Digital overcurrent relay with voltage protection and 3×3-digit LED display TRM-30F

Overcurrent monitoring relay TRM-30F with display, 3-phase up to 25A

It serves to protect devices that are sensitive to operating current and voltage levels from faults caused by:

• Current overload (adjustable current value 0.5 ... 30 A)
• Current imbalance (50%, fixed value)
• Voltage imbalance (30%, fixed value)
• Overvoltage and undervoltage (Umin: 265 V, Umax: 440 V, fixed value)

The TRM-30F digital overload relay with display allows you to monitor the current in each phase and protect the motor or device from overcurrent, overvoltage, undercurrent, phase failure, and phase reversal. These digital overload relays are designed to prevent damage to the motor/load from high currents while simultaneously allowing you to monitor the current in each phase on the display. They are also capable of checking the cumulative voltage values ​​between the phases.

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

Application and Functionality

1. Connect the device according to the connection diagram. Incorrect connections can damage the device.
2. Adjust the device's overcurrent using the control ">A" according to the operating current of the load being tested.
3. When the device is switched on, the set overcurrent value appears in the upper display and the fault waiting time in the middle display within the first second.
4. After one second, the actual values ​​of the phase currents are displayed and the indicator LED lights up.
5. When the "V/A/RESET" button is pressed, the values ​​of the combined voltage between the phases are displayed.

driver

• "A>" - Setting the permissible overload; the value is displayed on the upper display.
• "Second." - Setting the waiting time in case of an overcurrent fault; the value is displayed on the middle display.

State of contact

• NO 95-96, NC 97-98:

• Device without power or in fault condition: NO open, NC closed.
• Device powered on and without faults: NO open, NC open.

LED display

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

Function of the "V/A/RESET" button

• Reset: Pressing for 3 seconds clears the error, the LED "A" goes out, the normally closed contact switches on, the normally open 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):

• Fault state activation: If the set overcurrent is exceeded, the set time is waited. Phase indicator flashes, LED "A" illuminates, NO open, NC closed, LED NOR off.
• To exit the fault state: If the current is below the setpoint, press Reset for 3 seconds.

2. Protection against current imbalance:

• Input: Current difference between phases >50%, wait 3 seconds, display flashes, LED "A" lights up.
• Exit: Difference <50%, press reset for 3 seconds.

3. Overvoltage protection (U>440 V):

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

4. Undervoltage protection (U<265 V):

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

5. Protection against voltage asymmetry:

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

6. Phase sequence protection:

• If the phase connection is incorrect, the LED "XI" lights up.

Calculation of current asymmetry

The device calculates the asymmetry using the following formula:

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

Technical data

• Supply voltage: measured voltage 3f 3x400 VAC
• Operating voltage (Un): 3x380 VAC 50/60 Hz, Power consumption <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 (LL)
• Undervoltage: 265 V (LL)
• Stress 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