CMW112 Precision Current Relay (Industrial-Grade Overcurrent & Undercurrent Monitor)

Protect your critical motors, generators, and transformers from electrical faults with the Woodward CMW112, a dual-threshold current monitoring relay engineered for demanding industrial environments. Covering a measurement span of 0.1A to 100A with ±2% accuracy, this relay detects both overcurrent and undercurrent conditions before they escalate into costly equipment failures or unplanned downtime.

Designed for maintenance teams and electrical engineers managing power distribution systems, the CMW112 combines fast fault detection with intelligent time-delay filtering to eliminate nuisance trips during motor startup or transient load changes. Whether you're safeguarding a single pump or orchestrating protection across an entire facility, this relay delivers the reliability and flexibility modern operations demand.

With universal 24-240V AC/DC power input, compact DIN rail mounting, and front-panel LED diagnostics, the CMW112 integrates seamlessly into new installations or retrofit projects—no specialized tools or proprietary software required.

Core Features & Business Value

→ Dual Independent Setpoints
Configure separate high-current and low-current thresholds with dedicated relay outputs. Use one channel for early-warning alarms and the second for emergency shutdown—maximizing asset protection while minimizing false trips.

→ Programmable Time Delay (0.1-30s)
Filter out harmless inrush currents during motor starts or brief load spikes. Adjustable delay ensures genuine faults trigger protection while normal operations continue uninterrupted, reducing maintenance callouts by up to 40%.

→ Universal Voltage Compatibility
Single model supports 24-240V AC/DC power systems, eliminating inventory complexity and simplifying spare parts management across multi-site operations.

✓ Tool-Free Configuration
Front-mounted potentiometers allow technicians to adjust current thresholds and time delays in seconds—no laptop, no software licenses, no downtime.

✓ Compact DIN Rail Design
Occupies just 22.5mm of panel width, freeing up valuable space in crowded control cabinets for additional I/O or safety devices.

✓ Visual Fault Indication
Multi-color LEDs display power status, relay states, and active alarms at a glance, accelerating troubleshooting during emergency response.

Typical Application Scenarios

Manufacturing Production Lines
Challenge: Conveyor motors experiencing intermittent overload due to material jams.
Solution: CMW112 detects sustained overcurrent (>110% rated) and triggers an alarm before thermal damage occurs, while ignoring brief 2-second spikes during product transitions.
Result: 60% reduction in motor replacements and elimination of mid-shift production stoppages.

Water Treatment Facilities
Challenge: Submersible pumps running dry when intake levels drop, causing rapid motor burnout.
Solution: Low-current threshold detects the 30-40% drop in amperage characteristic of dry-run conditions, shutting down the pump within 5 seconds.
Result: Extended pump lifespan from 18 months to 5+ years, saving $12,000 annually in replacement costs.

Data Center Backup Generators
Challenge: Diesel generators overloading during utility transfer, risking shutdown during critical operations.
Solution: CMW112 monitors generator output current and activates load-shedding relays when approaching 95% capacity, maintaining stable power delivery.
Result: Zero unplanned outages during 24-month deployment across 8 facilities.

HVAC Chiller Systems
Challenge: Compressor motors drawing excessive current due to refrigerant leaks or bearing wear.
Solution: Gradual current increase triggers maintenance alert at 105% threshold, allowing scheduled repairs before catastrophic failure at 120%.
Result: Shift from reactive to predictive maintenance, reducing emergency service calls by 75%.

Technical Parameters & Selection Guide

Selection Criteria: Match the relay's measurement range to your CT secondary rating (1A or 5A). For three-phase systems, deploy one CMW112 per phase or use a single unit with a summation CT for total load monitoring. In high-vibration environments (>2g), add supplementary terminal strain relief.

Extended Functions

SCADA Integration: Relay outputs interface directly with PLC digital inputs or alarm annunciator panels. For remote monitoring, pair with Modbus RTU gateways to transmit fault status to centralized control rooms.

Cascaded Protection Schemes: Combine with complementary Woodward relays for comprehensive electrical protection. The Woodward IRI1-I5E05D Current Relay handles basic single-phase monitoring, while the Woodward MRI4A0AB Multifunction Protection Relay adds voltage and frequency protection. For feeder circuits, the Woodward MRI3I5E5DM Digital Feeder Protection Relay provides complete distribution protection.

Custom Calibration: Factory calibration available for non-standard CT ratios or specialized current ranges (consult technical support for lead times).

Delivery Timeline & Service Guarantee

Standard Delivery: 3-5 business days for in-stock units via express courier (DHL/FedEx). Tracking provided within 24 hours of order confirmation.

Custom Configuration: 10-15 business days for factory-programmed setpoints or special voltage variants.

Warranty Coverage: 12-month manufacturer warranty against defects in materials and workmanship. Warranty includes free replacement and covers return shipping costs.

Technical Support: Lifetime application engineering assistance via email (response within 4 hours during business hours) or phone consultation for complex integration projects.

Documentation Package: Every unit ships with installation manual, wiring diagrams, CT selection guide, and sample ladder logic for common PLC platforms (Allen-Bradley, Siemens, Mitsubishi).

Frequently Asked Questions

How do I size the current transformer for my application?
Select a CT with a primary rating 20-30% above your maximum expected load current. For a 75A motor, use a 100:5 CT. The CMW112 accepts both 1A and 5A secondary CTs—configure the scaling via the front-panel range selector.

Can this relay protect against single-phasing in three-phase motors?
Yes, when monitoring all three phases with separate CMW112 units. A phase loss causes current imbalance—the affected phase drops while others rise. Configure low-current alarm on each phase to detect this condition within 0.5 seconds.

What's the difference between overcurrent and overload protection?
Overcurrent protection (CMW112's function) responds to instantaneous current exceeding a threshold, ideal for short-circuit or locked-rotor faults. Overload protection uses thermal models and is typically handled by motor starters. Use both for comprehensive protection.

Does the relay require periodic recalibration?
No field calibration needed. Factory calibration remains stable for 10+ years under normal operating conditions. Annual verification against a calibrated ammeter is recommended for critical safety applications.

Can I monitor DC current with the CMW112?
No, this model is AC-only (50/60Hz). For DC current monitoring in battery systems or solar inverters, contact our technical team for alternative Woodward solutions designed for DC applications.

What happens if auxiliary power is lost?
Relay outputs de-energize (fail-safe mode). When power returns, the relay auto-resets after a 2-second initialization. For critical applications requiring maintained state during power loss, specify latching relay outputs (custom order).

Ready to Protect Your Equipment?

Order your Woodward CMW112 Current Monitoring Relay today and eliminate the risk of unexpected motor failures. Our technical team is standing by to assist with CT selection, wiring configurations, or integration questions.

Contact us now: Email sale@ninermas.com or call +0086 187 5021 5667 for same-day quotations and application support.

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