Electrical Service; Preferred Service; Alternate Service - Siemens SINUMERIK 840D Maintenance Manual

FADAL MACHINING CENTERS
2.6.4 ELECTRICAL
SERVICE
2.6.5 PREFERRED
SERVICE
2.6.6 ALTERNATE
SERVICE
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4. Turn off the VMC and measure the ground voltages (AC and DC) again. Record
these readings. Voltages should be OV to .005V.
5. Voltages (AC or DC) across the ground wire will cause false resistance readings. If
the ground voltages with VMC off are 0 (.005VAC max.), set meter to ohms and
measure resistance between VMC ground bus and power distribution enclosure.
Resistance measurement should be less than twice the resistance measured in
step 1. (If resistance is negative (due to a ground current), reverse meter leads and
average the two readings.)
WARNING!
Electrical installation of machine must be done by a qualified electrician.
1. The total connected load should not exceed 75% of the panel rating, allowing for
the VMC load. Refer to the Electrical Rating Plaque for full load current.
2. If other CNC equipment, motor controllers, motors or electric-discharge lighting
(fluorescent, mercury vapor, metal-halide, high and low pressure sodium) are
connected to the same panel, the connected load should not exceed 50% of the
panels rated capacity.
3. Prior to the installation of the VMC, the panel should be measured for average and
peak loads across the three phases.
WARNING!
The VMC must NOT be installed on a panel where the measured surge demand
current exceeds the panel's supply amplitude.
The VMC should be supplied by a dedicated circuit connected directly to the Service
Entrance panel.
The VMC may be supplied by a dedicated circuit connected directly to the local branch
panel.
PRE-INSTALLATION PROCEDURES MAN-0126_R1