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Welding transformers

Welding transformers ISOMATIC Lab successfully developed and brought to market a family of ISO 10656 transgun transformers designed for integration in welding robots and machines.

The iron core consists of C-cores wound from high quality grain-oriented electrical steel. Cooling water flows through the secondary winding, made from rectangular copper tube. Here are manufacturing details.

The transformers range from 25 kVA to 103 kVA, delivering short circuit currents of up to 67kA at voltages of up to 13.5 and can be delivered for all practical mains supply voltages - 380, 400, 415, 440, 480, 500 and 550V, 50 or 60 Hz. Other primary voltages are available on reguest.

All transformers have built in current sensing toroids, with an output of 150mV/1kA. Two thermoswitches are fitted, one monitoring primary, and one secondary temperature. They are set at: primary 140 degree C, secondary 80 degree C.

The transformers have been tested by independent test authorities and meet the requirements laid down by ISO/TC 44/SC6 in ISO10656 and related international standards.

Technical specifications for the transformers are given below. There are two frame sizes, H & J. Transformers rated from 25kVA to 41kVA are produced in the H size. All other transformers are produced in the J size. The fixing dimensions are given on the technical drawing and the table below. All J size transformers are interchangeable and all secondary connection pads on H & J transformers are identical, allowing shunts and busbars to be standard.

Primary connection terminal arrangementd are common for all sizes from 25kVA to 61kVA. Connection for 76kVA and 103kVA are larger, to permit connection of larger dimension primary cables.

Different aluminium alloy connection boxes can be offered, either with direct connection through Multi-contact type plugs or cable glands. Special boxes can be manufactured when needed by the customer.

Main parameters of Isomatic's ISO 10656 transgun transformers:

(25 kVA & 48 kVA versions also available to order)
Type ITF32
(H size)
(H size)
(J size)
(J size)
(J size)
(J size)
Order No
380V - 50/60Hz ITF32380P ITF36380P ITF54380P ITF61380P ITF76380P ITF103380P
400V - 50/60Hz ITF32400P ITF36400P ITF54400P ITF61400P ITF76400P ITF103400P
415V - 50/60Hz ITF32415P ITF36415P ITF54415P ITF61415P ITF76415P ITF103415P
440V - 50/60Hz ITF32440P ITF36440P ITF54440P ITF61440P ITF76440P ITF103440P
480V - 50/60Hz ITF32480P ITF36480P ITF54480P ITF61480P ITF76480P ITF103480P
500V - 50/60Hz ITF32500P ITF36500P ITF54500P ITF61500P ITF76500P ITF103500P
550V - 50/60Hz ITF32550P ITF36550P ITF54550P ITF61550P ITF76550P ITF103550P
Continuous rating Sp [kVA] 22.5 25.2 38 43 53.7 73
Standard 50% Rating S50 [kVA] 32 36 54 61 76 103
No-load secondary Voltage U20 [V] 5.6 6.3 7.1 8.0 10 13.5
Continuous secondary current I2p [kA] 4.0 4.0 5.4 5.4 5.4 5.4
Height [mm] 245 265 285 310 370 460
Size [mm] H (106 x 150) J (125 x 160)
Electrical connection Spacing E [mm] 26 26 26 26 26/45 45
Depth [mm] 8 8 8 8 8/10 10
Screw thread [] M6 M6 M6 M6 M6/M8 M8
Mass [kg] 21 25 31 36 40 55
Colour purple blue green grey yellow brown
Measuring coil

150 mV/kA ± 1.5% at 1 kOhm resistance

Primary thermoswitch

Cut-off temperature 140 C ± 6 C

Secondary thermoswitch Cut-off temperature 80 C ± 6 C

Due to their small physical size and high output characteristics, the transformers have uses in special machine applications as well as robot and manual welding guns, minimizing stray magnetic fields and impedance thus allowing to achieve optimum electrical energy transfer.

Thousands of ISOMATIC transformers are welding car bodies day and night at Ford, General Motors, DaimlerChrysler and other famous car manifacturers.

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