When modeling multiple Synchronous Machines (similar in rating and characteristics) at a bus and inter-machine dynamics are not important, it is possible to model a number of machines as a single entity. Simulating multiple machines coherently will speed up the simulation and also avoid any unwanted interactions between them.
Input parameters are provided called Machine Scaling Factor for the purpose of specifying this number of coherent machines. If machine inter-dynamics are necessary for your study, simply connect the required amount of individual machines to the bus, and set Machine Scaling Factor? to No. This factor can also be used to scale the machine rating. Entering a 0 will disable the machine altogether.