| Belt pull and torque
The belt pull and torque values given in this catalogue are based on the motor reaching its normal nominal operating condition like speed, temperature etc.
Belt speed
The exact belt speed can deviate by ±10% of the nominal belt speed shown. Exact information regarding the actual belt speed for special applications are available on
request. Please note that a rubber lagged drum motor will have a higher speed than quoted in the catalogue due to the larger diameter. The exact belt speed of single-phase motors
can deviate by plus 10% to minus 20%.
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Motorised Pulleys with mechanical backstop
Motorised Pulleys fitted with mechanical backstops are used for inclined belt conveyors to prevent run-back of the belt should power failure occur. The backstop is built into the
drum motor and is mounted on the rotor shaft. The mechanical backstop works in one direction only and, unless otherwise stated, supplied from the factory with a clockwise rotation
when viewed from the terminal box end of the pulley.
Motorised Pulleys with electromagnetic brake
Motorised Pulleys with electromagnetic brakes are intended for use on conveyors where automatic braking is required in one, or both directions. The electromagnetic brake is a
spring, applied brake and it is connected to the rotor shaft. In a de-energised condition - power switched off - the springs press against
• An armature disc,
• A friction lined disc and
• the brake flange of the motor
And the rectifier and the brake coil are both disconnected. When power is switched on, a magnetic field is built up. The armature disc is attracted (pulled) against the springs
resulting in no friction between
• the armature disc,
• the friction line disc and
• the brake flange.
The brake is now released and the rotor shaft is then able to rotate freely. A rectifier must be used.
Motorised Pulleys with special manufacture
Motorised Pulleys with special power; diameter, widths, speeds, voltages or frequencies deviating from the standard programme can be supplied at extra cost and perhaps longer
delivery time. The stated minimum widths in the range cannot be reduced.
Thermal protector
The thermal protector is a heat sensitive switch built into the motor windings which disconnects the control power should the motor overheat. All three phase motors are supplied
with a thermal protector as standard. The thermal protector must be connected in series with a magnetic coil/relay device and contactor. The thermal protector will reset
automatically when the motor winding temperature returns to a safe level. The thermal protector is based on a bi-metallic switch. The permissible current is 2.5 amps and the
voltage is 230 V.
Note: When the thermal protector switch or other safety devices are activated, check for the cause before restarting the system. Frequent activation of the system can cause
burnout of the windings. In such a case please contact Interroll.
Motorised Pulleys with rubber lagging
Plain or profiled lagging in normal black or white food quality is available. The lagging is normally cold vulcanised (glued) but can be hot vulcanised for high power/high
temperature applications and for drum motors with insulation class "H".
Note: All Motorised Pulley specifications are given according to the standard pulley without rubber lagging. In cases where the Motorised Pulley is to be rubber lagged by the user
it is necessary to refer to Interroll in order to avoid heat dissipation problems and to keep its guarantee. Please also note the speed change when using rubber lagged
pulleys.
Partial rubber lagging
To enable us to deliver lagged, Motorised Pulleys with relatively high powers, we offer partial rubber lagging. For this we use a specially developed shell that has a thicker
central third. The outer two thirds are lagged and are flush with the central third, which remains unlagged and is in constant contact with the belt offering similar heat
dissipation characteristics to standard Motorised Pulleys.
Single-phase execution
Single-phase execution windings are manufactured with a starter winding to overcome high starting torque. The motor must therefore operate with a starting capacitor, a running
capacitor and a relay, which automatically disconnects the starter winding, and the starting capacitor once the rated torque is reached.
Without a starting capacitor, the starting torque is about 70% of the nominal torque listed in the catalogue. Singlephase motors are delivered with running capacitor only.
Starting capacitors are on request.
Certificates of approval/recognition
Motorised Pulleys can be supplied where required in accordance with CSA standard specification.
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