End Caps

Sparks Belting motorized pulleys are supplied with press-fit or bolt-on end caps for easier servicing. The housings are manufactured from seawater-resistant aluminum; 316 stainless steel is also available.

Shaft Seal
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.

Protection Class
All Sparks Belting motorized pulleys are protected to IP66 in accordance with VDE0470 and therefore suitable for applications requiring high-pressure wash downs. 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.

Drum Shell
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.

Electric Motor
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 +105°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, 220V 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 step-less 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.

Electrical Connections
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.

electrical connections

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 Sparks Belting.

Only high-quality, single row or double row precision ball bearings and needle bearings are used.

Casing Parts
Gearbox, stator casing and rear flange are made of high-density aluminum alloy. In high torque applications, ductile iron components are used.

Back Stop
A backstop bearing can be placed in the drum motor to prevent product roll back. This option is used primarily on inclined belt conveyors.

Electromagnetic Brake
The brake operates on a DC supply via a DC rectifier (supplied). It is a single disc type fixed to the rotor. When the motor is switched off, or in the case of power failure, the brake will automatically engage and hold the drum motor until the motor is re-started.

Thermal Overload Protection
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 105°F, or when pulleys will be used without a belt, contact Sparks Belting. Sparks Belting motorized pulleys are designed principally for belt conveyors. 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 recommendations.

Rubber Lagging
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.

Options Overview

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