Digital overcurrent relay with 3×3-digit LED display TRM-300

Three-phase relay for load current control/limitation in the range of 190-300 A, manufacturer TENSE (Turkey)

The TRM-300 digital overcurrent relays are designed to protect loads from damage caused by high currents while enabling operational monitoring.

- 190-300 A (adjustable overcurrent value)
- 50% fixed current asymmetry
- adjustable fault delay time
- adjustable operating mode (automatic, semi-automatic, manual)
- When purchasing a TENSE brand current relay, you receive a ready-to-use device - current transformer included.

Usage and operating principle

1. Connect the device according to the wiring diagram.
2. When wiring is complete, turn on the device. After turning on, the display shows the set values for 5 seconds.
3. Use the "A>" dial to set the overcurrent value. The set value is shown on the left display.
4. Use the "t" dial to set the delay time. The set value is also displayed on the left display.

When turning on the device:
- The relay pulls in, the output contact switches to terminal 3, and the OUT indicator lights up.
- When the current exceeds the set overcurrent value (A>), the device starts the countdown of the delay time and the ERR indicator lights up.
- After the time expires, the relay switches off, the contact switches to terminal 1, and the OUT indicator goes off.

The TRM-300 series electronic current relay is used for automatic shutdown of devices when the maximum allowable current is exceeded.
It features a programmable trip range, the ability to set the trip time and reset time.
There are 3 programs to return to "operating mode" - MANUAL, SEMI-AUTOMATIC, AUTOMATIC.

Reset modes:

- Manual mode: After an overcurrent fault, the device must be reset by pressing the reset button. In this mode, the corresponding LED lights up.
- Semi-automatic mode: The system automatically resets three times after an overcurrent fault and then waits for a manual reset at the next fault. In this mode, the LED indicator lights up.
- Automatic mode: The system resets automatically after each overcurrent error. In this mode, the LED indicator lights up.

Note: To change the mode, hold the SELECT button for 10 seconds. When the mode changes, the corresponding LED lights up.

Asymmetry 50% (fixed)

If the difference between the highest and lowest phase current exceeds 50%, the device enters asymmetry error mode within 2 seconds.
(This prevents system damage in case of a single-phase failure during motor operation).

During an asymmetry error:
- The display group of the two phases that caused the error blinks and the ERR indicator lights up.
- To exit the asymmetry error mode, the device must be reset manually.

Technical parameters:

- Operating voltage: 150-260 VAC.
- Operating frequency: 50/60 Hz
- Power consumption: < 6 VA
- Operating temperature: -20 °C to +55 °C
- Display: 3×3 digits, 5 LEDs
- Overcurrent setting (A>): 190-300 A
- Delay time: 1-200 s
- Connection type: terminal connection
- Contacts: 5 A / 250 V AC (active load)
- Wire diameter: 2.5 mm²
- Weight: max. 250 g
- Mounting: on DIN rail
- Operating altitude: < 2000 m

Note: The TRM-50, TRM-100, TRM-200, and TRM-300 models can only be used with the supplied current transformers.

Basics