Interpretation of recording

[flexoprinting]

Our drive system has blown 1 controller unit, 1 drive and several fuses, we think the issue is corrected so I am monitoring behavior to be sure.

I used a Techtronix 10Mv/Amp clamp with Fluke 8845A for these readings and would appreciate your thoughts/interpretation of them. The current and frequency signals are on a large rotating cutoff knife for paper sheeter unit. The top graph is ~ 2 1/2 hours run time with 5 occurances of stops after machine reaches full speed, Three of the stops show no current spike. The other two are showing a spike of + 13A, Motor FLA is 23.5A so I interpret this to not be a problem, however without expertise in this field I have doubts. The bottom graph is first occurrence magnified for clarity.

My questions are: Do you think this is normal Regenerative braking behavior or should I be concerned about these readings?
Should I perform a test with a o-scope and clamp instead to determine if the issue is resolved if so what should I look for?

Link

Chuck

 

[itsmoked]

It might be useful for us to know why, "we think the issue is corrected".

Keith Cress
kcress -

http://www.flaminsystems.com

 

[flexoprinting]

Hi Keith

This report is from local contractor we hired.

"A trip was recorded on October 30th 2016 Voltage up to trip point was found to be stable. With a
current spike of 300A noted on Input side of Drive. Dc bus voltage was found to be stable up to
trip point with a noted 100A dc current on dc bus at time of trip. Normal operating current from
start point 10/14 to trip at 10/30 Input drive voltage AB-406 BC405.8 CA 407.1 input median
current 60Amps. Dc bus current median was 65Amps and median voltage or 560VDC was
recorded. It was recommended that brake and tension adjustments be checked along with a
complete motor test of main motor. Which included testing of motor winding resistance and PI
testing of all motors within Cut star all motor tested passed with a PI of over 1.0. During break
check it was noted that it was out of adjustment."

We have since adjusted Paper roll brake per factory specs but have removed the $1200.00 a month recording equipment, trips have been minimized but still exist. The protection to shut system down so far has kept the issue from becoming dramatic. Hence the reason I would like to locate the Gremlin with individual motor readings.
The two largest motors are Knife and pull roll, I get similar readings on both within FLA of motors, the two smaller motors are pulling 2A each.

Chuck