When evaluating welding machines before purchase, metal fabricators usually consider factors such as upfront costs, welding process and output etc. Few consider how much it will cost to operate the machine over its lifetime. Here, we discuss two factors that you should consider, Power Efficiency and Power Factor.
What is Power Efficiency of Welding Machines?
Power efficiency relates to how efficiently a welding machine converts input power into welding power. A less efficient machine will drive up the costs of your utility bill. For the same welding parameters, an efficient machine may require 17kW of input power, while a less efficient machine may need 21kW. By choosing the less efficient machine, you are paying the utility company for 4kW of wasted power. Multiply this by the number of arc-on hours in a year, the number of machines in your fleet and the electricity costs ($/kWh), the amount of wasted power and money is significant.
What is Power Factor of Welding Machines?
Power factor refers to how efficiently a welding machine draws upon the energy provided by the utility. Power factor can be calculated by dividing Working Power (kW) by Apparent Power (kVA). A power factor of 1.0 is “perfect”.
Selecting welding machines with a low power factor comes with the following disadvantages:
- You may have to upgrade your existing electrical system in the current facility before adding new machines with low power factor. This is to prevent nuisance trips that can cause inconvenience and loss of productivity.
- If you are building a new facility, the construction costs for the new electrical system will cost you thousands of dollars more if you choose to use welding machines with low power factor. This is because the cabling, circuit breakers and other electrical components must be sized to match the higher current to be carried.
- Your utility company may charge you a penalty, on top of your existing utility cost, for using equipment with a low power factor.
Make an Informed Decision
Besides considering the upfront costs of the welding machine, it is also important to understand the total costs of operating the welding machine over its lifetime. We recommend Miller® welding machines for lower power consumption and operating costs. If you would like to have a discussion, reach out to us at SGOffice@MillerWelds.com