Tweco 300 S Arcmaster - Manual (Page 43)

ARCMASTER ® 300 S
March 31, 2006 11-1
SECTION 11:
VOLTAGE REDUCTION DEVICE (VRD)
11.01 VRD Specifi cation
Description ArcMaster 400 S Notes
VRD Open Circuit Voltage 15.3 to 19.8V Open circuit voltage between welding terminals
VRD Resistance 148 to 193 ohms
The required resistance between welding
terminals to turn ON the welding power
VRD Turn OFF Time 0.2 to 0.3 seconds
The time taken to turn OFF the welding power
once the welding current has stopped
11.02 VRD Maintenance
Routine inspection and testing (power source)
An inspection of the power source, an insulation resistance
test and an earth resistance test shall be carried out.
a) For transportable equipment, at least once every 3
months; and
b) For fi xed equipment, at least once every 12 months.
The owners of the equipment shall keep a suitable record of
the periodic tests.
NOTE
A transportable power source is any equipment
that is not permanently connected and fi xed in
the position in which it is operated.
In addition to the above tests and specifi cally in relation to
the VRD fi tted to this machine, the following periodic tests
should also be conducted by an accredited Thermal Arc
service agent.
Description IEC 60974-1 Requirements
VRD Open Circuit Voltage Less than 20V; at Vin=208-230V or 460V
VRD Turn ON Resistance Less than 200 ohms
VRD Turn OFF Time Less than 0.3 seconds
If this equipment is used in a hazardous location or environments with a high risk of electrocution then the above tests should
be carried out prior to entering this location.