TRM-30F Three-Phase Overcurrent and Voltage Protection Digital Relay with 3x3 Digit LED Display

Overcurrent monitoring relay TRM-30F with display, three-phase up to 25A

It is designed to protect equipment sensitive to operating current and voltage values from faults that may occur due to:

• current overload (adjustable current value 0.5 ... 30 A)
• current asymmetry (50%, fixed value)
• voltage asymmetry (30%, fixed value)
• overvoltage and undervoltage (Umin: 265 V, Umax: 440 V, fixed value)

The digital overcurrent overload relay TRM-30F with display allows you to view the current in each phase and protect the motor or appliance against overcurrent, overvoltage, undercurrent, phase failure, and phase reversal. These digital overload relays are designed to prevent damage to the motor or load from high currents, while allowing you to monitor the current flowing in each phase on the display. They are also able to check the accumulated voltage values between phases.

With two output relays (1x NO, 1x NC), it is also possible to control or disconnect the load when the overcurrent reaches a set value, or activate a signaling contact to the control system. TRM-xx digital relays incorporate current transformers and a 3x3 digit display for current visualization.

Application and operating principle

1. Connect the device according to the wiring diagram. Incorrect connections can damage the device.
2. Adjust the device's overcurrent using the ">A" knob according to the operating current of the load being controlled.
3. When power is connected, in the first second, the adjusted overcurrent value will appear on the top display, and the fault waiting time on the central display.
4. The actual current values of the phases will appear after one second of operation, and the indication LED will light up.
5. When the "V/A/RESET" button is pressed, the combined voltage values between the phases are displayed.

Controllers

• "A> " - admissible overload setting; the value is displayed on the top screen.
• "sec." - overcurrent fault waiting time setting; the value is displayed on the central screen.

Contact Status

• NO 95-96, NC 97-98:

• Device unpowered or in fault: NO open, NC closed.
• Device energized and no fault: NO open, NC open.

Indication LEDs

• "V" LED - lights up in case of overvoltage/undervoltage fault or voltage asymmetry.
• "A" LED - lights up in case of high current or current asymmetry fault.
• "XI" LED - lights up when the phase sequence is incorrect.
• "NOR" LED - lights up when the device is powered and the system is fault-free.

"V/A/RESET" button function

• Reset: a 3-second press clears the fault, the "A" LED turns off, the NO contact turns on, the NC contact opens.
• V/A: a short press switches the display between current and voltage values.

Protection and operating principle

1. Overcurrent protection (0.5-30 A):

• Entering fault state: when the set overcurrent is exceeded, the set time is waited. The phase indication flashes, the "A" LED is on, NO open, NC closed, NOR LED off.
• Exiting fault state: current below setpoint, press reset for 3 seconds.

2. Current asymmetry protection:

• Entry: current difference between phases >50%, wait 3 seconds, display flashes, "A" LED on.
• Output: difference <50%, press reset for 3 seconds.

3. Overvoltage protection (U>440 V):

• Input: voltage >440 V, wait 3 seconds, display flashes, "V" LED lights up.
• Output: voltage <435 V for 3 seconds.

4. Undervoltage protection (U<265 V):

• Input: voltage <265 V, wait 3 seconds, display flashes, "V" LED lights up.
• Output: voltage >270 V for 3 seconds.

5. Voltage asymmetry protection:

• Input: voltage difference >30%, wait 3 seconds, display flashes, "V" LED lights up.
• Output: difference <30% for 3 seconds.

6. Phase sequence protection:

• An incorrect phase connection will light up the "XI" LED.

Calculation of current asymmetry

The device calculates asymmetry using the formula:

Example: ((25 - 15) / 25) × 100 = 40% current asymmetry.

Technical specifications

• Power supply voltage: measured voltage 3ph 3x400 VAC
• Operating voltage (Un): 3x380 VAC 50/60 Hz, own power <10 VA
• Adjustable overcurrent (overload): 0.5-30 A
• Fault waiting time (t): 0-20 s
• Display: 3x3 digits, 9 mm height, 7 indicator LEDs
• Overvoltage: 440 V (L-L)
• Undervoltage: 265 V (L-L)
• Voltage asymmetry: 30%.
• Current asymmetry: 50%.
• Waiting time for asymmetry error: 3 s
• 2x output relays (1x NO, 1x NC): 3 A / 250 V AC (resistive load)
• Connection type: screw terminals
• Cable cross-section: 2.5 mm² (relay contacts) / 6 mm² (input and output loads for measurement)
• Weight: max. 380 g
• Mounting: on DIN rail
• Operating temperature: -20°C ... +55°C
• Operating altitude: <2000 m