Variable-speed motor electric working condition subsynchronous load test method

The invention discloses a variable-speed motor electric working condition subsynchronous load test method, and relates to a working condition subsynchronous load test method, in particular to a variable-speed motor electric working condition subsynchronous load test method. The invention aims to solve the problem. The method comprises the specific steps that a squirrel cage asynchronous machine is coaxially connected with variable speed motors with different rotating speeds through a gearbox; the frequency conversion unit is started, the output knife switch is closed, the output frequency of the synchronous generator is adjusted to be the same as the output frequency of the squirrel-cage asynchronous machine, and the output electric switch is closed to realize grid connection of the frequency conversion unit and the squirrel-cage asynchronous machine; the frequency conversion unit reduces the rotating speed, and the squirrel-cage asynchronous machine becomes an asynchronous generator; the frequency conversion