TORSIONAL VIBRATION
Torsional vibrations are generated in all rotating shaft
systems. In some cases, the amplitude of these vibrations at
critical speeds may cause damage to either the generator, its
driver, or both. It is therefore necessary to examine the
torsional vibration effect on the entire rotating system. IT IS
THE RESPONSIBILITY OF THE GENERATOR SET ASSEM-
BLER TO ASSURE THE TORSIONAL COMPATIBILITY OF
THE GENERATOR AND ITS DRIVER. Drawings showing
pertinent dimensions and weights of the rotating assembly
will be supplied by Marathon Electric upon request.
ENVIRONMENTAL CONSIDERATIONS
The MagnaPLUS
®
generator is designed for heavy duty
industrial applications; however, dirt, moisture, heat and
vibration are enemies of rotating electrical machinery.
Excessive exposure to the elements may shorten generator
life. The temperature of the cooling air entering the intake
openings of the generator should not exceed the ambient
temperature shown on the generator’s nameplate. Generators
intended for outdoor application should be protected with
housings having adequate ventilation. Although the standard
insulation systems are moisture and humidity resistant, space
heaters are recommended for extreme conditions. If the
generator is to be installed in an area where blowing sand
and dust are present, the enclosure should be fitted with
filters. Filters reduce erosion on the generator's insulation by
blocking high velocity abrasive particles generated by the flow
of cooling air through the generator. Consult the factory for
appropriate filters and generator deratings required.
WIRING CONNECTIONS
Wiring of the generator and accessories should be
done in accordance with good electrical practices.
Follow government, industry and association
standards.
The generator conduit box construction allows cable entry
from multiple sides. A hole saw or other appropriate tool may
be used to provide for conduit entrance. Protect the interior of
the generator from shavings when drilling or sawing. An
approved connector must be used in conjunction with the
conduit. To minimize the transmission of vibration, it is
essential that flexible conduit be used for all electrical
entrance to the generator conduit box.
All MagnaPLUS
®
generators are equipped with link boards
(terminal strips) for both internal and external connections. All
connections made to the studs of the link board should be
made with high quality ring terminals. Ring terminal sizes are:
6 mm (280 Series Frames) and 10 mm (360 and 430 Series
Frames). Torque link board connections to the
following specifications: 280 frame -- 5.4 NM (4 Ft Lb); 360 &
430 frame -- 27 NM (20 Ft Lb).
Refer to the connection diagram supplied with the generator
and / or the proper diagrams shown in this manual. Install all
inter component and external wiring in accordance with
national and local electrical codes. The neutral in the
following connection diagrams shown below may be either
grounded (earthed) or left above ground potential (floating).
See national and local codes and / or the system distribution
wiring schematic diagram for the proper connection of the
neutral.
The following connection diagrams are shown for twelve
lead generators. Ten lead generators have the same
terminal designations except for leads T10, T11, and T12.
These three leads are internally connected inside the
generator and brought out as a single lead (T0). Ten lead
generators can only be connected in a wye configuration.
6
HIGH (SERIES) WYE CONNECTION
