Case Study - Power Savings; an Added Bonus from CBC. David Brown Industrial Gearbox.

10 February, 2016

Author - Tony Voiklis Power Transmission Technical Specialist

Power Savings; an Added Bonus from CBC.

Case Study - Power Transmissions by David Brown Industrial Gearbox

Author: Tony Voiklis Power Transmission Technical Specialist

CBC specializes in designing and supplying Power Transmission Drives and industrial gearboxes to a wide variety of industries. Not only have they successfully offered industrial sites significant purchase cost over rebuild cost savings, but they have also offered dramatic power saving costs through their ability to redesign current industrial gearboxes to more efficient gearbox options.

The following provides an example from a South Australian mining site where significant savings were realised and quantified for reduced downtime, purchase price over rebuild costs, power saving, and environmental, Carbon Tax, saving.

Background on Industrial Gearbox Upgrade

CBC received advice from the customer that the main drive gearbox on the Number one Primary Conveyor had catastrophically failed. The failure of this industrial gearbox had completely stopped production at this particular facility. CBC was asked by the client to find a replacement industrial gearbox.

The failed gearbox was an outdated David Brown Radicon Worm Wheel type industrial gearbox. This particular model of David Brown industrial gearbox was not popular in modern drive designs due to its high cost and poor efficiency. The supply of this same David Brown gearbox was not possible on a short lead time. The following is a breakdown of the status of delivery and cost.

ItemDelivery TimeCost 
 New David Brown industrial gearbox  15 weeks   AUD $85,000
 Overhaul existing David Brown industrial gearbox  15 weeks   AUD $65,000

CBC Power Transmission technical specialists undertook a full analysis of the drive and found that the industrial gearbox was rated to a maximum of 37.1KW, despite it having a power input of 55KW. While the gearbox had been in place for many years, in recent times a larger motor had been installed to increase output. This had lead to the failure of the drive, which included Worm Wheel gear destruction. Hence, should CBC have been able to supply an identical replacement David Brown industrial gearbox, failure would have reoccurred.

Solution for Industrial Gearbox Upgrade

CBC was able to redesign the drive to accept a Rossi Bevel Helical gearbox. This particular industrial gearbox was lower in cost, and greater in efficiency. More importantly, this particular gearbox had the rated capacity to suit the drive motor. To adapt this drive to the conveyor and expedite installation, CBC also fabricated a drive base plate. The following is a summary of delivery and costs. Summary of delivery and costs is as follows;

 Item Delivery TimeCost 
 New industrial gearbox  3 weeks  AUD $45,600
 Adapter base plate  3 weeks  AUD $5,813
  TOTAL  AUD $51,413

This selection offered twice the mechanical capacity of the previous industrial gearbox, 77KW versus 37.1KW, greater power efficiency, and improved features, such as Air Sentry desiccant breathers.

Summary of Cost of Industrial Gearbox Upgrade

In order to quantify production cost savings, a cost of downtime was required. The only official production cost analysis available for this site was undertaken in 1990. The following therefore, in today’s terms, is considered to be conservative.

The 1990 production at this facility was costed at $6 per tonne. It operates 24 hours a day, five days per week, producing 2000 tonnes per 24 hour day. Therefore:

At $6 per tonne x 2000 tonnes per day = AUD $12,000 per day The customer was able to mitigate some of the downtime loss by having employees take holidays during the period of lost production. In addition, some planned electrical maintenance work, 10 days in total, was able to be brought forward.

Via CBC providing a delivery improvement, this industrial gearbox redesign provided a lead time of three weeks over the best possible alternative option of 15 weeks to rebuild. The saving was: 50 days ( 10 weeks) x $12,000 per day = AUD $600,000.

 Note: Calculations are based upon 10 weeks due to the fact that two weeks of electrical planned work was undertaken during this period as mentioned above.

 In addition, CBC was able to supply the upgraded solution at a lower cost of $51,400 versus the lowest cost alternative option of $65,000. Therefore the purchase cost saving was $65,000 - $51,400 = AUD $13,600

 Further Potential Industrial Gearbox Upgrade Savings

Firstly, if the 15 week option to rebuild the existing industrial gearbox had been undertaken, another catastrophic failure was highly likely, particularly in line with a conveyor jam up, as there was no fail-safe device, such as a fluid coupling, on this particular conveyor. Therefore, the rebuild cost of AUD $65,000 had potentially been saved within the first 12 months.

 Secondly, the Bevel Helical Gearbox upgrade CBC engineered had a power efficiency of 96.5%. The Worm Wheel industrial gearbox that was originally in place had a power efficiency of only 65% when new.

In other words, of the 55KW input power, 35% was being lost with the worm wheel gearing. This meant that the motor had to draw 35% more amps. This was both an additional cost in power consumption and an environment disadvantage via additional green house gas generation.

 As an approximation, to assume a conservative 25% of the 55KW input power was lost, or 13.75KW at the sites average power cost of 0.165KWH, the potential ongoing annual saving on power consumption would be:

13.75KW @ 0.165KWH x 24hrs x 5 days per week x 48 weeks per year = AUD $13,068 per annum

Summary of Industrial Gearbox Upgrade

The cost savings of this particular industrial gearbox upgrade is summarized in the following table.

Savings  Savings Cost
 Production downtime saved  $ 600,000
 Purchase cost saved  $13,600
 Potential saving via avoiding additional failure (annualised)  $65,000
 Potential power consumption saving (annualised estimate)  $13,068
 TOTAL  $ 691,668

CBC redesign and upgrade services on Power Transmission Drives can provide significant options for a variety of savings. CBC has supplied, redesigned, or refurbished industrial gearboxes and other drive components, including brakes. As well as performing redesign and refurbishment on David Brown industrial gearboxes, CBC have also upgraded a wide variety of other brands of gearbox and various gear reducer configurations, quantifying the savings to the customer. These include Flender and Bauer industrial gearboxes, as well as planetary and variable speed drives.

 In addition, CBC industrial gearbox refurbishment services include the following additions and/or upgrades for all types of current gearboxes, offering improved longevity and problem solving.

  •  Air Sentry desiccant breathers for dust or moisture/humidity exclusion.
  • Sensors/Accelerometers for vibration analysis, including cabling and junction boxes to suit site applications and conditions.
  • One Eye magnetic filtration options for exclusion of ferrous particles.
  • Route cause failure analysis reporting.
  • Sealing upgrades for all environments.
  • Thermal insulation options for protection in hostile environments and energy saving.
  • Drive alignment options, including onsite service.
  • Vibration dampening options, including Rosta tensioner.
  • Lubrication upgrades, including premium options for extreme environments via Kluber Lubrication.
  • Perosity sealing of gearbox castings.
  • Oil cooling systems/heat exchangers.
  • Soft start options via Inverters or Fluid Couplings.
  • Lubrication systems, including recirculation and kidney loop.
  • Oil sampling ports.   

Author: Tony Voiklis Power Transmission Technical Specialist