a question for PF753

Hi Guys

i am commissionning a PF753 via 20-COMM-E, there is "Stop Asserted" on HIM, but we still could start the drive(the running bit set) when the motor leads were disconnected. After we connected motor with drive, the 753 will trip when try to start.
my question is how come we still could start the drive when it is stop asserted?

thanks

It is not possible for the drive to actually be Running when the Stop Asserted is displayed. While I do not have strong direct experience with the PowerFlex 753, this is how every PowerFlex 7-series I have used works.

Where is the Stop command coming from ? If it is coming from the network, maybe your logic is rapidly setting it to False and back to True when the drive faults.

What is the fault code ? If it is cleared rapidly, check the Fault Log to determine what fault codes have happened recently.

Thanks Ken

we will receive the "Running" signal when all motor leads been disconnected,when we connect the leads back and tried to start the motor, it's been tripped out because of hardware overcurrent which based on the fault code.

thanks

I think you really have two questions:

1. Why can I start the drive when 'Stop Asserted' appears to be shown on the HIM module ?

2. Why does the drive trip on overcurrent when I try to start the motor ?

If this were my system, I would disconnect the motor leads and try to solve question 1.

Your exact description is impossible: the drive cannot start if a STOP signal is asserted. You need to figure out where the STOP signal is coming from, and determine how it is removed prior to the START signal being sent to the drive.

Once you understand how the Start and Stop signals are getting to the drive, you can continue to investigate why the drive stops on overcurrent.

If this is a new installation (you described it as 'commissioning'), it is very likely that the drive is not configured correctly (too low maximum current) or there is physically something jammed or shorted at the motor.

Ken

I am going to check the configuration tomorrow, one more question, if there is a stop signal from network(PLC) not from VFD digital input, does "Stop Asserted" message still appear on HIM?

thanks

Yes.

If the STOP bit in the I/O connection is true, the 'Stop Asserted' message will be displayed.

If a STOP command is asserted by any interface, the drive will not start. STOP commands cannot be masked out and always override START commands.

I believe Parameter 288 will show you which stop signal is creating the "stop asserted".

When you say that you get the "running" signal, where are you seeing this? Check out Parameter 210. Bit #2 is the running signal (that's the 3d bit from the right because it has bit 0 and bit 1 before it). I suspect you are looking at the wrong thing.