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

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

Digital overcurrent relays TRM-300 are designed to protect loads from damage caused by high currents, while allowing 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 current relay of the TENSE brand, you get a ready-to-use device - current transformers included.

Device usage and operating principle

1. Connect the device according to the wiring diagram.
2. Once wiring is complete, connect the device to the mains. After powering on, the set values will be displayed on the screen for 5 seconds.
3. Use the "A>" knob to set the overcurrent value. The set value will be displayed on the left screen.
4. Use the "t" knob to set the delay time. The set value will also be displayed on the left screen.

When the device is powered on:
- The relay switches on, the output contact switches to terminal 3, and the OUT indicator lights up.
- If the current exceeds the set overcurrent value (A>), the device starts counting the delay time and the ERR indicator lights up.
- When the time has elapsed, the relay switches off, the contact switches to terminal 1, and the OUT indicator turns off.

The TRM-300 series electronic current relay is designed for automatic shutdown of equipment when the maximum permissible current is exceeded.
It features a programmable switching range, the ability to set switching time and return time.
There are 3 programs for the "Operating Mode" return: MANUAL, SEMI-AUTOMATIC, AUTOMATIC.

Return modes:

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

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

Asymmetry 50% (fixed)

If the difference between the largest and smallest phase currents exceeds 50%, the device enters asymmetry fault mode within 2 seconds.
(This prevents system damage in case of a single-phase fault during motor operation).

When an asymmetry fault occurs:
- The group of readings of the two phases that caused the fault will flash, and the ERR indicator will light up.
- To exit asymmetry fault mode, the device must be reset manually.

Technical parameters:

- Operating voltage: 150-260 V AC
- Operating frequency: 50/60 Hz
- Power: < 6 VA
- Operating temperature: -20 °C to +55 °C
- Display: 3×3 digits, 5 LED
- 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
- Installation: DIN rail
- Operating altitude: < 2000 m

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

Basic