Manual for Induction Motors and Generators
Safety Instructions -
3
3BFP 000 050 R0101 REV E
case of sleeve-bearing machines, observe time-limit for oil-change and if equipped with oil
supply system make sure the system is working.
7. Maintenance and servicing
Follow the manufacturer's operating instructions. For further details, see the comprehensive
User´s Manual. Preserve these safety instructions!
8. Frequency converter
In frequency converter applications motor frame external earthing must be used for equalising
the potential between the motor frame and the driven machine, unless the two machines are
mounted on the same metallic base. For motor frame sizes over IEC 280, use 0.75 x 70 mm flat
conductor or at least two 50 mm² round conductors. The distance of the round conductors must
be at least 150 mm from each other.
This arrangement has no electrical safety function; the purpose is to equalise the potentials.
When the motor and the gearbox are mounted on a common steel fundament, no potential
equalisation is required.
To comply with EMC-requirements, use only cables and connectors approved for this purpose.
(See instruction for frequency converters.)
Additional Safety Instructions for Permanent Magnet Synchronous Machines
Electrical connection and operation
When the machine shaft is rotating, a permanent magnet synchronous machine induces voltage
to the terminals. The induced voltage is proportional to the rotational speed, and can be
hazardous even at low speeds. Prevent any rotation of the shaft before opening the terminal box
and/or working at the unprotected terminals.
WARNING: The terminals of a machine with frequency converter supply may be energized
even when the machine is at a standstill.
WARNING: Beware of reverse-power when working at the supply system.
WARNING: Do not exceed the maximum allowed speed of the machine. See product specific
manuals.
Potential equalisation
Plate/strip
Cables/wires
Driven machinery
V1
U1 W1
PE
3~ M
0.75 mm
70 mm
> 150 mm
min 50 mm