Thermal Arc Viking 210GM, Operating Manual

Page: 32 / 42

Viking 210GM, 250GM
27
11.1 Improved Current Accuracy Calibration Procedure for the Digital Meter
WARNING 7
This calibration procedure should be carried out by a qualified electrical tradesperson.
The following procedure will give a current measurement accuracy of better than the factory
standard of approximately 5%.
a)
Equipment Required:
Viking 210 Viking 250
DC Ammeter
(certified up to
±
1% accuracy)
250A 300A
LOAD RESISTANCE of 0.1
Ω
5kW 8kW
Output Connecting Leads
b) Procedure:
i)
With the Viking switched off, connect the LOAD RESISTANCE and DC
AMMETER to the output terminals.
ii) Open the wirefeeder compartment door or remove the lefthand side cover (when
viewing the Viking from the front).
iii) Select maximum voltage switch positions: Coarse 18-20V Fine 4 (Viking
210GM)
Coarse 18-21V Fine 4 (Viking
250GM)
iv) Switch the Mains supply voltage to the Viking ON.
v) Ensure the DIGITAL METER is selected to read current.
vi) Short circuit the TORCH TRIGGER terminals to energise output welding terminals.
CAUTION 7
Do not allow the Viking to remain ON under load for more than ONE minute!
vii) Determine the output current as given by the DC AMMETER.
viii) Adjust SHUNT CAL. potentiometer on DIGITAL METER to read identically with
DC AMMETER.
ix) Open circuit the TORCH TRIGGER terminals to deactivate output welding
terminals.
x) Select minimum voltage switch positions: Coarse 18-20V Fine 1(Viking 210GM)
Course 18-21V Fine 1(Viking 250GM)
xi) Short circuit the TORCH TRIGGER terminals to energise output welding terminals.
Refer to
CAUTION 7.
xii) Determine output current as given by the DC AMMETER.
xiii) Confirm the minimum DIGITAL METER reading is within
±
2% of DC
AMMETER.
xiv) If the above is not met, offset the SHUNT CAL. potentiometer such that both the
minimum and maximum values are within
±
2%.
xv) The improved accuracy for DIGITAL METER is now complete.
xvi) Where fitted, position the meter cover over the hexagonal brass spacers taking care
not to trap loom wiring.