Specifications

MedWeld 3000 Catalog Revision 8
July 2002 Page 56 of 72
3-Level Detection System
A more advanced safety design is available with the MedWeld 3005. This design
incorporates the monitoring of the ground integrity, imbalance of current and also
monitors the resistance of the insulation covering the primary cables to verify that it
is greater than 250 K ohms to 2 M ohms. The verification of adequate primary
insulation is accomplished with the use an independent monitoring system. This
verification takes place during idle time where an isolation contactor removes the
manual transformer-gun from the power lines. If the insulation resistance is too low,
the control will generate a fault and prevent the isolation contactor from pulling in.
This design uses the advanced programming capability of the Allen-Bradley
TM
5/03
processor to build in a redundancy that assures full protection. On power-up and
each time the welding control remains idle for more than 30 minutes, the system will
automatically execute a verification test to ensure that the monitoring circuits are
functioning. If the safety monitoring system does not detect the simulated faults, the
Medar processor will generate a fault and prevent an unsafe condition from taking
place.
A standard shunt trip for the circuit breaker is used since the power to trip the
breaker is also the power to pull in the isolation contactor.
3-level Manual Gun Safety Protection System Installed
Minimal Requirements:
Circuit breaker with shunt trip
Isolation contactor
AB 5/03 – 8K processor (1747-L531)
AB output card for shunt trip – OA or OB type