Voltage Reduction Device (Vrd); Vrd Specification; Vrd Maintenance - Thermal Arc ARCMASTER 300 MST Operating Manual

10.0 VOLTAGE REDUCTION DEVICE (VRD)

10.01 VRD Specification

Description
VRD Open Circuit Voltage
VRD Resistance
VRD Turn OFF Time

10.02 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.
b) For fixed equipment, at least once every 12 months.
The owners of the equipment shall keep a suitable record of the periodic tests.
A transportable power source is any equipment that is not permanently connected and fixed in
the position in which it is operated.
In addition to the above tests and specifically in relation to the VRD fitted to this machine, the following
periodic tests should also be conducted by an accredited Thermal Arc service agent.
VRD Open Circuit Voltage
VRD Turn ON Resistance
VRD Turn OFF Time
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.
ARC MASTER
300 MST
15.3 to 19.8V
148 to 193 ohms
0.2 to 0.3 seconds The time taken to turn OFF the welding power
Description
Notes
Open circuit voltage between welding terminals.
The required resistance between welding
terminals to turn ON the welding power.
once the welding current has stopped.
Note 9
IEC 60974-1 Requirements
Less than 20V; at Vin=230V or 460V
Less than 200 ohms
Less than 0.3 seconds
46