🔍 Key Concepts

• Fail-safe design of electro-hydraulic crane brakes • Relationship between spring-set vs. hydraulically-set brakes and what happens on loss of pressure/power • What happens to a suspended load when the hoist pump is at zero stroke or there is loss of servo power hydraulic pressure

💭 Think About

• If hydraulic pressure is suddenly lost while a load is suspended, what design of brake (spring-set or hydraulic-set) would best prevent the load from accidentally dropping? • When the hoist pump is brought to zero stroke, is the crane intended to move or to hold the load in place, and what must the brake do in that condition? • In a safe crane design, does the brake tend to set or release when there is a loss of servo power hydraulic pressure?

✅ Before You Answer

• Identify which option describes a fail-safe condition (brake applies when pressure is lost). • Check which choices correctly pair spring-set with hydraulically-released, versus hydraulically-set with spring-released. • Confirm that in the correct description, the brake engages (sets) when either the hoist pump is at zero stroke or there is a loss of servo power hydraulic pressure, to safely hold the load.