Transducer ? Need analog signal for 250hp motor. Help

Hi I'm working on a project for a client who needs to automate the feed from a conveyor into a densifier powered by a 250hp 480v motor. I've already installed a AB powerflex drive to the conveyor motor. Now all I need is a 0-10 or 4-20 analog signal to vary the rate of material dumping into the desifier.

The reason I need to monitor the load on the 250hp motor is that the material being dumped changes from day to day and some of the material puts a huge load on to the motor. The clients current setup relies upon an operator visually watching a l.e.d. amp readout (via a c.t. donut) and pressing a stop button on the conveyor until the amps lower to a safe level to press the start button on the conveyor to resume.

Obviously the current setup has its problems as I'm sure most of you can already imagine.
If fact, a 250hp motor was recently burnt up due to an operator "paying close attention and reacting quickly".

After that expense, the client decided on an automated processing solution and enter - yours truly.

So I want to find a product that can meter the amperage and output an analog signal that I can control the feed conveyor. Sounds simple...

I haven't found what I'm looking for . Can anyone recommend a device that can read the 250hp amps (over 300 amps under a load at times) and generate an analog signal , either 0-10, 4-20, or engineering units that I can have a plc scale?
Thanks for any suggestions.
Bennie

You just need a suitable CT and current transmitter. I always go for 4-20ma rather than 0-10v as 0-10v is far more prone to injection of noise and induced voltages.

The power flex drive can be setup to control this.
Most drives have analogue inputs And analogue outputs
The drive can be configured in many ways.
Current limitation is s drive function.
250 hp. Or 0.25 hp the control is the same
It's the igtbs. That do the work.
Look up the conveyor or maybe torque options in the manual

Powerflex drives do have configurable analog outputs as mentioned. I don't generally recommend CT's on a PWM signal.
However, every time I read a current post about analog (and particularly referencing an AB or Siemens installation) I can't figure out why people are missing out on using ethernet for control and feedback. It's cheaper to install, easier to maintain, and offers much more flexibility. I can't imagine someone shelling out the $$$ for a 250 hp PowerFlex and then running analog circuits...

You are right my friend. I have just been configuring 4 x Siemens G120's using Ethernet/IP to AB
Really great tech these days
Just might be very expensive if you don't have a Siemens or AB PLC that can talk.
The S7-1200 is the cheaper option using profinet.
At the moment.
Basic control system might be easier

I would get current from drive. If the original motor burnt up, did they not have overloads for the motor? The drive should protect the motor from overload.

Seems to be some confusion. There is no drive on the 250hp motor.
The drive is on a 1 hp conveyor motor.
I want the load of the 250hp densifier motor determine the speed of the feed conveyor.

OHHHHH! Then just use a current transducer on the densifier leads, sum and average and use that as a speed reference to the conveyor.

https://www.automationdirect.com/ad...ansducers/AC_Current_Transducers/ACT750-42L-F

Three of those and an analog CLICK will get you out cheap.

Ah yes we were all confused. In that case use a 4-20 MA output current transducer.
https://www.automationdirect.com/ad..._Transducers/AC_Current_Transducers_(True_RMS)

Yes, use a current transducer as pointed to above, on the densifier current, then either setup a PID loop in the drive with a current setpoint, or at least invert the signal as a speed reference, and tune it with gain and offset.

Easy enough to do, we do it on stone saws, crushers, shredders, grinders, and other feeders...

That's it! That transducer and an analog CLIK is perfect! I need some I/O for stack lights , a horn , and some other input outputs I was wanting to add to the new setup.
Perfect and yes reasonably priced.
Thanks guys!

And you have a big advantage as you can control the speed of the conveyor you can speed it up, until you are at max of the densifier.
So a big advanrtage in efficiency and speed.

Which PowerFlex drive do you have on the conveyor? It might already have the internal logic capability to accomplish all of this without the PLC, it's a pretty simple process here.

one word of caution
with all loop control systems when you startup with nothing in the system the loop controller will go to max feed rate and flood the system until it sees a load feedback that it is looking for.
you need to control the federate at startup to prevent the overload at startup and brig the load up slowly

How are you starting the 250HP motor now? If you are using a soft starter (as you probably should) you may be able to get the amperage from it. I have a 125HP wood hog fed from a vibrator, the 125HP motor is started using a SMC Flex soft starter and controlled with Ethernet. I use a current averaging routine to shut off the vibrator when the load gets too high. You could create a routine that adjusts the PF drive speed based on the soft starter feedback.