David Brown tachometer

[simonm]

Trying to understand this tachometer on my david brown 990, i can see where to set the engine revs for pto speed of 540 & 1000, but i need it to be set at 350 rpm

[Craig.]

About 1200 rpm or a smidge under in low range PTO, will be about 350rpm on shaft.

[simonm]

How do you work that out?

[C.J]

1166 for 540 shaft

700 for 1000 shaft

 

So if your tickover is say 850,PTO will be 425 rpm on the 1000 shaft.

 

Plenty enough power for your new log saw - good for fuel economy but bad for the engine.

 

If you want to run a hydraulic log splitter at the same time use 540 for better oil flow.

[IVECOKID]

1000rpm high speed low torque

 

540 rpm low speed high torque

 

 

Ste

[C.J]

  simonm said:

How do you work that out?

 

540 is at 1800 engine speed .

 

so 1 revolution for 3.3333 engine revs.

 

therefore 350 x 3.333 is at 1166

[Craig.]

Engine 1800rpm to give 540rpm on shaft,

engine 3.33 turns to 1 turn of shaft, (1800 divide by 540)

350 x 3.33 = 1165.5

1165.5 rpm = smidge under 1200rpm:thumbup:

[simonm]

I would never of worked that out last time i ran a pto was on a big john deere and was all digital.

 

I see most saws run at 540, why is this 350? just geared differently?

[IVECOKID]

  simonm said:

I would never of worked that out last time i ran a pto was on a big john deere and was all digital.

 

I see most saws run at 540, why is this 350? just geared differently?

 

Possibly the size of the saw, I noticed on my Balfor if I run at 540 the is a hint of speed wobble on the blade ,back off to 350 its bang on.

 

 

Ste

[simonm]

  IVECOKID said:

Possibly the size of the saw, I noticed on my Balfor if I run at 540 the is a hint of speed wobble on the blade ,back off to 350 its bang on.

 

 

Ste

 

Strange that because apparently they are both the same saw just different colours!