.

I had a bigger model for the 3/4 weeks the chipper was away for repairs so I am trying not to compare it to that, but I am sure my machine was more impressive before. The machine returned gleaming with paintwork all restored which was awesome....and had new blades fitted - possibly to mask performance issues?!

I dont want to name the manufacturer in fairness yet but does their claim sound possible? Its beyond my mechanical brain to work out.

Cheers

Mark

[Mountain man]

You're going to have to tell us what machine it is.

[IVECOKID]

Probably set at peak torque band ,after that its just speed .

 

 

 

 

 

Ste

[Ian C]

Probably lowered max rpm to stop a second engine going pop. You will have to say what machine.

[Al Cormack]

Greenmech arb 130 according to previous posts.

[skyhuck]

Probably set at peak torque band ,after that its just speed .

 

 

 

 

 

Ste

 

Not sure its a simple as that.

 

As the OP states the lower speed will reduce draft, which if chipping wet conifer or privet could lead to a blocked shoot. Also less speed will reduce the inertia of the flywheel, the peak torque band will be hit once the chipper is under load, I don't think it wants to start there, because it will be very quickly pulled down below this as soon as its starts working hard.

[difflock]

Easy enough to compute if the changed pully ratios compensate for the reduced engine rpm.

Assuming you can get an origional engined machine to check the old pully dias.

then as said if the engine has the torque, possibly tweeked electronically on the new engine.

[arbmark]

Greenmech arb 130 according to previous posts.

 

Oh well there goes discretion.....! Greenmech have been really good all in all. I just don't think the machine is like it was.....which was awesome, sparky manoeuvrable and up to the job.....and i guess it still is now, but this rotor speed is nagging me.

[arbmark]

Not sure its a simple as that.

 

As the OP states the lower speed will reduce draft, which if chipping wet conifer or privet could lead to a blocked shoot. Also less speed will reduce the inertia of the flywheel, the peak torque band will be hit once the chipper is under load, I don't think it wants to start there, because it will be very quickly pulled down below this as soon as its starts working hard.

 

hence why the lower no-stress limit has been raised maybe? Agreed, the draft must be down. I don't even know if the engine speed is down on before as the box only displays rotor speed. They are really quiet machines.

[Ian C]

Why not call gm and ask them the why's and wots?