Brijm
Lifetime Supporting Member
A customer has two AB Powerflex 753 VFD running on two identical powdered metal presses. Both where installed about two years ago. One is running fine. The other has had a problem during decel where it gets a loss of phase fault (#17), and they have to power down the unit. They report that they have prevented this by speeding up the decel from 180s to 120s and using dynamic braking, although the brake resister is getting extremely hot.
They may need a larger brake resistor to handle the load, but their question and mine, is why on this press would the motor be causing a loss of phase fault on the one VFD (High DC Bus Ripple). We work on, and install a large number of VFD's in the area, and I have never encountered this.
Note (Brake Resistor normally are installed on larger PM presses. Not for stopping time, but to absorb the energy after compaction/ejection. Would load reactors help? I have been leaning toward a problem in the drive, but wanted to see if someone could explain this to me.
Also, we set the inPhase LossActn to either ignore or alarm, and still encounted a fault, that required the drive to be reset.
They may need a larger brake resistor to handle the load, but their question and mine, is why on this press would the motor be causing a loss of phase fault on the one VFD (High DC Bus Ripple). We work on, and install a large number of VFD's in the area, and I have never encountered this.
Note (Brake Resistor normally are installed on larger PM presses. Not for stopping time, but to absorb the energy after compaction/ejection. Would load reactors help? I have been leaning toward a problem in the drive, but wanted to see if someone could explain this to me.
Also, we set the inPhase LossActn to either ignore or alarm, and still encounted a fault, that required the drive to be reset.