Jenkins Electric Motors SA FAQ


Frequently Asked Questions
Below are some of the frequently asked questions that may help you with the Jenkins Electric Motors products, should you need any further information please contact our sales team. Tel: (011) 4500575

What is axial load ?
Axial load is a force on the output shaft into or out of the motor or gearmotor. It is shown as Fa in the diagram above. Exceeding the allowable axial load for a motor or gearmotor will cause premature wear on output shaft bearings and gearing.

What is radial load ?
Radial load is a force pushing or pulling the side of the output shaft. It is shown as Fr above. Exceeding the allowable radial load for a motor or gearmotor will cause premature wear of output shaft bearings and gearing and could cause the shaft to break. Fr may be the result of a weight on the shaft, belt tension or torque transmitted through a belt, chain, gear, or certain flexible couplings. A permissible radial load (Fr) is shown for each motor and gearmotor. In calculating these values, the following assumptions were made:

  • The radial load is the worst case direction, i.e. pushing or pulling the shaft sideways.
  • The motor or gearmotor is delivering rated torque.
  • The radial load was applied at distance “d” from the hub or mounting surface. Higher radial loads may be applied closer in on the shaft. Lower radial loads are permitted further out on the shaft.

Flexible couplings are often used to avoid radial load. Most flexible couplings are designed so that they do not transmit radial load, however this should be verified with the coupling manufacturer.

Can more than one motor be operated from a single control ?
Operation of more than one motor from a single control is not normally recommended. However, when the cost is a primary concern, a multiple motor/single control system with either permanent magnet motors and control, or 3 phase motors and control, may be successfully implemented. More than one permanent magnet motor may be operated with a single permanent magnet control as long as the sum of the motor currents does not exceed the rated output current of the controller. Comprehensive testing is recommended because this type of system may produce fluctuation or drifting speed output. More than one three phase motor may be operated with a single three phase control. Motor speeds should not fluctuate as long as the motors are not overloaded and the sum of the motor currents does not exceed the rated output current control.

Which gearheads are self-locking ?
Parrallel shift gearheads and right angle gearheads with low ratios are generally not considered to be “Self-locking”. Right angle gearheads with ratios greater than 25:1 are often considered to be “Self-locking”. They will resist movement up to their torque rating. As the gearing nears the end of its useful life or it is subjected to overload conditions, it may wear to the point where it is no longer “Self-locking”. Self-locking gearing is not a recommended method for preventing movement in applications where the movement may cause injury or damage. An external brake is recommended for those applications.

What is meant by the term self-locking ?
Self-locking refers to the tendency of some gearing to resist movement when the gearmotor is at rest and the load is attempting to move. An example of this is a load on a conveyer belt trying to drive the system backwards.

What is IP 54 ?
The IP number is an international system for rating enclosures. An IP 54 is for protection against dust and splashing liquids.

Is an adjustable speed system ever appropriate for a single speed application ?
Adjustable speed systems are sometimes appropriate for single speed applications. If the desired speed is not known or offered in a single speed product, an adjustable speed system may be set to a desired speed.

Can single speed motors and gearmotors ever be operated as variable speed ?
Three phase and some Permanent Split Capacitor designs may be operated as variable speed with our frequency inverter. Commutator motors can be operated as variable speed using a thyristor controller.

Can continuous duty motors/gearmotors be used intermittently ?
All rated torques shown in this catalogue are for continuous operation. Continuous duty products can be used intermittently. Operation at loads higher than the nameplate ratings is possible for short periods as long as there are rest periods for cooling. Loads must not exceed the mechanical rating for the gears without consulting our sales engineers. The temperature of the motor should be monitored during testing to make sure it is not overheating.

Which motors/gearmotors are electrically reversible ?
All motors and gearmotors in this catalogue are reversible. (except shaded pole). Some require a full stop before reversing.