Miller Auto-Continuum 350, Owner'S Manual

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OM-273473 Page 30
6-5. Earth Grounding
When using a robot or any programmable controls, it is necessary to connect equipment to a good earth ground. Grounding helps eliminate electrically
generated noise from corrupting processing data or the potential damage to sensitive electrical components. Electrical noise is an issue anytime high
frequency TIG equipment or inverter type power supplies are used in the area. A method for checking for a good earth ground is shown below. Also, be
sure to a good connection to the earth ground.
Earth Ground
Being Measured
100W Light Bulb
110 Volts AC
Neutral
1 Volt 1
W
V
Measuring Facility (Earth) Ground Resistance
The resistance of an earth ground can be measured using a 100W light bulb, an ac voltmeter and a 110 volts AC electrical drop. As shown in the circuit,
the 110 volts AC (hot) supply and the 100W light bulb approximate a 1 ampere current source when the light bulb circuit is completed by connecting to
the earth ground. The AC voltmeter, referenced to the AC neutral line, can then be used to measure the voltage rise due to the 1 ampere current source
through earth ground. Each volt of rise on the earth ground represents 1 ohm of resistance. A resistance of less than 10 ohms at the earth ground should
be adequate.