- Joined
- Apr 16, 2024
- Messages
- 2
A while back forum member RandyM posted about a project where he hooked up a pressure washer pump to the PTO shaft of his tractor. (I'd link to it but I can't post links since my account is too new). I'm trying to do something similar, however I have a slightly larger tractor and slightly larger pump. I'm struggling with trying to figure out how to properly design the drivetrain.
Pump specs:
Flow: 5.6 GPM
Pressure: 3500 PSI
Speed: 1450 RPM
Power requirement: 13.4 EBHP (electric brake HP, i.e. actual power output after accounting for engine and transmission efficiency loses. Since my tractor's output is measured at the PTO itself and not just engine HP, I am assuming that this requirement can be directly compared to the specced PTO shaft output).
Shaft: 24mm, keyed, about 1 1/4" long
Tractor:
PTO output: 19.5 HP
Speed: 540 RPM
Shaft: 1 3/8", straight (I have a shaft on order that has a 6-spline connector on one end that will connect to a PTO shaft with a slip clutch. It will set in a couple of pillow blocks on a welded frame.)
So my gear ratio is 2.69. I should just pick a couple of gears close to this ratio along with the neccessary bushings. Where I'm struggling is trying to calculate the appropriate type of belt(s) because I've never built anything with this much power behind it. It seems like v-belts are out of the question, unless I use 3-4 of them in parallel (which sounds like a pain to maintain).
So I'm looking at cogged belts (like RandyM) used. I originally was considering a 1" H-type belt (1/2" pitch), but my research seems to show that it's borderline-to-insufficient, depending on which calculator or chart I use. So then I started looking at 3" wide XH belts (7/8" pitch). But the neccessary gears are insanely heavy and expensive ($800+ on ebay for a 11-13" gear that weighs over 50 lbs.) It is also hard to find bushings for some options that are smaller than 1 7/16".
Does anyone have any insights? Thank you.
Pump specs:
Flow: 5.6 GPM
Pressure: 3500 PSI
Speed: 1450 RPM
Power requirement: 13.4 EBHP (electric brake HP, i.e. actual power output after accounting for engine and transmission efficiency loses. Since my tractor's output is measured at the PTO itself and not just engine HP, I am assuming that this requirement can be directly compared to the specced PTO shaft output).
Shaft: 24mm, keyed, about 1 1/4" long
Tractor:
PTO output: 19.5 HP
Speed: 540 RPM
Shaft: 1 3/8", straight (I have a shaft on order that has a 6-spline connector on one end that will connect to a PTO shaft with a slip clutch. It will set in a couple of pillow blocks on a welded frame.)
So my gear ratio is 2.69. I should just pick a couple of gears close to this ratio along with the neccessary bushings. Where I'm struggling is trying to calculate the appropriate type of belt(s) because I've never built anything with this much power behind it. It seems like v-belts are out of the question, unless I use 3-4 of them in parallel (which sounds like a pain to maintain).
So I'm looking at cogged belts (like RandyM) used. I originally was considering a 1" H-type belt (1/2" pitch), but my research seems to show that it's borderline-to-insufficient, depending on which calculator or chart I use. So then I started looking at 3" wide XH belts (7/8" pitch). But the neccessary gears are insanely heavy and expensive ($800+ on ebay for a 11-13" gear that weighs over 50 lbs.) It is also hard to find bushings for some options that are smaller than 1 7/16".
Does anyone have any insights? Thank you.
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