The propeller may be overloaded which caused by some reasons when ship has been serviced for a period of time . as a result , the rated revolution of the engine cannot be achieved , or the engine may be on overloaded operation condition . it will not be in the optimum matching between the propeller and the engine 船舶在使用过程中，常因各种因素使螺旋桨出现负荷过“重”的现象，主机达不到额定转速或超负荷运转，桨机不能处于最佳匹配；另外当船舶人为地降速航行时，主机处在半负荷情况下工作，如果转速下降太多，使得主机的工作条件变坏，容易引起主机部件的损坏。
The test shall demonstrate to the satisfaction of the owner that the equipment meets all specified performance criteria , is properly installed and anchored , and operates smoothly throughout the specified speed range without exceeding the full load amperage rating of the motor or excessive motor heating 测试应该让用户满意，证明这些设备符合所有规定的性能标准，经过正确的安装和锚固，在额定转速范围内运行平稳，没有超过电机的额定满负荷运转电流安培数，或发生电机过热。
