This document introduces the technical parameters and functional principles of MSCR301B/302B voltage relays. The relay has the advantages of adjustable action value and return coefficient, as well as stable contact performance. It can be used as an action element for overvoltage or undervoltage lockout in the relay protection devices of generators, transformers, and transmission lines.
The MSCR301B/302B voltage relay is designed for use in generator, transformer and transmission line protection circuits, acting as an over‑voltage or under‑voltage trip element. It features an integrated‑circuit design with easy‑adjustable set points, digital rotary switches, and clear action indicators. The relay is mounted on a standard parallel rail for convenient installation and wiring.
The device supports three voltage levels (100 V, 200 V, 400 V) with adjustable ranges of 0.000‑0.999 Ue and a fine step of 0.001 Ue. It operates from an auxiliary supply of 100‑370 VDC or 85‑265 VAC, consumes no more than 6 W at 220 VDC, and has a maximum contact current rating of 5 A with a breaking capacity of 60 W (DC 220 V). The action time does not exceed 40 ms. Physical dimensions are shown in the mounting drawing (width 103.5 mm). This manual is written in Chinese.
| Auxiliary power rating | 100‑370 VDC / 85‑265 VAC |
|---|---|
| Rated voltage | Ue=100 V, 200 V |
| Rated frequency | 50 Hz |
| Contact type | 2 normally open, 2 normally closed |
| Adjustment range | 0.000‑0.999 Ue |
| Maximum power consumption (200 V AC) | ≤0.5 VA |
| Voltage accuracy | ≤ +2 % |
| Operating power (220 VDC) | ≤ 6 W |
| Action time | ≤ 40 ms |
| Contact current rating | 5 A |
| Contact breaking capacity | 60 W (DC 220 V) |
| Supported voltage levels | 100 V, 200 V, 400 V |
| Mounting width | 103.5 mm |
It is used in generator, transformer and transmission line protection as an over‑voltage or under‑voltage trip element.
The relay can be powered from an auxiliary supply of 100‑370 VDC or 85‑265 VAC.
The contacts are rated for a continuous current of 5 A and a breaking capacity of 60 W at 220 V DC.
The action time is no more than 40 ms.