SSD/Parker 590 thyristor drive Missing Pulses
SSD/Parker 590 thyristor drive Missing Pulses
(OP)
I had a case yesterday where a Parker Hannifin (formerly Schackleton) drive has started tripping with message "Missing Pulse".
Managed to catch a trip. The recording below shows armature current (blue) and corresponding Iact. The Iact has a lot of ripple in it and it looks like it could be the +/-12 V supply that causes this. But there is no documentation and we all have a feeling that we could benefit from hardware schematics.

Questions:
1. Anyone had this with "mature" SSD drives? Tips?
2. Anyone has a copy of the drawings available? Links? Scans?
Managed to catch a trip. The recording below shows armature current (blue) and corresponding Iact. The Iact has a lot of ripple in it and it looks like it could be the +/-12 V supply that causes this. But there is no documentation and we all have a feeling that we could benefit from hardware schematics.

Questions:
1. Anyone had this with "mature" SSD drives? Tips?
2. Anyone has a copy of the drawings available? Links? Scans?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.





RE: SSD/Parker 590 thyristor drive Missing Pulses
RE: SSD/Parker 590 thyristor drive Missing Pulses
We do not want to risk the drive or motor and SSD doesn't seem to care. So a classical analogue repair seems to be the best we can do.
The next best thing is to adjust the Discontinuous parameter so supervision gets active somewhat higher up in current. That will, in its turn, probably necessitate a current controller P gain adjustment and, to guard against collector damages in the motor, add a 50/100 Hz detector that warns if there should be any REAL missing pulses.
Still interested in hardware diagrams.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: SSD/Parker 590 thyristor drive Missing Pulses
They do that from Ia, Ua, If and Uf.
In your drive Ia is measured by LEM or transformer current sensor? What is frequency for IAFBK in above picture?
What model drive is it?
Check this doc/page 5-6 http://manuali.eltex.biz/Manuali_Parker/590%20DRV%...
They provide more tips.
RE: SSD/Parker 590 thyristor drive Missing Pulses
A possible aside - if that current transducer is a LEM type then try adding an electrostatic shield around the conductor at the location where the LEM is positioned. I prefer to use adhesive copper foil with a drain wire soldered to the foil and connected to earth, but at a push I've used aluminium foil and a croc clip for a temporary arrangement. Watch the clearances to any live metal! The HF noise should drop away signifcantly and leave the true current waveform. The noise problem in the output is caused by dv/dt coupling from the conductor to the transducer as the conductor suddently shifts in potential relative to earth during commutation.
RE: SSD/Parker 590 thyristor drive Missing Pulses
If you look at the IAFBK signal just after the trip, it goes from noisy to quiet when armature current drops to zero. That is something that I ought to have noticed, myself.
Anyhow, the pump people decided to invest in a new drive. So everyone is happy!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: SSD/Parker 590 thyristor drive Missing Pulses