Procedure No.
:FFPL/CWM/13
PROCEDURE FOR CALIBRATION Revision: 0
WELDING MACHINES Date : 07/11/2015
Page : 1 of 2
1.0 Scope
1.1.0 This procedure describes the method of Calibration of Welding Machines used during
fabrication of code items.
2.0 Responsibilities
2.1.0 Welding engineer is responsible for carrying out calibration of Arc Welding Machines used
during fabrication of CODE items.
2.2.0 A calibrated Digital clamp on AC/DC HI Tester shall be used for calibration of welding
machines. Digital clamp AC/DC HI Tester shall be calibrated on a master calibrator once in
12 month period. Instrument shall have a measuring range of alternating current (or)
direct current upto 1000 ampheres & 600 volts.
3.0 Procedure
3.1.0 Set the mode AC or DC & parameter voltage or amphere accordingly in the digital clamp
on AC/DC HI Tester.
3.2.0 Zero adjustment must be performed for measuring DC current before clamping on the line
to be measured.
3.3.0 After zero adjustments are made, clamp the line to be measured so that the arrow on the
side of the clamp sensor point is in the direction of current flow & the line is positioned in
the centre of the sensor jaws. (A negative reading will result if the arrow points in the
opposite direction)
3.4.0 For measuring AC current, clamp the tester on the conductor so that the conductor passes
through the centre of the clamp core.
ProcedureNo.: FFPL/CWM/13
PROCEDURE FOR CALIBRATION Revision: 0
WELDING MACHINE Date : 07/11/2015
Page : 2 of 2
3.5.0 For measuring AC voltages, the polarity of the leads can be ignored (+, -)
3.6.0 For measuring DC Voltage, connect the Red (+) lead to the +side of the circuit to be
measured & the Black (-) lead to the –side. A negative reading will result of the leads are
reversed.
3.7.0 After performing the initial settings as above, strike the Arc on Test/Work Piece, note the
readings of current in the clamp on AC/DC tester. Also note the readings of ammeter fixed
on the welding machine.
3.8.0 By increasing the current in different steps, note the current values in the clamp on AC/DC
tester & ammeter. Minimum of 4 different current settings shall be done.
3.9.0 The maximum permissible input for clamp on AC/DC HI tester is 1000 ampheres & 600
volts. Care to be taken not to exceed these limits during calibration.
3.10.0 The values of current in clamp on AC/DC HI Tester & ammeter in welding machine are
recorded on a welding machine calibration certificate.
3.11.0 The maximum accepted % variation shall be +/-8%
3.12.0 Re-calibration of welding machines shall be carried out for every 1 year interval.
4.0 Records
After satisfactory completion of calibration , HOQ shall approve the calibration of
welding machine & affix a sticker to it. Details of welding machine serial no., calibration
date, re-calibration date & signature of HOQ shall be recorded on the sticker.
Prepared By Approved By Reviewed By
Welding Engineer-QA/QC Head-QA/QC Authorised Inspector
Prepared By Approved By Reviewed & Accepted By
Engineer-QA/QC Head-QA/QC Authorised Inspector
