LOAD DETERMINATION DEVICE FOR ELECTRIC CHAIN BLOCK AND LOAD DETERMINATION METHOD

摘要

Provided are a load weight determining apparatus and load weight determining method for an electric chain block that are capable of determining a load weight from a torque current of the electric chain block, with high accuracy and within a short period of time after starting a lifting operation. The load weight determining apparatus is for use in an electric chain block having a lifting-lowering motor 12 and an inverter controller 11. The lifting-lowering motor 12 rotates a sheave 15 to wind up and unwind a chain 16 engaging the sheave 15. The load weight determining apparatus has a current detecting element 21 detecting a motor current supplied to the lifting-lowering motor 12 from the inverter controller 11, and a load weight determining unit 20. A torque current is calculated from the motor current detected by the load weight determining unit 20, and a variation cycle of the torque current is calculated. An average torque current value over a period of time corresponding to the variation cycle is calculated, and the average torque current value is compared with a set threshold to perform load weight determination.