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

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

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

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

Device usage and operating principle

1. Connect the device according to the wiring diagram.
2. When wiring is complete, connect the power supply. Upon power-up, the set values are displayed on the screen for 5 seconds.
3. Use the "A>" controller to set the overcurrent value. The set value is displayed on the left screen.
4. Use the "t" controller to set the delay time. The set value is also displayed on the left screen.

When the device is turned 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 down 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 turns off.

The TRM-300 series electronic current relay is designed for automatic disconnection of devices when the maximum allowable current is exceeded.
It has a programmable cutoff range, with options to set cutoff time and return time.
There are 3 programs available to return to "operational" mode - MANUAL, SEMI-AUTOMATIC, AUTOMATIC.

Reset modes:

- Manual mode: After a fault caused by overcurrent, the device must be reset by pressing the Reset button. In this mode, the corresponding LED diode lights up.
- Semi-automatic mode: The system automatically resets itself three times after a fault caused by excessive current; on the next fault, it waits for a manual reset. In this mode, the LED indicator lights up.
- Automatic mode: The system automatically resets after each overcurrent fault. In this mode, the LED indicator is lit.

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 asymmetric fault mode within 2 seconds.
(This prevents system damage in case of failure of one phase during motor operation).

During asymmetric fault:
- The display group of both phases that caused the fault flashes, and the ERR indicator lights.
- To exit asymmetric fault mode, the device must be manually reset.

Technical parameters:

- Operating voltage: 150-260 VAC.
- Operating frequency: 50/60 Hz
- Power consumption: < 6 VA
- Operating temperature: from -20 °C to +55 °C
- Display: 3 × 3 digits, 5 LEDs
- Overcurrent setting (A>): 190-300 A
- Delay time: 1-200 s
- Connection type: clamp 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: Models TRM-50, TRM-100, TRM-200, and TRM-300 can only be used with current transformers supplied with the device.

Basic