When we talk about the Electrification of Everything, we have in mind not least the paradigm shift in driving. And, along with that, in charging. In future, the latter won’t be possible with the public charging station infrastructure alone. Affordable and clever domestic wall box solutions for the garage and carport are utterly required - and so are components like HE-R relays, that meet the specific needs of next-gen 3 phase systems.
Let's start with a look back at more recent encounters with high loads: Whenever it came to the task of handling them, application engineers suffered some headache in terms of relays. High power environments usually required the use of rather large, stand-alone contactors that had to be mounted as separate units with wired connections to a control board.
In the end, this resulted in higher component and material costs, additional manual assembly efforts and sometimes even the risk of poor operational reliability, because every single connection from the board to the cables and the socket to the relay connection can turn out to cause reliability issues.
HE: A new generation of PCB based power relays
To overcome these shortcomings and to serve the growing demands for safe, robust and energy-efficient ways to switch relatively large amounts of power on the PCB, Panasonic Industry introduced its HE relay series nearly 20 years ago, at this time with a focus on the solar energy plants market.
The lineup grew over the years, and now in 2022 HE relays can handle loads up to 120A (HE-N) and up to 1000VDC
(HE-V) in ambient temperatures of up to 85°C. This makes the PCB relay series a perfect choice for high power applications, such as solar inverters, automotive charging stations, or battery storage systems – while coming in remarkably compact dimensions. HE-S, for instance is as compact as 30x36x40mm.
HE-R: The small box for the wall box
The latest member of the HE relays family, the HE-R 4a and HE-R 2a can be used as the main switching element in three-phase (HE-R 4a) systems and single-phase systems (HE-R 2a and 2a1b).
Designed specifically for mode 3 AC charging stations up to 22kW, the HE-R is meant to take charging technology safety to the next level: Each of the four normally open contacts is designed for carrying and switching 40A within the series’ usual temperature range of up to +85°C. An optional NC contact, designed as a mirror contact according to IEC 60947-4-1, switches signal loads up to 10mA / 5VDC.
In addition to the HE-R’s small size of 35 x 58 x 47mm (4a version) and 37 x 60 x 47mm (2a version), its minimal power consumption would be a key feature. This could be achieved by using a pulse width modulation to reduce the coil voltage to only 35% of the nominal voltage. This results in a remarkably low power dissipation of only 490mW. Positive side effect: A lower waste heat renders ventilation redundant in most of the cases and the relays heat dissipation is low.
Size, performance, and robustness
Both HE-R Relays, the 4a or 4a1b and 2a or 2a1b version comply the required short circuit capability:
- 2 Form A/2 Form A 1 Form B: Irms ＝ 5 kA ( Compliant with UL508 )
- 4 Form A/4 Form A 1 Form B: Ip ＝ 2.6 kA, I2t ＝ 6.5 kA2s (Compliant with IEC62955)
This is not only an option for demanding garage and carport wall box designs, but also for public charging stations and completely different application areas such as industrial automation or energy harvesting.
- Unique contact arrangement of 4a or 4a1b and 2a 2a1b
- 1xNC contact as a mirror contact
- Contact rating 4pole version: 40A / 480VAC resistive
- Contact rating 2pole version: 70A / 277VAC resistive
- Extreme low coil holding power of 490mW
- Clearance & creepage distance >8.0 mm
- Ambient temperature - 40°C to +85°C
- PCB soldering terminal type
- UL/C-UL, VDE certified
 |
 |
 |
|
|---|---|---|---|
| Series | HE-S | HE-R | |
| Switching current AC | 35A | 40A/80A | |
| Contact arrangement | 2FormA, 2FormA 1FormB | 4FormA, 4FormA 1FormB/ 2FormA, 2FormA 1FormB | |
| Max. switching voltage | 480VAC | 480VAC/ 277VAC | |
| Contact gap | 3.2mm | 3.6mm | |
| Holding power | 170mW | 490mW | |
| Dimensions | 30 x 36 x 40mm | 35 x 58 x 47mm/ 37 x 60 x 47mm |
|
Download HE-S datasheet Download HE-R datasheet