22
(14)
TP 1500 VRD, TP 1500 TIG VRD
General remarks VRD is an extra safety feature. VRD = voltage reduction device. Wherever possible, VRD
prevents output voltages which could be a hazard to life and limb.
Safety principle
of the TP 1500
VRD and TP 1500
TIG VRD
Welding-circuit resistance is larger than
the minimum human-body resistance
(greater than or equal to 200 ohms):
- VRD is active
- Open-circuit voltage is limited to 12 V
- Example: Accidentally touching both
welding sockets at the same time
(does not lead to any hazard)
Fig.15 VRD is active
Fig.16 VRD is not active
Welding-circuit resistance is smaller than
the minimum human-body resistance
(smaller than 200 ohms):
- VRD is inactive
- No limitation of the output voltage, so
as to ensure sufficient welding power
- Example: Start of welding
Important! Within 0.3 seconds of the end of welding:
- VRD is active again
- The output voltage is once again limited to 12 V
Warning indica-
tors when the
voltage limitation
is no longer
active
Warning! Welding voltage can be fatally dangerous. Depending upon which
process has been selected, LEDs (14) may flash. Flashing LEDs symbolise:
VRD is inactive. In this case, there is no limitation of the output voltage.
Fig.17 Flashing LEDs warn the user that: VRD is not active
To Next Page
Loading...
