Guidelines for planning the electrical installation 97
the terminals. This can cause additional stress on the motor and motor cable
insulation.
Modern variable speed drives with their fast rising voltage pulses and high
switching frequencies can generate current pulses that flow through the motor
bearings. This can gradually erode the bearing races and rolling elements.
d u /d t filters protect motor insulation system and reduce bearing currents. Common
mode filters mainly reduce bearing currents. Insulated N-end (non-drive end)
bearings protect the motor bearings.
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Requirements tables
These tables show how to select the motor insulation system and when a drive
d u /d t and common mode filters and insulated N-end (non-drive end) motor
bearings are required. Ignoring the requirements or improper installation may
shorten motor life or damage the motor bearings and voids the warranty.