# Thread: Bull gear & Pinion gear Drive Problem

1. ## Bull gear & Pinion gear Drive Problem

Dear Seniors.

I have a Bull gear & Pinion gear related problem. This is a practical problem and I am no expert in design or calculations.

A bull gear moves a load of 450MT. This Bull gear is 6m in diameter and is supported on a large ball bearing.

The bull gear is driven by a single pinion with electric drive at single point.

In due course of time, the bull gear is requiring more torque and I am suspecting the problem is with single driving point of bull gear.

Because I have seen in large slewing crawler cranes the gears are driven by 5 nos of smaller pinion gears.

If we provide 3-4 multiple pinions all around the bull gear(may be in an equispaced way), will it reduce the torque.

If I ask in a straight way,

If all else is okay, is it suggested to drive a large bull gear of 6 m diameter with one single pinion.

Or is it better to distribute the load to 3-4 smaller driving pinions with load/torque sharing.

Which is a the better alternative and Why?

How the claim can be proven with design calculations.

With Best Regards,

Krishna Chaitanya.

2. If the system requires more torque now than in the past, something is changing. What's changing? The number of pinion gears did not change, so how will increasing the number of pinion gears solve the problem? Something else is changing. Something is creating more and more friction in your system. What are the possible sources of friction? Maybe the alignment of the pinion gear and the bull gear is not right, and one of the gears is wearing away. Do you see a collection of steel dust anywhere?

3. Something is broke... Friction comes from somewhere.