Advice on asynchronous machines

I have constructed a multi machine system, however an error crops up during operation, when the motors return to 0 speed they begin regenerating. Has anyone come across this before or have any suggestion as to where i may have gone wrong?

Apologies, by multi-machine i mean a model with a number of asynchronous machines in it. Only one computer involved. I am using a set of asynchronous motors to demonstrate a real life system. I have set the parameters according to their real life counter parts, there is no error message, the problem is in the behaviour of the model. I input a square wave speed reference and a static torque value, when the speed of the machine returns to 0 (it performs correctly up to the speed ref) the machine generates exactly as it does when the speed falls under generating torque.

[Jan]

What exactly is a "multi machine system"? A Simulink model or a pool of parallel working computers? Which motors? And what error messages appears?

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