Blower pulley size

[Louis]

I am building a truckmount with a #4 blower, 22hp kohler, propane heat. I have a 5" pulley for the kohler. I was going to to put a smaller pulley on the blower so the engine can run a little slower since I am not getting heat from it

Am I asking for problems?

 

[Ron Werner]

larger sheave on the blower slows it down

 

[GeneMiller]

Most engines have a rpm that they run most efficient. I would shoot for that speed. If you run the engine to slow it will probably bog under load.

Gene

 

[Jay D]

Why not use a direct couple system. Motion Industries in Modesto has everything you need and its easier to set up. (at least for me)

 

[Ron Werner]

no, it won't bog down if you , is it over or under drive, the blower.
i had my big red set up as 1:1, and it bogged down because there wasnt enough power to drive it at that rpm. When I put a larger sheave on the blower, the engine was revved the same, but it took less power to drive the blower, basically it was easier. Like on a bike when you have a smaller gear at the pedals and a larger one on the wheel. She won't bog down.
Just run the engine at whatever speed is necessary for its optimum fuel efficiency, and then belt the blower accordingly.

 

[Louis]

The larger pulley is on the motor. I was told that the larger pulley should go on the motor.

The blower is on the bottom

I don't like couplers because if they break on a job you are done. Belts you are back in business in a hour or less. We only have guy that works on tm in the area and he is never there. I want to make the unit simple like a judsons.

What speed does most tm with a #4 turn at under load?


Thank You

 

[Johnny]

22hp is probably too small to run a #4 1:1. Might need to underdrive it a little (bigger pulley on blower).

 

[Bob Savage]

I have a slide-in with a Honda 24 HP engine, and a Roots #4 blower.

The Honda has an 8" pulley, and the Roots has a 7" pulley. I am "over-driving" the Roots for more CFM (dual wand truckmount), and the larger sheaves will give you more belt surface contact. I run a single "B" belt, MI belt tensioner, and usually get 1500+ hours easily out of one belt.

I have a tach/hour meter, so as I REV up the Honda, I can stop at whatever RPM I want the engine to turn. I assume your Kohler also has a hand operated throttle that can stop anywhere along the way.

If so, you already have control over operating RPM, so concentrate on whether you want the blower spinning faster than the engine RPM, or slower.

I usually run at 3000 Rpm's, and do NOT hear any bog when the machine is under load, using either single or dual wands.

 

[Jay D]

Overdrive it like BOBS. And it does'nt take but 20 minutes to change a coupler. :roll:

 

[frank]

I had a tm with direct couple system was a home made and only take me few minutes to change the couple like Jay said it had a 25 hp and a #45 and I dual wand a few times not always but was ease to change the couple.

 

[Louis]

when I rebuild my pto I might use a coupler but this one is belts for now. This setup was in a steamway frame before but it had the heater taken out. It was set up with a 1:1 on the old steamway but I was looking to get a little more out of the blower

Thank You

 

[Shane T]

I have an old unit that has a 23hrs engine & 45 Roots blower. It is direct coupled with a Dodge coupler. I can run it at 1500 rpm with no bog down if I want. Normaly I run it at about 2500rpm with a 14hg Kunkle and have very good vac. I have only replaced the coupler once in more than 25 years and that was my own fault.

 

[dgardner]

Louis, I looked up some numbers that may help. A Roots #45 pulls about 16hp at 16"hg and 3600 RPM. A Kohler Command 22hp motor makes 16hp at 2200 RPM according to the curve. If you have a 5" pulley on the motor, a 3" pulley on the blower will give you 3600 RPM with the Kohler turning 2200. The torque peak on the Kohler occurs at 2400 RPM, so bog will probably not be a problem.

Assuming you don't run full 16"hg, the lower hp will allow for the little bit the pump uses (the blower drops to 13.6hp at 14"hg). Bottom line is 3" is probably your lower limit. Like Bob says, you need a tach to make sure you don't over-rev the blower.

 

[Shane T]

Louis, I looked up some numbers that may help. A Roots #45 pulls about 16hp at 16"hg and 3600 RPM. A Kohler Command 22hp motor makes 16hp at 2200 RPM according to the curve. If you have a 5" pulley on the motor, a 3" pulley on the blower will give you 3600 RPM with the Kohler turning 2200.

Assuming you don't run full 16"hg, the lower hp will allow for the little bit the pump uses (the blower drops to 13.6hp at 14"hg). Bottom line is 3" is probably your lower limit.

A better setup may be a 7'' on the engine and a 5" on the blower.Larger or additional belts may be required when using such a small shive on the blower. There will be less surface area for the belts to grip and may cause slipping at higher hgs. Have someone spec the proper belts.

 

[dgardner]

A better setup may be a 7'' on the engine and a 5" on the blower.Larger or additional belts may be required when using such a small shive on the blower. There will be less surface area for the belts to grip and may cause slipping at higher hgs. Have someone spec the proper belts.

I agree, a 3" sheave will lower belt life some, but he said he already had a 5" for the engine. A 7"/5" combo would require an engine RPM of 2570 and would be better.

 

[Johnny]

My PowerClean Freedom is 4" on the 25hp water-cooled Kohler and 5.25 on the 47 Roots (under-driven blower).