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

TRM-30F Overvoltage Monitoring Relay with Display, 3-phase, up to 25 A

It is designed to protect equipment sensitive to operating current and voltage values from errors 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 current overload relay TRM-30F with display allows viewing the current of each phase and protects the motor or device from overcurrent, overvoltage, undercurrent, phase failure, and phase sequence change. These digital overload relays are designed to protect the motor/load from high current damage, while allowing monitoring of the current flowing in each phase on the display. They can also check the total voltage values between phases.

Using 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 to activate a signal contact for the control system. The digital TRM-xx relays have built-in current transformers and a 3x3 digit display to show the current.

Application and Operating Principle

1. Connect the device according to the wiring diagram. Incorrect connection may damage the device.
2. Set the device's overcurrent using the ">A" controller according to the operating current of the load you will be checking.
3. When power is applied, the set overcurrent value will appear on the top display for the first second, and the fault delay time on the middle display.
4. Actual phase current values will be displayed after one second of operation, and the indicator LED will light up.
5. Pressing the "V/A/RESET" button displays the total phase voltage values.

Controls

• "A>" - setting of allowed overload; value is displayed on the upper screen.
• "sec." - setting of overcurrent fault delay time; value is displayed on the middle screen.

Contact Status

• NO 95-96, NC 97-98:

• Device unpowered or in fault state: NO open, NC closed.
• Device powered and fault-free: NO open, NC open.

Indication LED

• "V" LED - lights up for overvoltage/undervoltage or voltage asymmetry fault.
• "A" LED - lights up for overcurrent or current asymmetry fault.
• "XI" LED - lights up when the phase sequence is incorrect.
• "NOR" LED - lights up when the device is powered on and there are no system errors.

"V/A/RESET" button function

• Reset: press for 3 seconds to clear the fault, "A" LED turns off, NO contact closes, NC contact opens.
• V/A: short press to toggle between current and voltage values on the display.

Protection and Operating Principle

1. Overcurrent protection (0.5-30 A):

• Entering fault state: if the set overcurrent is exceeded, wait for the set time. The phase display flashes, the "A" LED lights up, NO opens, NC closes, NOR LED turns off.
• Exiting fault state: current is less than the set value, press Reset for 3 seconds.

2. Current asymmetry protection:

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

3. Overvoltage protection (U>440 V):

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

4. Undervoltage protection (U<265 V):

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

5. Voltage asymmetry protection:

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

6. Phase sequence protection:

• The "XI" LED lights up due to incorrect phase connection.

Current Asymmetry Calculation

The device calculates asymmetry using the formula:

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

Technical Specification

• Supply voltage: measured voltage 3f 3x400 VAC
• Operating voltage (Un): 3x380 VAC 50/60 Hz, self-power <10 VA
• Adjustable overcurrent (overload): 0.5-30 A
• Fault delay 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%
• Asymmetry fault delay time: 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 measurement loads)
• Weight: max. 380 g
• Mounting: on DIN rail
• Operating temperature: -20 °C ... +55 °C
• Operating altitude: <2000 m