Find an answer to some frequently asked questions about our range of products. From Technical specifications to operational issues to clarification of terms.

Just Ask

No matter what enquiry you have we will endeavour to find a satisfactory answer for you. If you’re unable to find an appropriate answer in the FAQ section please contact our sales staff for a prompt response.

  1. Does it matter which shaft I use as my input?
  2. As standard the units are supplied with the shaft 1 or sometimes referred to as A as the input. It is also the shaft, which is housed, in an extended housing on ratios above 1.5:1 on the range N. When using a 1:1 ratio gearbox it does not matter which shaft is used as the input as the speed will remain constant. However it is important to ensure that the correct shaft is used on higher ratios other wise the unit will end up increasing the speed.

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  3. Can I use the bevel gearboxes as speed increasers?
  4. All units can be used as speed increasers, by inputting on the output side of the gearbox, however it is important to check that the unit can handle the power and speed. When using as an increaser it is usually the input speed that is important, do not exceed the catalogue recommended maximum speed. Special units are available where the pinion can be put on the through shaft so that two outputs increase the speed, please request details on this.

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  5. When I look at the bevel gearbox shaft arrangement/rotational diagrams, how should I interpret these?
  6. When looking at the bevel gearbox shaft arrangement diagrams, the gearboxes are shown in plan view, but the actual rotational arrows are representative of the output shaft rotations viewed from the end of the shaft looking directly at it. A good visualisation of the gear arrangement can also be seen on the 3D CAD models for the Range-N bevel gearboxes configurable online. You can view the model with a transparent housing just to check gear orientation.

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  7. Is there a safety margin built into the power/torque figures for the bevel gearboxes?
  8. There are safety margins built into the figures, but the tabulated figures should not be exceeded, so that the units work for efficiently and correctly for their intended life time.

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  9. What is the best method of fitting couplings to the shafts of a bevel gearbox?
  10. It is very tempting to tap couplings onto the shafts using a hide mallet, but this is a method which is not recommend, as a sharp blow to the shaft end can damage the bearings. The preferred method of fitting is to use the tapped hole in the end of the shaft and a bar with a hole drilled through it. Put the correct size screw through the hole and wind the coupling on.

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  11. Does my bevel gearbox need a vent?
  12. Some of the units in the ranges are supplied with a vent, others are not.

    The Range N up to and including the P140 / X140 do not have breathers fitted as standard. All other units are either supplied with breathers pre-fitted, or will be supplied with the unit to be fitted after oil fill. If the unit is to run at very high speeds, then we would suggest fitting a breather, please consult us if you intend to run a unit extremely fast.

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  13. Are the bevel gearboxes supplied filled with oil?
  14. Range-P is supplied filled with oil and sealed for life.

    Range-N is supplied dry (no lubricant).

    Range-U lubrication defined on project basis.

    All other units will require filling with oil prior to installation. Note - For low speed applications (250 rpm input speed and below) gearboxes may be recommended to have semi-fluid or grease lubrication. Consult Power Jacks for advice.

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  15. How often should I change the oil in the bevel gearboxes?
  16. This depends on how often the unit is run and the type of oil that has been supplied with the unit (if pre-filled).

    Range P units are sealed for life and require no maintenance.

    For all other units we recommend changing the oil every six months or 2,500 operating hours.

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  17. Is it possible to fill the bevel gearboxes with grease?
  18. We recommend filling the units with grease or semi-fluid grease if the units are operating at speeds of 250rpm or below.

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  19. What is the maximum recommended case temperature for a bevel gearbox?
  20. The case temperature must not exceed 80°C.

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  21. Can you manufacturer me a bevel gearbox with special shafts, case material etc?
  22. We can adapt a unit to your specification, but only from the Range N & U, the design of these units are suited to adaptability.

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  23. Some of the bevel gearboxes have a maximum speed, how is this calculated?
  24. The maximum pinion speed is based upon a pitch line velocity of 762M/min (2500ft/min)

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  25. How efficient are spiral bevel gearboxes?
  26. The units efficiency ranges from 95 to 98%

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  27. I notice that the noise of the unit and case temperature reduce when the units are fully operational.
  28. It is known that the noise and temperature levels do drop when the units are under load, this is due to the bearings and gears working rather than running idle.

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  29. Are spares available for the various ranges for bevel gearboxes?
  30. The range P units are sealed for life and not suited for economic repair. They should be replaced instead. The Range-N and Range-U can be repaired or spares fitted, although it is worth noting that if all internal components need replacing then it would be cheaper to purchase new units. If units need repairing we would recommend returning them to the factory, where they can be rebuilt with the correct backlash and alignment.

    When disposing of gearboxes and lubricant please do so in an environmentally responsible manner.

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