High Voltage Relays

Switch high voltages and high currents without problem – with the relays by SPS electronic

For voltages going up to 10,000 V and currents up to 30 A, high voltage relays from SPS electronic are used in many technical devices. Originally, the relays have been used only in the test equipment and test systems of SPS electronic. However, it has quickly shown that a global market exists for these special parts.

Different variants are derived from the basic type RL 42 with double pole double throw contacts. Also, high-voltage relays with single pole double throw contact (RL 21) or for higher voltages (RL 42-h and RL 38-h) are available. If many relays are required in a device the excitation current is an important parameter. Therefore you will find in our range a high-voltage relay for much lower excitation current. The relay RL 42-l has a power electronics that reduces the energising circuit to the holding current. The result is power consumption which is lower by a factor of 3. Since the low current also reduces the power, the winding of the relay is less thermally stressed. This benefits not only the relay, but also the entire system. Since, the heat must be dissipated again.

Are there alternatives to electromechanical high voltage relays?

In technology, an electro-mechanical relay cannot be completely replaced by an electronic switch. The main argument is the electrical isolation of the lines that are to be opened. That is not a given for electrical switches. A further, essential point is the safe isolation of lines. Contingent on the electro-mechanical concept, it can be ensured that the relay is not switched without excitation voltage. In the case of electronic switches such as transistors or thyristors, the component can be defective through an overload and cause a short-circuit. That is an absolute no-go for safety-relevant switching circuits.

Even Reed relays are not a good alternative. This technical concept may be cheaper but cannot replace an electro-mechanical relay. Through the setup of the Reed relay, the Reed contact has to open “on its own”. This has the consequence that Reed relays are often left “hanging” and cannot be opened, which is prohibitive for many applications. Due to the functional principle of the Reed relay, these switches can only switch low currents. That significantly limits the applications. So Reed relays are no alternative for a lot of applications.

Last but not least, vacuum relays are offered on the market. This technology builds on the principle that merely little gaps are needed in an airless space for the isolation. Noble gases are often used too. Due to the gas-tight glass containers, the relays are quite expensive and are only available for low currents. So also not an alternative to the electro-mechanical relays by SPS electronic.