Vbelt and Pulley Design

[cmn8226]

Hello folks,

I have a dual drive skid that are Vbelts. A compressor is driven by either a Electric Motor or a diesel engine. The compressor sits in between the electric motor and the diesel engine. All pulleys/sheaves are rotating counter-clockwise. Engine and motor both have clutches for disengangement.

1. Compressor has a Pulley of 11.75 PCD 4 grooves running at 1340rpm which is the critical speed.

2. Engine has a Pulley of 6.6 PCD 2 groove running at 2386rpm

3. Electric motor Pulley to be designed, (2 grooves) Maximum RPM of motor is 1500rpm

My question is,
1. is there a minimum center to center sheave distance that is common industry practice? The belts are SPB type (compressor is british) and the engine is B type. Hope these will fit fine on the pulley

Based on the electric motor rpm of 1500 I have a Pulley size of 10.5"PCD

 

[MikeHalloran]

My first call would be to my local belt supplier to find out which belt lengths they stock or can have in a day.





Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

Will you need more than 25 HP?
Is the sheave mounted directly on the motor crank?

 

[MikeHalloran]

Tmoose brought up a good point.

Once you have a preliminary pulley size, you need to calculate the belt pull forces, and check that each of the rotating components can deal with the radial load from the belt pull, and the moment from the belt location and the belt pull.

Electric motors, for one instance, are often equipped with smallish bearings that can't take much of a radial load, unless you special order a motor with larger bearings.

Similar concerns apply to the engine and to the compressor.



Mike Halloran
Pembroke Pines, FL, USA

 

[diskullman]

EPT power transmission has pullies that will use "B" belts or "5V"
5V belts have the same angle as SPB belts. Check their website for all information required.

Russell Giuliano

 

[starkopete]

Hi,
I seem to remember a rule of thumb that said the minimum center to center distance has to be twice the diameter of the larger pulley.

Thanks

 

[starkopete]

Hi,
Please disregard my erroneous rule of thumb above. I decided to do some checking (my memory isn't what it used to be) and found the link below. The second article should help with your question of distance between pulleys.

Thanks

http://icemeister.net/Articles/FYI/Belt_Length_Changes.pdf

 

[lukin1977]

yes, there is a minimun center to center distance and a maximun too

e: distance center to center
d1: effective diameter of pulley 1
d2: effective diameter of pulley 2

e>0,7(d1+d2)
e<2(d1+d2)

I´ve used this limits many times and worked very well

 

[MikeHalloran]

I repeat:
You MUST check the radial load limits on the engine, the motor, and the compressor.
You may end up with three jackshafts.
BTDT.

Mike Halloran
Pembroke Pines, FL, USA

 

[sbi]

Whose diesel? Most of the industrial's will handle 27 to 34 HP to the side, your 6.6 Pd is = to a 7" OD, JUST FOR SIMPLICTY 'S SAKE. A 7” B grove will pull 11hp with a tight belt, We always push the 5V since it will pull 16HP hand tight. Which reduces the side load on the engine.

SBI
Central Ne.,USA