Altivar 312 Braking

[denise01 3]

Hello, I am driving a 4 KW Motor with a large fly wheel using a 4KW Altivar 312 415 volt. It is taking too long to come to a stand still. I have tried stopping the motor using Ramp and setting the Deceleration setting to 1 but still too slow. I have installed a Braking Resistor but not sure of the best Setting Mode to use for a more effective stopping time. Regards Peter

[rajsiyer 7]

Hi, You have to enable the dynamic braking parameter dBr in the DRC(Drive characteristics) menu. It has to be set in run. I am not sure whether the menu in Altivar 312 is the same as other Altivars I've seen, but dynamic braking has to be enabled. If dynamic braking has been enabled the decelration time parameter uses the dynamic-braking resistor to fulfil its need to divert the kinetic energy to the braking resistor as heat. There will be a few more parameters limiting the maximum current taken by the resistor. If you need to stop like hitting a wall, then you can try DC-Injection braking. Again here, you've a choice as to the DC-injected current-limit & maximum time of injection. Usually DC injection can be done when the speed has come below a certain low value, where it is safe to assume that mechanical impact will not shear the shaft! This is a real possibility at higher speed. There are many other tricks like using some DIs for braking functions. I am not sure if Altivar supports regenerative braking. Next to mechanical braking, this is the fastest stopping method. This is followed by plugging (Reversing torque), DC -injection & lastly Dyn.Braking. One has to be careful even while using dynamic braking as the kinetic energy of the flywheel can burn-up the resistor. Tell me how it goes. regards, Raj S. Iyer

[denise01 3]