rsdoran
Lifetime Supporting Member
I know this isnt a plc question but so many of you are familiar with this drive and/or systems like it and these kind of problems I had to ask here.
Ok the this drive is on a feeder that feeds flat metal into a stamping press, we are on drive 5. BTW it is an Indramat DCK 21.3 servo drive.
The company that built the press and feeder came in and installed a new drive, line reactor, capacitor module, motor and new cables. The new drive was not configured so they used the old programming module and DI card at first but we kept having faults. They determined from the previous problems that the 24vdc had noise and that was causing the failures, faults and loss of communication. The put a pull down resistor across the 24vdc power supply but still had faults. HERE is the part I think is wierd...as I said originally they DID NOT use the NEW programming module (actually its more of a fault indicator/memory module) and the DI (digital input card). They did put in the new Programming module but still had faults.
THe OEM tech decided that the dry contacts from the relays needed MOV's so drove downtown and got some. While he was gone we isolated some of the 120vac items that go thru the relay contacts and still had a fault. While he was gone the Indramat tech changed the DI module and entered the variables then the OEM tech returned and put the MOV's in...ACROSS THE Normally open contacts of the relays that passed the 120vac to the ESTOP, air solenoid and oiler solenoid...NOTE: Across the normally open contacts...NOT the relay coil.
The company has a Fluke 97 50MHZ scopemeter. I used but didnt see any noise etc at first but I was looking more for harmonics. We had another fault Friday morning so we investigated REAL HARD. The 24vdc power going to the drive is clean with very little ripple, maybe 50 mv and no noticeable harmonics. The output power from the drive has an AC signal of 6 volts with a timebase of 50ns....ie 20MHZ if my math is correct. We isolated every device we could that gets power from the drive or the 24vdc supply but the signal stays there. We removed the 480vac incoming power to the drive and enabled the drive and this signal is gone.
The drive has a carrier wave of 4khz, standard. WHY/HOW could I be getting a signal, 6vac@50ns, like this from the drives power output that is just suppose to be an internal jumper from the incoming supply?
The old drives that failed were sent to Indramat and the reports for the first 2 were basically that the programming module had to be reloaded with the firmware. We know the last one physically burned a DI card. All these are symptoms of overvoltage/spikes/surges on the 24vdc. The faults were unique because there was a combo of E1 E3, watchdog timer pertaining to high voltage discharge etc. At first the Indramat people said it couldnt have an E1 E3 fault.
Got any ideas what I am seeing...is it something that I need to ignore or fear?
All thoughts are welcome.
Ok the this drive is on a feeder that feeds flat metal into a stamping press, we are on drive 5. BTW it is an Indramat DCK 21.3 servo drive.
The company that built the press and feeder came in and installed a new drive, line reactor, capacitor module, motor and new cables. The new drive was not configured so they used the old programming module and DI card at first but we kept having faults. They determined from the previous problems that the 24vdc had noise and that was causing the failures, faults and loss of communication. The put a pull down resistor across the 24vdc power supply but still had faults. HERE is the part I think is wierd...as I said originally they DID NOT use the NEW programming module (actually its more of a fault indicator/memory module) and the DI (digital input card). They did put in the new Programming module but still had faults.
THe OEM tech decided that the dry contacts from the relays needed MOV's so drove downtown and got some. While he was gone we isolated some of the 120vac items that go thru the relay contacts and still had a fault. While he was gone the Indramat tech changed the DI module and entered the variables then the OEM tech returned and put the MOV's in...ACROSS THE Normally open contacts of the relays that passed the 120vac to the ESTOP, air solenoid and oiler solenoid...NOTE: Across the normally open contacts...NOT the relay coil.
The company has a Fluke 97 50MHZ scopemeter. I used but didnt see any noise etc at first but I was looking more for harmonics. We had another fault Friday morning so we investigated REAL HARD. The 24vdc power going to the drive is clean with very little ripple, maybe 50 mv and no noticeable harmonics. The output power from the drive has an AC signal of 6 volts with a timebase of 50ns....ie 20MHZ if my math is correct. We isolated every device we could that gets power from the drive or the 24vdc supply but the signal stays there. We removed the 480vac incoming power to the drive and enabled the drive and this signal is gone.
The drive has a carrier wave of 4khz, standard. WHY/HOW could I be getting a signal, 6vac@50ns, like this from the drives power output that is just suppose to be an internal jumper from the incoming supply?
The old drives that failed were sent to Indramat and the reports for the first 2 were basically that the programming module had to be reloaded with the firmware. We know the last one physically burned a DI card. All these are symptoms of overvoltage/spikes/surges on the 24vdc. The faults were unique because there was a combo of E1 E3, watchdog timer pertaining to high voltage discharge etc. At first the Indramat people said it couldnt have an E1 E3 fault.
Got any ideas what I am seeing...is it something that I need to ignore or fear?
All thoughts are welcome.