Need advise on trouble shooting our Universal III Power serial # 25118. This is how it is behaving:
When set in CYCLE and RUN mode; the cylinder moves forward until the carriage cam releases the 4LS limit switch, then the carriage immediately reverses back to home position.
MANUAL mode; using the FORWARD lever the cylinder accelerates forward and brakes at the end of the press, then putting in REVERSE the cylinder returns and brakes to a stop. The limit switch cam has been maxed out and the braking rheostat nearly maxed to get the best performance, however, the acceleration and braking is weak compared to other presses I have seen.
HERE IS SOME BACKGROUND description of the work already done to the press:
– Inside the motor casing the PVC wiring from the motor junction box to the coils was falling apart and has been replaced. The windings of the motor look fine, with no signs of overheating.
– After this work was done, the motor was professionally tested and the drive armature, series field and shunt field check out as OK.
– The flexible wiring to the motor has been replaced (one of the eight wires was broken). All other wiring checks out OK to the motor using an ohms meter.
– Clutch has been adjusted to specification, and verified by marking the clutch plates. There is no slipping during acceleration or braking
– The relays are original but the contacts are very badly pitted. They have been cleaned up and each contact checked with ohms meter when manually pressed together. This probably does not duplicate the action of the relay contacts and we have not tested them live yet.
– The main rotary switch for setting in manual_cycle_run has been checked out and is working correctly according to schematics.
– Limits switched work and are in good condition
THIS IS WHAT HAS NOT been checked:
– Output voltage from the rectifiers (what can I expect with rheostat at at the minimum?)
– Not checked the output of each relay contact when in operation.
SO MOVING FORWARD, any suggestions before replacing the forward/reverse and control relays?
I am not familiar with the Schneider Electric relays as recommended by Basil Head so does anyone have advise how to wire them?
Thanks in advance
Thanks for the reply and interest
All wiring of the motor was marked very carefully during the minor rewire to the coils and double checked. In addition, this was also checked and verified when the motor was tested by Access Electrical Motors a rebuild specialist. When the motor was installed the wires were connected as per schematic and double checked and checked again.
When in MANUAL mode using the forward and reverse lever the carriage accelerates and brakes as expected, so it indicates the control circuits in CYCLE and RUN are not working correctly. I should measure the output of the relays when in operation but have not had the time.
At the third limit switch the carriage should slow. At the fourth it should reverse. Is it possible that some wires were mixed up when you reinstalled the motor?