# IRS Discharge Unit SSR – Semiconductor-based discharge unit up to 1500 V

Category: Hardware · Product page: https://irs.systems/en/products/hardware/discharge-unit-ssr

Two-channel, semiconductor-based discharge unit for DC links up to 1500 V: fail-safe, wear-free, with status signal and interlock contacts, for DIN rail mounting.

The IRS Discharge Unit SSR is a wear-free alternative to conventional discharge relays. It was designed for discharging capacitive DC links up to 1500 V DC. Thanks to solid-state relays, there is no contact wear even with short current peaks.

## Technical description

To discharge a capacitive DC link, the IRS Discharge Unit SSR switches a connected discharge resistor onto the DC load.

The control input is active low. If a line breaks or the control signal or the supply voltage fails, the unit therefore discharges automatically.

The potential-free interlock contacts can be wired into a safety controller, for example to switch off the power supply automatically while a discharge is active. The status feedback shows that discharge current is actually flowing – and thus that the discharge resistor is intact. It is designed for a 100 Ω resistor, so that the status signal responds from a voltage of 60 V.

The two channels are galvanically isolated from each other and from the 24 V control side. They can discharge either two separate DC links or one DC link redundantly together.

The basic function needs only the 24 V supply and the control signal. Status signal and interlock contacts are optional and can be used depending on the application.

## Technical data

| Parameter | Value |
| --- | --- |
| Discharge voltage | max. 1500 V DC |
| Channels | 2, galvanically isolated, single or redundant use |
| Discharge current | 15 A (at 100 Ω and 1500 V) |
| Max. DC link capacitance | 10 mF (at 100 Ω) |
| Supply | 24 V DC, approx. 1 W |
| Mounting | DIN rail TS35 (EN 60715) |

## Applications

**Test benches and test systems** Safe discharge of DC links in high-voltage test benches, for example for inverters and power electronics.

**Redundant discharge** Both channels on one DC link, each with its own discharge resistor.

**Two DC links** Each channel discharges its own DC link.

The IRS Discharge Unit SSR is available on its own or as a set with matching discharge resistors and the IRS Vol-Tran residual voltage monitor.

## List prices per unit

- Discharge Unit SSR: €500

Quotes and project inquiries: https://irs.systems/en/contact

## Documentation and downloads

- [Download datasheet German](https://file.irs.systems/08c18d94-2879-4ec0-87d7-40a398e0f965/Datenblatt_Discharge_Unit_SSR_DE.pdf)
- [Download datasheet English](https://file.irs.systems/f7336327-2dd5-4dce-aca2-bcebd326149e/Datenblatt_Discharge_Unit_SSR_EN.pdf)