Description
The RM4U Voltage Measuring Relay (often branded under Schneider Electric’s Zelio Control / Harmony Control series) is designed to monitor AC or DC supply voltage levels in industrial and automation systems. It detects whether the monitored voltage rises above (overvoltage) or falls below (undervoltage) preset thresholds and changes the state of its relay outputs to initiate protective actions — such as disconnecting loads, signaling alarms, or triggering control sequences.
Depending on the specific model variation (e.g., RM4UA32MW, RM4UA33MW), the relay can operate with a wide measurement range (e.g., 1…500 V AC/DC) and with a supply range from low voltage control supplies (e.g., 24 V AC/DC) up to mains rated supplies (e.g., 220…240 V AC). The relay typically has two changeover (C/O) contacts, rugged silver‑nickel contact material, and an adjustable time delay (for example 0.05 … 30 s) to prevent unwanted tripping during brief transients.
These relays are widely used in motor control panels, distribution boards, power monitoring systems, generators, UPS systems, and battery‑powered applications to ensure the connected equipment operates within safe voltage limits. They are designed to comply with industrial standards for electrical and environmental performance.
📊 Specifications Table (Typical for RM4U Series)
| Specification | Typical Value / Description |
|---|---|
| Product Type | Voltage Measurement / Control Relay |
| Series / Brand | Zelio Control / Harmony (e.g., Schneider Electric) |
| Monitored Parameter | Overvoltage and Undervoltage |
| Measurement Range | Model dependent: e.g., 1…100 V, 10…100 V, 30…500 V AC/DC |
| Supply Voltage | e.g., 24…240 V AC/DC or 220…240 V AC (depends on specific variant) |
| Time Delay Setting | Adjustable ≈ 0.05…30 s (varies by model) |
| Output Contacts | Typically 2 Changeover (2 C/O) relays |
| Max Switching Voltage | Up to 440 V AC |
| Power Consumption | Approx. 1.5…3.5 VA AC (varies) |
| Hysteresis | Approx. 5…30 % of set threshold (adjustable) |
| Contact Material | Silver‑nickel alloy |
| Operating Temp. | Approx. –20…+65 °C |
| Mounting | DIN‑rail or panel depending on housing |
| Protection | IP20 (terminals), IP50 (casing) typical on relay versions |
| Dimensions | Typically 22.5 mm width × ~78 mm height × ~80 mm depth (depends on version) |
🔍 Key Features
-
Real‑time voltage monitoring: Detects both under‑ and overvoltage conditions.
-
Adjustable settings: Thresholds and time delay can be tuned for specific system requirements.
-
Dual relay outputs: Provides two changeover contacts for flexible control logic.
-
Suitable for AC/DC: Many variants support both AC and DC voltage measurement ranges.
-
Industrial ruggedness: Designed for control panels with compliance to standards (IEC, CE, UL, etc.).
📌 Typical Applications
-
Motor protection and control against undervoltage or supply surges
-
Power distribution monitoring to safeguard sensitive loads
-
Generator and alternator output protection
-
UPS and battery systems voltage supervision
-
Automation system voltage control logic
Reviews
There are no reviews yet.