PROJECTION CUM SPOT WELDING MACHINE

Product Description

MACHINE DESCRIPTION

KVA RATING:

The transformer will be air cooled step down 100 kVA 2 Phase 440 VAC 50 % duty cycle with 4 taps for variable voltage.

MACHINE BODY

Reinforced fabricated steel structure with louvered covers for well ventilation. Simply supported type, heavy section fabricated upper and lower arms fitted directly on the machine. Upper arms carries friction or anti-friction ram along with the weld electrode assembly. Lower arm carries the lower weld electrode assembly with ample section bus bar. The upper and lower arm are constructed such a way that even under heavy pneumatic pressure, minimum deflection occurs. Main transformer is housed in the basic body.

WELDING TRANSFORMER

A heavy duty transformer made as per IS - 4804 Part 1 is used as the main power source. Special sandwich construction of coils helps to increase the coupling between the windings and offers maximum efficiency. Primary and secondary conductors are selected to suit the heavy demand current. Copper cooling tubes are brazed throughout the periphery of the secondary segments. Transformer core is made out of cold rolled grain oriented lamination sheets to reduce the core losses. Class F insulation materials used in the transformer help to withstand a temperature of up to 155^oC. The coil assembly is varnished in F 50 varnish and vacuum impregnated. A special thermo switch fitted on the secondary segment helps to cut out the control circuit when the temperature of the winding rises above the safety level, thereby protecting the transformer from overloading.

RAM

Anti friction ram is used for electrode and cylinder attachment with brass bush in which the induction hardened tail or pilot rod will be sliding to properly guide upper electrodes.

PNEUMATIC SYSTEM

The basic pneumatic system consists of a pneumatic double acting cylinder, solenoid valve of 4 way 5 port, filter, lubricator, regulator, gauge and foot operating initiating switch for solenoid coil. The precision honed and lapped pneumatic cylinder, both sides cushioned, is directly connected to the ram with the help of coupling. Electrode force is varied by means of the air regulator knob.

All the current carrying components are internally water cooled and hence no external water spraying is required as in the conventional machines. The upper and lower bus bars are provided with built in water jackets.

ELECTRONIC CONTROL SYSTEM

The Micro Processor Control is housed in a desk type control cabinet, which is normally suited for separate floor mounting. All the control knobs are housed on the desk behind a transparent acrylic guard door to prevent misuse by unauthorized persons. The control circuits used in the system are based on the latest technology of IC’s, transistors and thyristors. For easy operation and maintenance, all cards are modular type and wherever necessary, sturdy plugs and sockets are used for easy service. The control and foot switch circuit is connected to a low, safe and isolated control voltage.

The foot switch will initiate the solenoid valve of the pneumatic cylinder and simultaneously the squeeze timer will energize the weld control, after the time set (1 - 100 cycles). A fully synchronous digital timer of "0 - 100 cycles ON " and "0 - 100 cycles OFF " will feed exact "ON - Of" pulses to the heat control card. The heat control card generates pulses, which triggers the thyristor switch. The current of the welding transformer can be adjusted from 5% to 100% by means of the phase shift firing of the thyristor switch.

UPPER AND LOWER WELD ELECTRODE ASSEMBLY

Consists of copper alloy weld electrodes of suitable section of hardness 68 Rockwel B scale, weld electrode holders, high percentage of copper content phosphor bronze bushing and water cooled holders of ample section copper alloy casting.

POWER ELECTRONIC CONTROL SYSTEM

The thyristors, matching the KVA of the transformer connected, in inverse parallel constitute the thyristor switch. The thyristor switch is mounted on an ample water cooled heat sink section to facilitate smooth and efficient current switching to the welding transformer for continuous welding operation, without appreciable change in the heat sink temperature. Protection devices like thyrectors for high voltage transcients and thermoswitch for heat sink temperature control is incorporated. Hold timer is provided to stop the welding current, before separation of welding wheels. The range of timer is 1 - 100 cycles.

WATER COOLING SYSTEM

All the current carrying components are internally water cooled and hence no external water spraying is required as in the conventional machines. The upper and lower bus bars are provided with built in water jackets. Water Pump will also be provided with the machine.

Spot Welding Machine Features :

The Current of the Transformer will be adjustable from 5% to 100 % by thyristor switch

Machine Specification :