Feature Drives & transmissions
Repair or replace? How to deal with drive failure
Making the right choice between repairing or replacing an electronic drive can make significant savings of time and money, says Vic Harris of Eriks
hoosing whether to repair or replace a drive isn’t such a clear cut decision as you might think. On the face of it, purchasing a new unit may seem the clear favourite, while a repair could appear to be the less preferable but cheaper option. Neither of those views are necessarily the case; it all depends on the circum- stances and it pays to look at the avail- able options in a little more detail to make a truly informed decision. Before taking a closer look at those options, it is necessary to take a step back and look at the two most common causes of drive failure: overheating and pollution. Poorly specified cabinets, designed without adequate ventilation or any allowance made for high ambient temperatures, are a root cause of overheating. Likewise, a high level of dust and other airborne pollutants can be prob- lematic, since these contaminants can enter the drive casing and cause the fan to fail by damaging the bearings. The graphs opposite represent the temperature changes inside two drive cabinets, as measured by Eriks to help prevent future failure.
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So, the operating environment plays a large part in defining the lifespan of a drive and, when you consider that such environmental factors can reduce that lifespan by half, it is clear that making the right decisions at the point of installation can save a lot of time and money further down the line. However, even well protected equip- ment has a finite lifespan; for instance, fans and capacitors naturally degrade and will eventually need replacing. So what should be done when elec- tronic drives fail? Repair or replace? With drives below 4kW, the decision is simple: commodity price and brand interchangability make it more economical to replace a unit. At the opposite end of the range, there is rarely a dilemma when drives of 75kW fail as they are modular, allowing for easy component replacement rather than substitution of a new unit, and, in any case, these drives are often pur- chased with maintenance contracts. However, where units that fall in
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between those ratings are concerned, there may be a decision to make, and not only one based on cost. For example, a new drive unit may offer enhanced functionality but how important is that enhanced functional- ity balanced against the possible complications of integrating the new unit into your existing system? Taking a broader view of system health, it may be wise to opt for a repair to establish whether there are faults outside the drive unit. The fitting of a replacement drive may remove the problems that were caused by failures within the previous unit but a drive repair can identify the root cause of failure and may reveal an external problem, which could save the operator consid- erable time and expense.
It is also important to consider that, while a new unit may bring peace of mind and a new guarantee, the same can be said for a repair. Eriks drive repairs are supported by a 12-month in-service guarantee and, in addition to gaining information on the root cause of failure, the operator will benefit from an engineer’s advice on how to
The decision to repair or replace drives should depend on the circumstances and it pays to look at all the options to find the most cost-effective solution
The graphs below show the temperature
changes inside two drive cabinets as measured by Eriks to help prevent drive failure
avoid a recurrence of similar problems in the future. When the cost of drive repair can be as little as 50 per cent of that required to purchase a new unit with the same estimated lifespan – 40,000 hours (MTBF), or five years in continuous operation – it becomes clear a repair is not to be automatically considered as the second best option. However, whether repaired or replaced, your drive will only reach its maximum lifespan and perform with optimum efficiency if you make regular inspections and carry out some simple maintenance. Improvements in ventila- tion that lower the temperature in and around the unit are undoubtedly bene- ficial, while cleaning away build ups of dust and moisture on components such as circuit boards will help prevent failures and improve uptime. Monitoring and maintenance sched- ules that assess temperature, vibration and electrical supply can offer a further level of protection at the operator’s convenience, analysing the efficiency of drives while they continue to operate and offering consistent feedback data without interrupting production output. For users who operate a large number of drives on-site, Eriks offers a drives management programme, which begins with a survey of the specifica- tion, age and working conditions of each drive. A detailed analysis is then carried out, including a thermographic survey to check for tell-tale ‘hot’ connections and faulty thermal man- agement components. As a result of this and further temperature and airflow calculations, basic ventilation faults can quickly be remedied.
The question of whether to repair or replace is clearly one that requires consideration, but also one that should be tackled positively, since both options offer their own particular advantages. However, it is clear that the beneficial effect of simple mainte- nance techniques can extend drive operating life of all units, either repaired or replaced.
Eriks T: 0121 508 6219
www.eriks.co.uk
Enter 307 JULY/AUGUST 2011 Factory Equipment
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