NORD Drivesystems Berges-VG - Manual (Page 11)

3.1.2 General description
ƒ The RGAE are supplied as a variable-speed gear attachment unit, of base or flange
design, or with reduction gear and are suitable for all conventional installation positions.
ƒ The variable-speed gear casings consits of aluminium and have a symmetrical
design. They are sturdy, vibration-damping and designed for continuous operation.
ƒ The variable-speed pulleys ( regulating and spring pulley R and F ) have a wedge-
shaped symmetrical cross-section with a very low mass.
ƒ All shafts are mounted in rolling-contact bearings and are packed with rolling-contact
bearing grease for lifetime lubrication.
ƒ The reduction gearboxes are adequately dimensioned helical -, worm-, bevel - or
helical shaft mount. Gearboxes or contrate worm gears of base, flange or hollow-shaft
design. The rugged cast casings are vibration-damping and suitable for rough indus-
trial use.
ƒ The variable-speed gearboxes normally require no additional cooling. Venti-
lation slots and the large surface area suffice to dissipate the heat loss if convection
is unobstructed.
3.1.3 Mode of operation
( see Figures 3 and 4, Page 12 )
ƒ The three-phase motor ( Item 8 ) drives the mechanically adjustable regulation pulley
R ( Item 1 ). This drives the spring-loaded spring pulley F ( Item 2 ) which is arranged
on the drive shaft of the gear flange GFL ( Item 7 resp. Item 7.1, Figure 5, Page 13 )
or the drive shaft of the reduction gear ( Item 5 ), via the wide V-belt ( Item 6 ). Depen-
ding on gearbox type, the gearbox is attached either directly to one of the two casing
halves ( Item 3 / Item 4 ) or using the gear flange GFL resp. Gear base GTF.
( Item 7.1 resp. 7.2 )
ƒ The rotational speed is adjusted by the adjustment device ( Items 10, 11, 12 ) by
shiftingthe moving running surface of the mechanically adjustable regulating pulley R
in axial direction by turning the handwheel resp. Operating the variable-speed motor.
A rotational speed indication ( option ) is provided by the position indicator in the
scale handwheel or electrically by means of the pulse generator and indictor.
3.2 Operating conditions
ƒ The operating conditions, such as temperature ranges and installation altitudes, are
defined by the drive motor and the reduction gearbox ( see the relevant Operating
Instruction ). The max. permitted operating temperature of the variable-speed drive
is 80°C at normal operation and an ambient temperature of -20°C to +40°C to be
measured at the outside of the VG housing.
11
Technical Data