🔍 Key Concepts

• Turning gear purpose – slow, controlled rotation of main shaft for maintenance, warming through, and preventing shaft deflection • Gear trains and speed ratios – how total reduction ratio changes when you drive a high‑speed pinion versus a low‑speed element • Location and function of high‑pressure (HP) pinion vs. low‑pressure (LP) pinion in a reduction gear set

💭 Think About

• Ask yourself: when you need very low turning speed and high torque at the bull gear, do you want to connect your small turning motor to a fast‑turning gear or a slow‑turning gear to get the biggest overall reduction? • Consider which choice mainly talks about mechanical advantage/gear ratio, and which ones are more about convenience (lubrication, coupling type, tooth shape). Which of those is the real design driver for a turning gear? • Think about where the "free end" of the HP pinion is in the train, and how driving there will affect the speed and torque at the main shaft compared to driving the LP pinion or the shaft directly.

✅ Before You Answer

• Verify which component in the reduction gear set has the highest rotational speed and lowest torque (that’s where a small motor can benefit most from extra ratio). • Check which option clearly addresses maximum overall gear reduction between the turning gear motor and the bull gear. • Mentally trace power flow: turning motor → engagement pinion → high‑speed pinion → main reduction gear (bull gear) → shaft, and note how many stages of reduction that path gives you.