powerflex 70 connections/parameters

[hounddog]

If it possible to connect two powerflex 70 inverters so that each inverter can be controlled independant if needed, then have a master pot to control box inverters at the same time.

for example, if you have to set the first powerflex 70 to run at 100 rpms, then set the second powerflex 70 to run at 80 rpms.

Then for some reason you want to adjust the speed of both of inverters at the same time with a master pot. So if you adjust the pot then both inverters would change the same amount.

Could someone possibly explain the best way to set this up?

thanks

 

[halosome]

powerflex 70 has 2 ch AI and 1 ch AO, and 3 DI (besides startstop). I am sure you can make a combination of those I/O on your application.

An example:
Master bot controls 1st pf70, and AO from 1st pf70s control 2nd Pf70.
since each pf70 got second AI ch, so you can still control them by another input.

 

[halosome]

and I would like to ask a shallow question here, if a fuse is added before the VFD, what is the normal rating you will choose? 2 times of the motor FLA?

 

[DickDV]

I would be tempted to do this kind of speed control with floating point or MOP.

Set up a 2 pole relay with its coil controlled by the "Master Increase Speed" button and another 2 pole relay with its coil controlled by the "Master Decrease Speed" button. Arrange the two poles of the Inc Spd relay to each feed the Inc Spd input of each drive. Do the same thing with the two poles of the Dec Spd relay.

Also, provide an "Individual Increase Speed" button and an "Individual Decrease Speed" button that feeds each of the two drives independently. These buttons would each be in parallel with one of the relay contacts
feeding that individual drive.

With this arrangement, using the individual buttons allows you to control each drive separately or preset speed offsets between the two drives. When the Master buttons are operated, the speeds will shift up or down for both drives simultaneously.