3 phase digital overload overcurrent relay / current monitoring relay / priority relay 0,1A – 25A

This current monitoring relay is designed by Tense Electronics to protect electrical loads (such as three-phase motors, heaters, and transformers) from high current damage. It also can monitor electrical current on a main or priority circuit. If the current exceeds a set threshold, the relay cuts off non-priority circuits to prevent breaker trips, then automatically restores them when current drops.

Key Specifications of TRM-25

• Current Range: Adjustable from 0.1 A to 25 A.
• Operating Voltage: 150–260 V AC (50/60 Hz).
• Asymmetry Protection: Features a 50% fixed current asymmetry error to prevent damage during unbalanced phase loads or phase loss.
• Internal Current Transformers: Built directly into the unit, eliminating the need for external current transformers.
• Mounting: Designed for standard DIN rail installation.
• Output Contacts: 5 A / 250 V AC active load.

Working Principle & Operation of the monitoring relay

• Startup Delay: Upon being energized or reset, the device bypasses current control for 5 seconds to accommodate initial motor starting inrush currents.
• Adjustments: Users can set the high current limit using the A> knob and configure the error delay time (0.1–20 seconds) via the t knob.
• Tripping Mechanism: If the current surpasses the configured threshold, the unit tracks the set delay time. Once elapsed, the relay de-energizes, shifting contact output from terminal 3 to terminal 1 and shutting off the "OUT" LED.
• Operation Modes: Features adjustable manual, semi-automatic, or fully automatic reset configurations.