Motor overspeed fault

Dear experts,

I'm building an industrial elevator which needs to transport cardboxes. The vertical movement is driven by a Sinamics G120C. I got it working but I have 1 problem. The motor I'm using can go up to 1400 rpm. When I move the elevator in an upgoing way I don't encounter any problems at all. I can set the setpoint up to 1400 rpm. But when I want to lower the installation I only can set my setpoint up to 400 rpm. When I set it to a higher speed, the elevator is "out of control". It's like after 1 second of running it gets into a free fall. This activates an error "Motor Overspeed".

I'm not quite good at drives and I hoped that maybe one of you people could help me understand this. Are there parameters that I need to adjust? I got the feeling that this is a torque problem.

Also, do you know what the best U/F characteristic is for this installation??

Thanks for your attention.

Greetings!

Hi,

Have a look at SINAMICS G120: Dimensioning and commissioning of serial hoisting equipment manual at page 12.

A handy reading for your application anyways!