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ENTRON Controls, LLC. 700230D
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2.1 Cooling Water
Be sure power to an electronic contactor is turned off when water is turned off.
With a voltage applied, most water will ionize and begin to conduct current between points of
high differential voltages. This current is sufficient to heat the water past the boiling point,
creating steam and possibly causing the rubber hose to burst. The water spraying over the
high voltage circuit can cause considerable damage to the contactor and, most likely, the
control circuitry as well. Never use metallic or other conductive tubing to plumb a water-cooled re-
sistance welding contactor. Heater hose has a very high carbon content and should not be
used for contactor plumbing. A low carbon, reinforced hose (such as the hose originally sup-
plied with the unit), no less than 18" long, must be used to connect the Heatsinks to each oth-
er and to the bulkhead fitting on the inside wall of the cabinet.
The 1200A modular water-cooled SCR Contactor is electrically isolated from electrical circuit
within the contactor section. No minimum length of water hose is required for electrical isolation
of the contactor. It is still recommended to turn power off when control is not in use.
For all water-cooled Heatsinks, be sure water is turned ON before placing welder in operation.
An open drain is recommended for best operation. If a closed return system is used, be
sure return line is properly sized so that back pressure will not reduce water flow be-
low recommendations. A sight flow indicator is recommended.
WATER OFF—POWER OFF
POWER ON—WATER ON
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