Red Seal Mobile Crane Operator Practice Exam

What is the function of the crane's load moment indicator (LMI)?

1. To assess the fuel requirements of the crane

2. To monitor the load being lifted and prevent overload conditions

3. To calculate the operational efficiency of the crane

4. To provide GPS data for crane placement

The correct answer is: To monitor the load being lifted and prevent overload conditions

The load moment indicator (LMI) plays a crucial role in crane safety by monitoring the load being lifted and ensuring that it does not exceed the safe operating limits of the crane. The primary function of the LMI is to measure the load’s weight and the length of the boom to calculate the moment created by the load. This moment is then compared to the crane's rated capacity for that particular configuration. By providing real-time data about the load, the LMI helps prevent overload conditions, which can lead to crane failure or tipping. If the load approaches the maximum limit, the LMI can trigger alarms or limit the crane's movement, ensuring that the operator is alerted to the potential danger and can take action to reduce the load or adjust operations accordingly. This function is critical for maintaining safety and preventing accidents on the job site.