Yaskawa Drive Question

I know this isn't really plc related but I can't find any other "controls" type forum that is as good as this one.

Anyway, our team has been designing and installing part of a wood manufacturing system that has a total of 5 Yaskawa Drives;

1- CIMR-F7U4015
2- CIMR-F7U47P5
2- CIMR-F7U4037

Typically each drive has a braking transistor and several braking resistors tied to it.

We have recently been looking into utilizing a "regen" unit and having all of the drives on one "Common DC Bus". I looked at Yaskawa's website and they specifically say "does not support common DC busing of multiple drives".

I was looking for some application help, and to see what other people have done in the past trying to accomplish this.

Thanks,

-Lance

We used Yaskawa drives in the past, and never again will I ever select them.

In the instances in which we had multiple Servo's, and required regen systems, we had to manufacture our own bridge resistor network, enclose them in a seperate JB, and pray that there was not too much heat.

The applications and hardware work well, but the Yaskawa support is little to be desired.

I'm guessing here but, since the drives already have an internal brake chopper, it is likely that the DC bus + and - terminals are not brought out to the power terminal strip. Instead, they give you the two resistor connections.

To gain access to the DC bus, you would have to open up the drives and modify the connections. There goes the warranty.

There are other considerations as well when common DC bussing. If the charging circuits for each drive are designed really thin (usual to reduce cost) then none of the individual drives will have the capacity to charge up all of the capacitors at once.

You might want to do a cost analysis to be sure saving the energy has a decent payback. Usually, you have to be braking hard around 40+% of the time to make it pay.