Types of Power Relays: Miniature, PCB, and Industrial Relays

Power relays are categorized by mechanical features – miniature, PCB, industrial, and more. While miniature power relays are small this term does not always indicate absolute size, PCB power relays are designed to be mounted onto printed circuit boards (PCBs). Industrial relays are typically used in switching cabinets by control panel builders. Industrial relays are engineered to meet industry expectations such as Underwriters Laboratory (UL).

The basic design of electromechanical power relays is the same, regardless of whether it is a miniature PCB relay or an industrial power relay. Power relays have three subsystems: contact system, magnetic system, and mechanical components. The primary components in a power relay include – on the contact system, or secondary side – fixed contacts, moving contacts (moved by the magnetic system – the motor – to switch the load circuit), and contact springs (holding the contacts but flexible enough to all the contacts to move).

The magnetic system includes the coil (generates the necessary magnetic field to actuate the armature and contacts), the core, the yoke (establishes the magnetic circuit), the armature (the moving part that closes and opens the magnetic circuit and acts – via a comb or actuator – on the moving relay contacts), and the return spring (establishes the defined position of the magnetic and contact system in case the coil is not energized).

The mechanical components include the case, base, insulation (separates the primary circuit from the secondary side and provides required insulation), actuator (can translate motion of magnetic system to the moving contacts), pins or terminals (connects the contact system and the load), and mounting devices. Most power relays are monostable (non-latching) relays with a neutral coil system and only one stable position. These will stay in this non-energize state, without receiving power. 

TE Connectivity (TE)’s ECP40B series high-voltage DC contractor is designed for control in high voltage environments like battery energy storage system, solar inverters, and EV charging applications. ECP40B series is designed and suited for pre-charge applications. It can be used in 1500 VDC voltage systems, and the enhanced insulation distance meets the requirement of UL60947-4-1 and IEC60947-4-1 standards. The contacts provided in this series allows bi-directional load and are hermetically sealed with ceramic sealing technology, making it safer and more reliable. 

TE Connectivity (TE) introduces the T9F series 32Amp miniature relays designed for generating control in the latest energy and power supply applications. The T9F series product line is a noteworthy and reliable solution for EV charging, power supply, solar inverters, and battery energy storage system applications. It has 32Amp current capability and is suitable for 105⁰C environments. More importantly, its size is significantly minimized to create space savings for the customer.

TE Connectivity (TE)’s SCHRACK SR4 is a compact and space efficient force guided relay for loads up to 8 A. The optimized ratio between 13 mm width and 16.5 mm height helps allow miniaturization for horizontally or vertically installed PCBs and modules. With its force guided contact set, the state of a contact can be monitored with a diagnostic coverage of 99% (IEC 61508-2) which makes the SR4 highly reliable to design safety circuits. The SR4 is produced both in Europe and China to optimally serve local customers.

The ECP600B series high-voltage DC contactor which is designed for control in high-voltage environments in battery energy storage systems, solar inverters, and EV charging applications. The special contact design enables it to endure bi-directional load and perform well under a 1500VDC voltage system with a long life and high reliability.

TE Connectivity (TE) introduces the ECK 150B, 200B & 250B high-voltage DC contactor series, designed for control in new energy applications. The ECK product line is an innovative and reliable solution for EV charging stations, solar inverters, battery energy storage systems, automated-guided vehicles (AGVs) & e-Forklifts and other high voltage applications. They allow bi-directional loads and are hermetically sealed with ceramic sealing technology making it safe and reliable. These contactors can be used in 1000VDC system applications.

TE Connectivity (TE) introduces the ECK 50B/100B high-voltage DC contactor series which is designed for control in new energy applications. The ECK product line is an innovative and reliable solution for EV charging stations, solar inverters, battery energy storage systems, automated-guided vehicles (AGV), and e-forklifts. These contactors allow bi-directional loads and are hermetically sealed with ceramic sealing technology making them safe and reliable. They are also suitable for 1000VDC system applications.