Schneider RM35TF30 Monitoring Relay

Schneider RM35TF30 Monitoring Relay (Harmony / Zelio 3-Phase Control Relay)

 

 

The Schneider RM35TF30 is a 3-phase monitoring relay (voltage + phase protection relay) used to protect motors and electrical systems from phase loss, phase imbalance, wrong phase sequence, and voltage faults.

Product Information

• Brand: Schneider Electric
• Series: Harmony / Zelio Control Relays
• Model: RM35TF30
• Type: 3-phase monitoring relay
• Function: Voltage + phase protection
• Supply voltage range: 220–480 VAC (3-phase systems)
• Output contacts: 1–2 changeover (C/O) relay outputs
• Mounting: DIN rail (35 mm standard)
• Adjustment: Threshold + delay settings (0.1–10s typical)

What it actually is

This is not a PLC and not a control module.

It is a protective monitoring device, meaning:

• It constantly checks the quality of 3-phase power
• If abnormal conditions occur, it trips and changes relay output
• It protects motors and equipment from electrical damage

What it monitors

The RM35TF30 can detect:

• Phase failure (loss of one phase)
• Phase sequence error (wrong rotation direction)
• Phase imbalance
• Overvoltage / undervoltage conditions
• Voltage window faults

System Role (Simple)

3-phase power supply
→ RM35TF30 monitoring relay
→ safety output signal
→ contactor / PLC / shutdown circuit
→ motor protection

So it acts like a “power quality watchdog for 3-phase systems.”

Key Features

• 17.5–35 mm compact DIN rail design
• Adjustable voltage and asymmetry thresholds
• LED indicators (power / fault / relay status)
• Fast response to phase faults
• Prevents motor burning due to bad power conditions
• 2 changeover output contacts for control logic

Typical Applications

• Motor protection systems
• Pumps and compressors
• Conveyor systems
• HVAC equipment
• Industrial power distribution panels
• Automation safety interlock circuits

Advantages

• Prevents costly motor damage
• Simple DIN rail installation
• Adjustable protection parameters
• Works with wide voltage range (220–480V)
• Reliable industrial monitoring

Important Notes

• Not a PLC ❌
• Not a relay for general switching ❌
• Not a contactor ❌
• It is a 3-phase protection / monitoring relay ✔
• It does not power equipment directly—only signals faults

Precautions

• Must be connected to correct 3-phase system only
• Adjust thresholds carefully to avoid nuisance trips
• Do not use as power switching device
• Requires proper wiring of phase inputs (L1/L2/L3)
• Install in ventilated control cabinet