Generator Belt Shrinkage and Burn

[aliccan]

Hi All ; I have designed generator driven belt and pulley system and used mercedes bus belt tensioner to tension 8 PK 1150 belt at 21 kW load.

The tension is around normal levels as i measured by gates tension meter.
The system has a flywheel shaft with 200 pulley on it and it is driving a 100 mm diameter pulley.

The 100 mm pulley is in the middle of the transfer shaft this shaft is heaving a 15 kW shock load every time the Air condition compressor clutch activates. (6 kW of the load is continous from the alternator)

This power is enough power to stall the engine but engine wins the stall and regenerates the normal 1500 rpm.
In one of the systems today we noticed that one of the Dayco belt was shrinked from 1150 to 1120 mm.
The engine room temperature is 90 Degrees Celcius
We are using cast iron pulleys
The engine room side is well ventilated
There were many signs of burn on the back side of the belt.
Is this normal or do i have system design failure.
You may find several pictures of the system as attached.

 

[wayne440]

I claim no expertise in mechanical design, but properly designed drives generally do not result in burned belts. Off hand, I believe that belt is about 1.2 inches (28mm) wide, my guess is that it is far undersized for your load.

 

[DRWeig]

Aliccan, welcome to eng-tips! As a new member, please read the forum policies, there is a link below. Posting the same question in more than one forum is strongly discouraged, as it leads to multiple threads going in multiple directions. In other words, confusion.


All, here is the link to aliccan's second post in Mechanical Engineering Other Topics:

http://eng-tips.com/viewthread.cfm?qid=327899

Good on ya,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[MiketheEngineer]

The belt burned - it is slipping.... bigger belt - more tension...

Figure it out

 

[HowDidYouBreakThat]

Your pulleys are too small. 100mm is not nearly big enough for a 15kw (19.5 Hp) shock load.

 

[aliccan]

I wonder if there is any calculation for the shock loads while selecting the pulleys ? This system is mounted on a vehicle with many many space restrictions. the maximum pulley diameter we could use was 4 inch (100 mm) one. Are there any document that i can use regarding the shock loads or is it your experience.

Thanks for your answers.

 

[HowDidYouBreakThat]

How much wrap do you have around the pulleys? The tensioner should be mounted as close as possible to the AC pulley to maximize wrap. Is it possible for you to post a picture of the setup?

Terry