Some acceleration tests on large synchronous pump motors

Acceleration tests on motors may yield very interesting and valuable information. These tests show the behavior of the motor in that region between zero speed and full speed through which each motor must pass every time it is started. The usual tests do not cover this range. In fact, it is difficult or impossible to obtain the actual motor characteristics in this range on many motors by any other means. The accelerating characteristics of a motor determine the margin by which that motor is able to start and bring its load up to speed in a reasonable length of time under the least favorable conditions which might be encountered. Acceleration tests may also be used in checking theories of operation, correctness of design constants, the presence of any peculiarities in the performance curves, and, in the case of induction and synchronous machines, any tendency to lock in at a subsynchronous speed. Where the motor has been installed and connected to the load, the characteristics of the load will affect the curves obtained. Tests made under these conditions may be of special value, since they represent operating practice.