Belting motorized pulleys are supplied with press-fit or bolt-on end caps
for easier servicing. The housings are manufactured from seawater-resistant
aluminum or iron; 304 stainless steel is also available.
The end housings are fitted internally with double lip oil seals and
externally with steel labyrinth seals. This provides excellent protection
against ingress of dust, grit, water and moisture and even high-pressure
cleaning. The steel shafts are fitted with smooth precision wear sleeves
positioned under the double lip oil seals. This prevents wear to the
shaft and seals.
All Sparks Belting motorized pulleys are protected to IP66 in accordance
with VDE0470 and therefore suitable for applications requiring high-pressure
washdowns. For special applications, protection class IP67 with stainless
steel re-greasable labyrinths is also available.
Fixed and variable shafts are manufactured from mild steel and have
identical shaft diameters and shaft flats at both ends. 304 stainless
steel is optional.
The outer drum shell is manufactured from thick-walled mild steel tube
with a machined crowned face to ensure correct belt tracking. If desired,
a metal shell without crowning can be supplied. The drum shell is also
available in 304 stainless steel or, as a low-cost alternative, with
hard chrome surface.
All Sparks Belting motorized pulleys are designed to IEC standards in
accordance with DS 188 IV B1 and VDE 0530 with Insulation Class F standard
(Insulation Class H available upon request). The motor is an asynchronous
squirrel cage induction type. Class F motors are suitable for most applications
with ambient temperatures of +100°F -10°F. For temperatures
above or below this, Class H motors should be specified. In some cases,
Class H motors are recommended where the pulley will be working without
a belt or when fitted with very thick lagging. When in doubt, contact
Sparks Belting for recommendation.
Single-phase motors 110V, can also be supplied as an option whereby
starting torque, drum torque, horsepower, and belt pull are reduced
by only 30%.
Electric motors with windings for special voltages and frequencies
are available upon request.
Sparks Belting motorized pulleys are inverter duty motors and can
therefore have a stepless speed control in combination with static frequency
converters in the range from 30 to 60 Hz. For speed variations outside
this range, contact Sparks Belting.
Standard motorized pulleys fitted with a terminal box can normally be
connected for single or dual voltage access.
Pulleys with fitted cables are normally supplied for one voltage only.
Dual voltage cable is available upon request at extra cost.
Only two-stage and three-stage gear boxes are used. All gears are made
from high-grade steel which are hardened and polished. The belt speeds
given in the catalog are nominal. If exact speeds are required, contact
Only high-quality, single row or double row precision ball bearings
and needle bearings are used.
Gearbox, stator casing and rear flange are made of high-density aluminum
alloy. In high torque applications, ductile iron components are used.
A backstop bearing can be placed in the drum motor to prevent product
roll back. This option is used primarily on inclined belt conveyors.
Sparks Belting motorized pulleys are equipped with thermal protection
(TF) in the stator of windings. This prevents motor failure due to overheating
or overloading. The TF will automatically re-set, but the motor must
be re-started manually. (Not available on 3.19" dia. pulley)
The cooling of the electric motor and the lubrication of the transmission
parts and ball bearings is effected by means of SAE 90 gear oil. The
drum motor is factory oil-filled before delivery. For applications with
temperatures below -10°F or above 100°F, or when pulleys will
be used without a belt, contact Sparks Belting. Sparks Belting motorized
pulleys are designed principally for belt converyors. The angle between
the longitudinal axis of the pulley and the horizontal axis must not
exceed 5°. If it does, lubrication may be insufficient and damage
to the unit could occur. See Installation
& Maintenance for oil fill requirements and installation/maintenance
To achieve proper friction between the drum face and conveyor belt,
Sparks Belting offers lagging made of hot or cold-vulcanized 1/8", 1/4"
plain black or white, oil & fat resistant rubber, or hot vulcanized
rubber. Other types of materials (such as neoprene, silicone, pvc, etc.)
and patterns (such as diamond or grooved) are available.
Rubber lagging can cause thermal overload. To prevent this, the required
power should be multiplied by a factor of 1.2. Due to the increased
thickness of rubber lagging, the belt speed will increase accordingly.
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