D Follow the guidelines in the Applications Manual for the Revised surfaces. NIOSH Lifting Equation (Publication No. 94−110) when manu- D Do not service unit near flammables. ally lifting heavy parts or equipment. XMT 450 CC/CV TM-257 220 Page 1...
2. Do not place your body between welding cables. Arrange cables If cleared by your doctor, then following the above procedures is recom- to one side and away from the operator. mended. TM-257 220 Page 2 XMT 450 CC/CV...
Safe10 2012−05 Keep flammables away from welding. Do not weld near flammables. Safe12 2012−05 Welding sparks can cause fires. Have a fire extinguisher nearby, and have a watchperson ready to use it. Safe14 2012−05 XMT 450 CC/CV TM-257 220 Page 3...
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Become trained and read the instructions before working on machine. Safe35 2012−05 Connect Green Or Green/Yellow grounding conductor to ground terminal first. Connect input conductors (L1, L2, L3) to line terminals. Safe36 2012−05 TM-257 220 Page 4 XMT 450 CC/CV...
Supply Current Negative Primary Voltage Panel Inductance Degree Of Protection Alternating Current (AC) Foot Control Lift-Arc Trigger Hold Operation (GTAW) Voltage Gas Metal Arc Maximum Effec- Welding (GMAW) tive Supply Cur- 1eff rent XMT 450 CC/CV TM-257 220 Page 5...
2,172,158 VA). It is the responsibility of the installer or user of the equipment to ensure, by consultation with the distribution network operator if necessary, that the system impedance complies with the impedance restrictions. ce-emc 1 2014-07 TM-257 220 Page 7 XMT 450 CC/CV...
Use cart or similar device to move unit. Line Disconnect Device Locate unit near correct input power supply. 18 in. (460 mm) Ref. ST-151 556 / 800 611 / Ref. 250 026-B Notes TM-257 220 Page 10 XMT 450 CC/CV...
**Weld cable size (AWG) is based on either a 4 volts or less drop or a current density of at least 300 circular mils per ampere. ( ) = mm for metric use ***For distances longer than those shown in this guide, call a factory applications rep. at 920-735-4505 (Miller) or 1-800-332-3281 (Hobart). Ref. S-0007-K 2013−10 TM-257 220 Page 11...
Current feedback; +1 volt DC per 100 amperes. AMPERAGE Voltage feedback; +1 volt DC per 10 arc volts. VOLTAGE Circuit common for 24 volt AC circuit. Chassis common. *The remaining sockets are not used. TM-257 220 Page 12 XMT 450 CC/CV...
The minimum post−flow time is 5 seconds. The maximum post− flow is 24 seconds (post flow set- tings are not adjustable by the end user). GAS OUT Ref. 252 021-A / 257 348-A TM-257 220 Page 14 XMT 450 CC/CV...
4 Conductor data in this section specifies conductor size (excluding flexible cord or cable) between the panelboard and the equipment per NEC Table 310.15(B)(16). If a flexible cord or cable is used, minimum conductor size may increase. See NEC Table 400.5(A) for flexible cord and cable requirements. Notes TM-257 220 Page 15 XMT 450 CC/CV...
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Welding Power Source Line Terminals ures to put unit in service. Input5 2013−04 Notes Work like a Pro! Pros weld and cut safely. Read the safety rules at the beginning of this manual. TM-257 220 Page 17 XMT 450 CC/CV...
(See Sections 6-2 thru 8-3). played for approximately three seconds Mode Switch after the arc is broken. Remote 14 Receptacle Weld Output Terminal (−) Adjust Control Left Display Right Display Power Switch 10 Weld Output Terminal (+) TM-257 220 Page 18 XMT 450 CC/CV...
Turn off power before making con- nections. Connect desired remote control to Remote Negative (−) Weld Output Terminal 14 receptacle if required. Foot Control TIG Torch Gas In Connection (Optional) Positive (+) Weld Output Terminal Gas Cylinder Workpiece TM-257 220 Page 20 XMT 450 CC/CV...
For best results, gently scratch the tungsten electrode to the work to initi- ate an arc. To minimize arc flare at the end of the weld, pull back the electrode quickly to extinguish the arc. TM-257 220 Page 21 XMT 450 CC/CV...
Touch tungsten electrode to at the end of the weld, pull back the Preset amperage is shown in the Right Dis- workpiece at weld start point. Slowly lift electrode quickly to extinguish the arc. TM-257 220 Page 22 XMT 450 CC/CV...
For best results, gently scratch the tungsten electrode to the work to initi- ate an arc. To minimize arc flare at the end of the weld, pull back the electrode quickly to extinguish the arc. TM-257 220 Page 23 XMT 450 CC/CV...
For self-shielding wires (FCAW), ad- For typical system connections refer to has a voltage control. This voltage con- Section 7-1. trol will override the Adjust Control of just Arc Control to FCAW setting. TM-257 220 Page 25 XMT 450 CC/CV...
Positive (+) Weld Output Terminal 10 Gas Cylinder cored wires are not pulsed. No pulse Negative (−) Weld Output Terminal Use of shielding gas is dependant on Wire program available for FCAW. Ground Cable to Workpiece Type. TM-257 220 Page 26 XMT 450 CC/CV...
Rotate Mode Switch to PULSED MIG posi- formation. Left Display tion as shown. Right Display When Pulsed MIG mode is selected, Adjust Control Left and Right Display will show PPP PPP. Arc Control is not functional. TM-257 220 Page 27 XMT 450 CC/CV...
Negative (−) Weld Output Terminal Gas Hose wires require DCEN (straight polar- Ground Cable to Workpiece 10 Gas Cylinder ity). Workpiece Use of shielding gas is dependant on Wire Voltage Sensing Clamp Type. TM-257 220 Page 28 XMT 450 CC/CV...
The Left Display toggling momentarily For self-shielding wires (FCAW), ad- For typical system setup connections refer pauses while the preset voltage is ad- to Section 7-5. justed. just Arc Control to FCAW setting. TM-257 220 Page 29 XMT 450 CC/CV...
For best results at the end of the weld, The preset amperage is shown in the Right pull back the electrode quickly to extin- Display with the Amps Indicator lit. guish the arc. TM-257 220 Page 31 XMT 450 CC/CV...
This helps eliminate electrode sticking dur- ing arc initiation. For best results at the end of the weld, pull back the electrode quickly to extin- guish the arc. TM-257 220 Page 32 XMT 450 CC/CV...
Secondary Fan Motor Fan Motor Ribbon Heat Sink Heat Sink Solenoid Cable Supplementary Protector Operator Interface Board Process Voltmeter Ammeter Selector Remote 14‐Pin Receptacle Voltage RC50 Weld Process Arc Control Amperage Control Adjust TM-257 220 Page 34 XMT 450 CC/CV...
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Current Stabilizer Transducer Negative (−) Positive (+) Weld Output Weld Output Terminal Terminal Work Electrode Weld Voltage Feedback Weld Voltage Feedback Weld Current Feedback Control Circuit Primary Circuit Weld Current Circuit ♦ Optional XMT 450 CC/CV TM-257 220 Page 35...
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PC1 Provides primary current feedback to invert- Provides weld output connection to the • Contains weld control process er control board PC1 from main transformer workpiece of the weld circuit. TM-257 220 Page 36 XMT 450 CC/CV...
Use MILLER Testing Booklet (Part No. 150 853) when servicing this unit. See the Miller Extranet for service memos that may aid in the repair of this product. Measure voltage of input capacitors according to Section 10-2 and be sure voltage is near zero before touching any parts.
Proceed with job inside unit. Rein- stall right side panel when finished. 400 VAC input: + lead to lower terminal, − lead to upper terminal Ref. 256 682-A TM-257 220 Page 38 XMT 450 CC/CV...
E (−) B (AC Line 2) E (−) C (AC Line 3) If the input rectifier diodes are defective, check the three poles of the input contactor W1, the DMM should read OL. XMT 450 CC/CV TM-257 220 Page 39...
PM1 and PM2 2. Check function of IBGT’s in PM1 and PM2 with IGBT tester (MILLER Part No. 043 553). Disconnect gate lead Plug 3 from receptacle RC3 on Inverter Control board PC1. Connect tester to module terminals and gate lead plug as follows: Module IGBT Tester Positive Lead −...
Re-install terminal screws after checking before continuing. 4. Check bus capacitors C3, C4, C5, and C6 for a short using the ohms position on the DMM. XMT 450 CC/CV TM-257 220 Page 41...
Disconnect lead at interconnect PC2 for proper measurement. Pre-power checks are now complete. Remove earth grounded wrist strap before performing any checks or procedures with power ap- plied to the machine. Ref. 255 761-A XMT 450 CC/CV TM-257 220 Page 43...
See Section 10-11 or 10-13 for test points and values and Section 13 for parts location. Use MILLER Testing Booklet (Part No. 150 853) when servicing this unit. See the MILLER Extranet for service memos that may aid in the repair of this product. Trouble Remedy No weld output;...
Thermistor resistance will have dropped to <130 ohms (shorted) or will have risen to >1.2M ohms (open). Wiring malfunction. Check condition of wiring. Front panel display board Replace PC3. PC3 malfunction. XMT 450 CC/CV TM-257 220 Page 45...
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−−−−−−− function. within allotted time. LED3 is lit on In- verter Control Board PC1. Tank capacitors C1 and C2 Check the indicated value of (too high of a value). C1 and C2. TM-257 220 Page 46 XMT 450 CC/CV...
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With unit on, wait 15 minutes limit. Output stops and cooling high of a welding current for for unit to cool. Reduce am- fan runs. too long. perage, voltage, wire feed speed, or duty cycle before welding. XMT 450 CC/CV TM-257 220 Page 47...
Always check unit before applying power (see Section 10-1). 10-11. Troubleshooting Circuit Diagram For Welding Power Source (All Models) (Use With Section 10-12) V4 V5 R11, V7 TM-257 220 Page 48 XMT 450 CC/CV...
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Always check unit before applying power (see Section 10-1). Test Equipment Needed: 256 909-A XMT 450 CC/CV TM-257 220 Page 49...
+14 VDC in Stick and Scratch Start TIG modes when low open circuit voltage mode is enabled. +24 volts DC when gas is flowing. (RC6-6 reference) TM-257 220 Page 50 XMT 450 CC/CV...
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Always check unit before applying power (see Section 10-1). Notes XMT 450 CC/CV TM-257 220 Page 51...
Be sure plugs are secure before test- ing. See Section 10-14 for values during testing. Inverter Control Board PC1 No testing required for remaining plugs and receptacles. Test Equipment Needed: 250 818-C / 255 763-A TM-257 220 Page 52 XMT 450 CC/CV...
Input capacitor feedback; +282 volts DC with respect to RC4-4 (top+) Not used Input Input capacitor feedback; +282 volts DC with respect to RC4-6 (bottom+) Input Input capacitor feedback; Reference for pin RC4-1 (top-) Not used XMT 450 CC/CV TM-257 220 Page 53...
Indicates input bus capacitor voltage imbalance HELP 6 (See Section Normal LED 3 10-10 ON−Red Indicates primary circuit control malfunction HELP 6 (See Section Normal LED 4 10-10 ON−Red Indicates primary current detect malfunction HELP 6 (See Section TM-257 220 Page 54 XMT 450 CC/CV...
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Always check unit before applying power (see Section 10-1). Notes XMT 450 CC/CV TM-257 220 Page 55...
Be sure plugs are secure before testing. See Section 10-17 for specific values during testing. Interconnect Board PC2 No testing required for remain- ing plugs and receptacles. Test Equipment Needed: 255 761-A / 233 080-D TM-257 220 Page 56 XMT 450 CC/CV...
Not used Line voltage with respect to pin RC9-10 Line voltage with respect to pin RC9-10 Line voltage with respect to pin RC9-6 or RC9-8 No testing required for remaining plugs and receptacles. XMT 450 CC/CV TM-257 220 Page 57...
Be sure plugs are secure before ap- plying power. See Section 10-19 for specific values during testing. Front Panel/Display Board No testing required for remain- ing plugs and receptacles. Test Equipment Needed: 243 575-B / 255 763-A TM-257 220 Page 58 XMT 450 CC/CV...
−24 volts DC, unregulated DC voltage with respect to GND, power feed to front panel pcb Input Negative weld output terminal; used for output voltage feedback Not Used Input Positive weld output terminal; used for output voltage feedback XMT 450 CC/CV TM-257 220 Page 59...
Weld Output Terminals Check open-circuit voltage be- tween terminals according to Sec- tion 10-11 (voltage V-15) If correct voltage is not present, repeat troubleshooting procedures. Reinstall cover and side panels if removed. 252 018-A TM-257 220 Page 60 XMT 450 CC/CV...
15 volts DC. Front Panel And Display Board PC3 Remove wrapper. Place switch position 1 in the Closed position by pressing actua- tor toward board. Reinstall wrapper. 256 682-A / 243 575-B XMT 450 CC/CV TM-257 220 Page 61...
Right Side Panel Interconnect Board PC2 Voltmeter Remove right side panel. Connect unit to a 400 VAC line. Connect a Miller Load Bank to the weld terminals, set load bank switches to off. Connect two DVM’s as shown. Select MIG process.
Blow Out Inside 11-2. Blowing Out Inside Of Unit Do not remove case when blowing out inside of unit. To blow out unit, direct airflow through front and back louvers as shown. 250 025-A XMT 450 CC/CV TM-257 220 Page 63...
The following is a list of all diagrams for models covered by this manual. Model Serial Or Style Number Circuit Diagram Wiring Diagram XMT 450 CC/CV 400 Volt MC100104A and following 256 909-A 256 916-C 256 497-B ♦♦ Circuit Board PC1 MC100104A and following 202 847-C ♦♦...
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Figure 12-1. Circuit Diagram For 400 Volt Models Effective With MC100104A And Following TM-257 220 Page 66 XMT 450 CC/CV...
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TM-257 220B 2015−03 Eff w/Serial Number MC100104A Processes Multiprocess Welding Description Arc Welding Power Source XMT 450 CC/CV (400 Volt Model) CE Eff w/MC100104A And Following For OM-257 220 Revisions A Thru H Visit our website at www.MillerWelds.com...
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+When ordering a component originally displaying a precautionary label, the label should also be ordered. To maintain the factory original performance of your equipment, use only Manufacturer’s Suggested Replacement Parts. Model and serial number required when ordering parts from your local distributor. XMT 450 CC/CV TM-257 220 Page 78...
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