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 caused by high currents while allowing operation monitoring.

- 190-300 A (adjustable overcurrent value)
- Fixed current asymmetry of 50%
- Adjustable error delay time
- Adjustable operating mode (automatic, semi-automatic, manual)
- When purchasing a TENSE brand current relay, 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, apply power. After power-on, the display shows the set values for 5 seconds.
3. Use the "A>" regulator to set the overcurrent value. The set value is displayed on the left display.
4. Use the "t" regulator to set the delay time. The set value is also displayed on the left display.

When the device is powered on:
- The relay activates, 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 expires, the relay turns off, the contact switches to terminal 1, and the OUT indicator turns off.

The TRM-300 series electronic current relay is designed to automatically disconnect devices when the maximum allowed current is exceeded.
It has a programmable intervention range, the ability to set the intervention time and the return time.
There are 3 programs to return to "operational" mode: MANUAL, SEMI-AUTOMATIC, AUTOMATIC.

Reset mode:

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

Note: to change mode, press and hold the SELECT button for 10 seconds. When changing mode, the corresponding LED indicator lights up.

Asymmetry 50% (fixed)

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

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

Technical parameters:

- Operating voltage: 150-260 V AC
- 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: 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: TRM-50, TRM-100, TRM-200, and TRM-300 models can only be used with the current transformers supplied with the device.

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