OkiePC
Lifetime Supporting Member
I have a 5HP AC drive and motor that was installed in place of a 3 HP DC drive system about a year ago as part of a complete controls upgrade. It is an A/B 160 series drive (V/Hz) with 2 parallel dynamic brakes. It occasionally (1 to 10 times per day) faults on high bus voltage. The DBs are only rated to handle 5% duty cycle together. They get warm, but not blistering hot. Also, the perforamce of this part of the machine isn't where I'd like it to be.
In my application the drive is in decel about 25-35% of the time. It controls a cutter carriage that travels about fourteen feet back and forth. It makes a complete cut and return cycle 12 times per minute. It doesn't change directions as quickly as the old DC drive did. Luckily, the rest of the machine performs so much better that the bean counters are still very happy with the project overall.
We're getting ready to perform the same upgrade on another machine, but before we proceed, I'd like to cure this nuiscance problem. We are looking at a 7.5 HP Powerflex40 drive with sensorless vector. The PF40 has a built in IGBT for dynamic braking, but the standard a/b brake, again, is only rated for 5% duty cycle. The 160 drive also has a built in transistor for braking. I will contact our drive tech support to find out if I can choose a third party brake to get the duty cycle closer to what we need.
1. Will sensorless vector improve the drive's ability to decel and change directions
2. Will a vector drive need less dynamic braking duty cycle?
2. Is it true that a larger horsepower drive will allow better decel due to it's larger bus capacity or does it's current limit make that extra HP useless?
Thanks
Paul C.
In my application the drive is in decel about 25-35% of the time. It controls a cutter carriage that travels about fourteen feet back and forth. It makes a complete cut and return cycle 12 times per minute. It doesn't change directions as quickly as the old DC drive did. Luckily, the rest of the machine performs so much better that the bean counters are still very happy with the project overall.
We're getting ready to perform the same upgrade on another machine, but before we proceed, I'd like to cure this nuiscance problem. We are looking at a 7.5 HP Powerflex40 drive with sensorless vector. The PF40 has a built in IGBT for dynamic braking, but the standard a/b brake, again, is only rated for 5% duty cycle. The 160 drive also has a built in transistor for braking. I will contact our drive tech support to find out if I can choose a third party brake to get the duty cycle closer to what we need.
1. Will sensorless vector improve the drive's ability to decel and change directions
2. Will a vector drive need less dynamic braking duty cycle?
2. Is it true that a larger horsepower drive will allow better decel due to it's larger bus capacity or does it's current limit make that extra HP useless?
Thanks
Paul C.
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