In jaw crushers, how does choke crushing (operating with a full chamber) compare to free crushing in terms of capacity and power consumption?

Introduction / Context:
Crusher performance depends on feed conditions. “Choke” operation keeps the crushing chamber full, altering inter-particle breakage and throughput relative to lightly loaded (free) conditions.

Given Data / Assumptions:

• Same machine and feed characteristics, but different chamber loading.
• Choke implies continuous, full-feed operation.

Concept / Approach:
Choke crushing enhances inter-particle breakage and increases the product density and throughput (capacity). However, the higher load also raises power draw due to increased work on the material and frictional effects.

Step-by-Step Solution:
Compare capacity under free vs choke: choke is higher.Compare power: choke draws more due to greater material load.Therefore, (a) and (c) are both true.

Verification / Alternative check:
Plant data and vendor curves show improved tph in choke operation along with higher absorbed kW.

Why Other Options Are Wrong:
Less power: contrary to increased load.Single statements omit the coupling of both capacity and power changes.

Common Pitfalls:
Running starved-feed due to fear of power spikes; this often reduces efficiency.

Final Answer:
Both (a) and (c)