Digital overcurrent relay with overvoltage protection TRM-30M

Current and voltage monitoring relay TRM-30M with display, 1-phase up to 30 A

Single-phase digital relay designed to protect sensitive equipment from overcurrent, overvoltage and undervoltage. It allows precise setting of current limit and time delay, and displays measured voltage and current values on a two-line display.

The TRM-30M is designed to protect 1-phase equipment sensitive to operating current and voltage values. The relay includes a current transformer in the package and has the following functions:

• overcurrent protection (adjustable current value 0.5 ... 30 A).
• overvoltage protection, voltage over 250 VAC (fixed value).
• undervoltage protection, voltage below 150 VAC (fixed value).
• Voltage hysteresis: 5 V (fixed value)
• Voltage error delay: 2 s (fixed value)
• Voltage error reset: 2 s (fixed value)

Operation and working principle

Connect the device according to the enclosed electrical diagram. Incorrect connection may damage the device. Set the overcurrent value according to the operating current values of the equipment used.

After connecting the power supply:

• The set overcurrent value appears on the upper display during the first second.
• The lower display shows the error delay time.
• The upper display shows the voltage between phase L and neutral conductor N.
• The lower display shows the current drawn from the mains after one second.

Settings

• A> - setting the overcurrent value; the value is displayed on the upper display.
• sec. - setting the waiting time before entering the overcurrent fault condition; the value is displayed on the lower display.

When power is connected, the NO contact is closed and the "OUT" indicator is lit.

If the device goes into an error condition:

• The corresponding indicator flashes
• The "OUT" LED turns off.
• NO contact opens
• NC contact closes

Protection functions

1. Overcurrent protection - entering a fault condition:

• If the current drawn from the mains exceeds the set overcurrent value, the device waits for the set delay time and then goes into error state.
• Fault condition: NO contact open, lower display flashes, "OUT" LED off, NC contact closed.

Exiting the fault condition:

• If the current drops below the set value, the device exits the error state after pressing the reset button for 3 seconds.
• Normal operation: NO contact closed, lower display steady, "OUT" LED on, NC contact open.

2. Overvoltage protection (U > 250 V) - input:

• If the voltage is above 250 V, the device waits for 2 seconds and enters the fault condition.
• Fault condition: NO contact open, upper display flashes, "OUT" LED off, NC contact closed.

Output:

• The device automatically exits the fault condition 2 seconds after the voltage drops below 245 V.
• Normal operation: NO closed, upper display steady, "OUT" LED on, NC contact open.

3. Undervoltage protection (U < 150 V) - input:

• If the voltage is below 150 V, the device waits for 2 seconds and enters the fault condition.
• Fault condition: NO open, upper display flashes, "OUT" LED off, NC contact closed.

Output:

• Automatic termination of the fault condition 2 seconds after the voltage rises above 155 V.
• Normal operation: NO closed, upper display steady, "OUT" LED on, NC open.

Error signal

• Top display flashes: in case of high or low voltage error.
• Bottom display flashes: in case of overcurrent.
• LED OUT: lights up when the device is in normal condition. NO contact closed.

Device status