Ingress Protection (IP) ratings are given to a variety of industrial devices like electrical enclosures and servo motors. IP is also referred to as the International Protection Rating. The IP rating system has value in both protecting workers and protecting equipment. The National Electrical Manufacturing Association (NEMA) provides a competing rating system but is used mainly in the United States. This brief article will provide a basic understanding of the IP rating methodology.
Most IP ratings are made up of two digits. The first digit is for solid particle protection and provides an indication of the degree of protection from access to hazardous parts (i.e., electrical conductors and moving parts). This number will tell whether a human hand or finger or other solid object like dust can enter the device. This digit ranges from 0 (no protection) to 6 (dust tight). A rating of 2 means that a device is finger-safe, such that fingers cannot get into the hazardous parts of the device.
The second digit is for ingress protection of liquids. This digit ranges from 0 (no protection) to 9 (powerful high temperature water jets). A rating of 4 means that water splashing from any direction will not enter the device. The highest IP rating value is 69.
Sometimes a letter is added (for example, f is oil resistance) and sometimes another digit is added to describe the devices resistance to mechanical impact. The mechanical impact energy rating goes from 1 (.225 joules) to 9 (20 joules).
New Motor Regulations on the Horizon
Machine Design Magazine has recently reported that new motor regulations are on the horizon. The United States Department of Energy has received a petition from a group of motor manufacturers to expand the recently adopted NEMA motor efficiency standards. While they asked not to increase the efficiency, they have asked to expand it to other motors and to close some loop holes. For example, a motor can be provided with a special shaft dimension and be exempt from the efficiency standards. Also, it is expected there will be first-ever rules for small single-phase motors. These motors will now require a start and run capacitor, increasing the size and cost of single-phase motors. These changes are expected to be required beginning in 2015.