IEC standards now recommend that surge protective devices be installed at the supply point of the facility. The publication of the installation standards IEC 60364-4-44 and IEC 60364-5-53 in September 2015 motivated the use of surge protective devices (SPDs). This requirement is no longer just valid for commercial and industrial facilities, but also applies to […]
Which is more cost-effective in reducing energy consumption and providing the most satisfactory payback time in pump applications, frequency converters or soft starter technologies? In water applications, centrifugal pumps are driven by induction motors fed directly from the network. Flow regulation is accomplished by a few different means, namely throttling, a highly inefficient method as […]
With an estimated 2-billion units installed, small motors (<750 W) are reported to account for 90% of the global electric motor population [1]. Small electric motors of up to 1 kW output are central to a large number of applications and are installed as drive elements in many types of end-user and industrial equipment. Permanent […]
A closer look at soft starters and VFDs, their advantages, disadvantages and applications. A large starting current may be required (typically 5 – 7 x FLC) when accelerating an AC motor to full speed using a full voltage connection. Additionally, the torque of the AC motor is mostly uncontrolled and can shock the connected equipment, […]
This article considers the technologies and topologies of MV drives, their advantages disadvantages and their impact on the quality of energy on the mains and motor sides. Advancements in semiconductor devices such as insulated gate bipolar transistors (IGBTs) allow medium voltage (MV) drives to be used increasingly to conserve energy, increase productivity and improve product […]
Motor manufacturers are reporting an increase in damage to bearings and connected equipment caused by electrical current flow. The failure rate of bearings and connected equipment due to current flow is thought to be small relative to the total number of motors sold, but the frequency of failures is growing as more users install pulse-width […]
Equipment damage, arc flash hazards and unplanned outages are greatly reduced when overcurrent protection devices are operated and maintained properly. Business owners and facility management teams are increasingly concerned with their ability to keep their equipment working at peak performances. This leaves them with the task of managing the myriad maintenance challenges which include extending […]
Why transformer-free uninterrupted power supplies (UPSs) meet the vast majority of power supply design requirements. The first double-conversion UPSs where born in the 1970s. The semiconductors available at the time were bigger and less compatible with voltage levels than they are today. As a consequence, UPS systems needed transformers to step up the voltage of […]
The miniature circuit breaker (MCB) has replaced the fuse in incoming distribution boards since the 1960s, so increasing incoming protection by making it impossible to bypass blown fuses with nails or wire – a frequent and dangerous practice. Functioning of the MCB An MCB is a mechanical switching device able to make, carry and break […]
This article discusses a break-through in the field of electrical protection and identifies critical application areas where arc fault detection devices enhance safety. Although the terms, “arc fault” and “arc flash” look and sound similar, they are very different and are often confused. Electric arc faults occur when an electric arc current is generated in […]
