Thermal Arc ARCMASTER 200 TS, Service Manual

Page: 39 / 96

9
VOLTAGE REDUCTION DEVICE (VRD)
9 – 1
VOLTAGE REDUCTION DEVICE (VRD)
1
VRD Specification
Table 9-1: VRD Specification
2
VRD Maintenance
Routine inspection and testing (power source):
An inspection of the power source should be car-
ried out.
a. For transportable equipment, at least once
every 3 months; and
b. For fixed 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 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 fol-
lowing periodic tests should also be conducted by
an accredited Thermal Arc service agent.
Table 9-2: Periodic Tests
If this equipment is used in a location or an envi-
ronment with a high risk of electrocution then the
above tests should be carried out prior to entering
this location.
The test of VRD is shown below:
1) In STICK welding mode, mark and then turn
potentiometer VR1 on PCB4 (WK-5449) all the
way to the left and turn on the electric shock
protector function (Voltage-Reduction-Device,
VRD).
2) Contactor function is put into the state of on
pushing Function button. Refer to section 6.
3) Verify the no-load voltage (OCV) using a DC
voltmeter. (The capability of the voltmeter
should be more than 100VDC.)
4) The normal no-load voltage is approximately
18V.
5) In STICK welding mode, mark and then turn
potentiometer VR1 on PCB4 (WK-5449) all the
way to the right and turn off the VRD.
6) Contactor function is put into the state of on
pushing Function button. Refer to section 6.
WARNING
Electric shock hazard. The unit will generate OCV
(Open Circuit Voltage) immediately when contactor
function is put into the state of on pushing Function
button at STICK mode.
7) Verify the no-load voltage (OCV) using a DC
voltmeter. (The capability of the voltmeter
should be more than 100VDC.)
8) The normal no-load voltage is approximately
65V.
Description
ARC MASTER
200TS
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.
Description IEC 60974-1 Requirements
VRD Open Circuit Voltage Less than 20V; at Vin=230V
VRD Turn ON Resistance
Less than 200 ohms
VRD Turn OFF Time Less than 0.3 seconds