New Three-Phase, Dual-Stage EMI Filter Products From EMIS

Recently, EMIS announced a new line of EMC (electromagnetic compatibility) filters designed specifically for reducing electrical noise in situations with high levels of interference, most visible in noisy industrial environments around inductive motors and VFDs.

For over forty years, EMIS has been designing and producing electromagnetic compatibility filters for multiple industries on a global scale. With its headquarters in Sweden, EMIS offers products consisting of EMI/EMC components, harmonic filters, reactors, feedthrough capacitors, and surge protectors.

The new TMF dual-stage filter for 3-phase power. Image used courtesy of EMIS

EMC Filter In Automation

Within automation equipment we often use VFDs, motor controllers, or servo drives, these devices manipulate electrical frequency to control motion in the physical world. Sometimes the electrical frequency leaks back into the supply, creating a condition known as electromagnetic interference or EMI, affecting other devices and operations around the connected system. To reduce the effects of this EMI, a filter that is designed for compliance against the effects (known as an EMC filter), is used to reduce the fluctuations within the electrical supply.

An example of a standard single-phase input power line filter. Image used courtesy of EMIS

TMF Product Line

Designed with motor drives in mind, the TMF product line is compact and capable of being mounted next to inverters, converters, and motor drives commonly found in machinery and machine tools. Two models are provided, one offering industry-standard attenuation (TMF3221) and the other offering high attenuation (TMF3222) for applications with EMI-susceptible equipment.

A high-voltage option is provided for the TMF3222 (TMF3222HV), capable of a continuous maximum voltage of 760 VAC, all other models have a maximum rating of 530 VAC. The operating frequency for all the models is 50/60 Hz with an operating temperature range of -40°C to 100°C and is IEC and UL certified. The operating current ranges from 10 A to 230 A at 50°C. While the TMF3221 and the TMF3222 are designed specifically for motion controllers, they also offer a variant designed for IT solutions.

The TMF product line offers many versions of the TMF3221 and the TMF3222 with different current ratings, leakage current, and power losses. Four slotted holes provide mounting to backplanes within the control cabinet.

EMI In Automation

Many electronic devices can be sources of EMI within industrial equipment, most commonly VFDs and servo drives with AC motors sometimes also producing EMI. These devices are known to produce EMI so manufacturers will often recommend a properly sized filter be installed with the motion controller. Exercising proper cable management, such as separating AC and DC cables as well as separating AC and DC devices and keeping cable runs as short as possible will also help reduce excessive EMI within the equipment.

Control cabinets with VFDs can be both a source and a victim of EMI problems. Image used courtesy of Wikipedia

Protecting Sensitive Equipment

Some equipment is sensitive to electrical noise, such as analog I/O, vision light drivers, and laser markers. If the noise in the electrical supply fluctuates too much incorrect values could be measured from the analog inputs, lights might be triggered at high frequencies, and laser markers could fault causing machine downtime. Machine builders that are shipping equipment to the European market will need to pertain to CE requirements for EMI, which are much tighter than the IEC standards used in North America. It is important to measure your EMI and properly size and select an EMC filter to reduce electrical noise as much as possible.