Capital Equipment News August 2019

is electrical. You will never find a motor that operates at 100% efficiency because losses exist in all motors due to friction, heat generation and materials, to name a few factors. specific benchmark in large HV motors because they fall out of SABS standards – they are usually purpose-built, application-engineered motors. However, WEG’s machines are designed to the highest efficiency standards, which range from 90-96%. Spohr says HV motors are capital intensive pieces of equipment. They may cost anywhere between R2-million and R25-million. Because of the high capital cost, some operators of this gear tend to run their motors well beyond their design lifetime. Meanwhile, when it is replacement time, there is always a big focus on the capital cost at the expense of efficiency, which is a key factor in overall cost of ownership. When it comes to running old technology motors, Spohr reasons that it is always important to remember that every motor is designed with a specific economical lifetime. He reasons that today’s engineering is a lot more precise and motors are designed for 25-30 year operation with guaranteed efficiency within that period of time. “Due to the perceived large capital cost of these machines, some end users tend to run their HV motors for a much longer period than what they were designed for. Some of them even exceed by an additional 10- 15 years,” he says. According to Spohr, if one looks at a five to 10-year running cycle of a low voltage motor, for example, the capital cost of the machine equates to only 2% of the total cost of ownership during that time. This is because of the high energy consumption costs; motors by their very nature consume a lot of electricity, and for that reason, efficiency is a key priority. “For example, in low voltage motors, within a five-week period, the actual running cost – what the end user has paid in electricity consumption to run the motor – will come close or exceed the initial capital cost of a new motor,” says Spohr, adding that this may be slightly different when it comes to high voltage motors because the capital cost is significantly higher. “For instance, the capital cost of a 110 kW motor is about R66 000, and within five weeks, the motor would have consumed R71 000 worth of electricity. Over a five-year period, the end user When it comes to the efficiency benchmark, Spohr says there is no

While the spotlight is largely cast on the upfront capital cost, the fact of the matter is that purchase price is a very small factor in the overall cost of HV motor ownership

Efficiency and maintenance costs are two key factors of consideration in the overall cost of running an HV motor

Only 2% of the total lifecycle cost of an electric motor is attributable to the initial purchase price

Close to 97% of the total lifecycle cost of an electric motor represents the energy costs used to power the machine

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Efficiency matters According to Spohr, efficiency is a big factor in achieving lower TCO in motors. Firstly, it is important to understand what efficiency is. Motor efficiency is the ratio between power output, which is mechanical, and power input, which

purpose-engineered motors that are used in manufacturing facilities, beneficiation plants, mines and quarries. “Very few of the end users of this equipment think about TCO and probably even fewer actually understand what it costs to operate HV motors,” reasons Spohr.

CAPITAL EQUIPMENT NEWS AUGUST 2019 13