Measuring and Monitoring Relays

Compact monitoring relays for voltage, current, phase-sequence and phase-loss supervision, converting abnormal electrical conditions into dependable contact signals for alarm, interlocking, blocking and auxiliary protection logic.

Product Capability

A modular family of lightweight monitoring relays that continuously supervises key electrical quantities and converts abnormal conditions into clear relay outputs for control, interlocking, alarm and protection-support functions.

Voltage supervision: WY Series monitors single-phase or three-phase AC voltage and can be configured for overvoltage, undervoltage and loss-of-voltage supervision in PT secondary circuits, control-power circuits and interlocking logic.
Phase-sequence and phase-loss supervision: WX Series verifies correct three-phase sequence and phase presence before downstream equipment is permitted to operate, helping prevent reverse rotation and abnormal motor operation.
Current supervision: WL Series monitors circuit current for overcurrent, undercurrent or no-current conditions, supporting heater-circuit supervision, fan and motor load monitoring, CT-current supervision and fault alarming.
Configurable logic: product variants support adjustable thresholds, operate delays and relay-contact outputs so that the monitoring function can be matched to the actual circuit task rather than using a full protection device for a single-function requirement.
Panel-ready design: compact DIN-rail installation, clear local indication and power-system-oriented EMC design simplify panel integration, commissioning and maintenance.

Customer Value

Helps engineers implement focused supervision functions with lower circuit complexity, clearer fault visibility and easier project integration.

Lower system complexity and cost: deploy the specific monitoring element required by the circuit without adding unnecessary protection or automation functions.
Faster commissioning and troubleshooting: local status indication and deterministic relay outputs make abnormal voltage, current, phase-loss and phase-sequence conditions easier to identify.
Improved equipment availability: early detection of undervoltage, no-current, overload, phase loss or wrong phase sequence supports alarm, blocking or controlled shutdown before a small abnormality becomes a larger equipment failure.
Flexible engineering integration: dry-contact outputs can be incorporated into existing control, alarm, interlocking, PLC/RTU and remote-signal circuits, supporting both new designs and retrofit projects.
Consistent project reuse: standardized monitoring functions and configurable settings make it easier to replicate proven circuit logic across switchgear, protection panels, transformer auxiliary panels and industrial control cabinets.

Product Series

Product series are configured according to users' usage and configuration preferences.

WY Series

WY-31 / WY-35; WY-31A4 as a three-phase configuration

Voltage monitoring relays for single-phase or three-phase AC voltage supervision. Depending on the configuration, the series supports overvoltage, undervoltage and loss-of-voltage detection for PT supervision, motor/control-power blocking and electrical interlocking.

WX Series

WX-61

Phase-sequence monitoring relay for three-phase systems. It integrates wrong-phase-sequence and phase-loss detection, with local status indication and relay outputs for motor permissive, interlocking and fault shutdown logic.

WL Series

WL-30 family; WL-31A1 as a representative single-phase configuration

Current monitoring relays for current-present/current-absent, undercurrent and overcurrent supervision. Typical applications include trace-heater current checking, cooling-fan or motor-load supervision, CT-current monitoring and abnormal-current alarms.

View technical parameters by product series.

WY Series — Voltage Monitoring Relays

Parameter(WY)	Data(WY)	Remarks(WY)
Monitoring function	Overvoltage, undervoltage and loss-of-voltage supervision	Function depends on selected WY model/suffix.
Monitoring channels	Single-phase or three-phase	Configuration dependent; WY-31A4 is a three-phase voltage-supervision configuration.
Representative models	WY-31 / WY-35	WY-35 is widely used for PT undervoltage supervision.
Auxiliary power supply	DC 88-370 V / AC 85-265 V, 50/60 Hz	Published value for WY-35 configuration.
Voltage setpoint	0.1-1.0 Un	Published value for WY-35 undervoltage configuration.
Operate delay	0-9999 ms or 0-9999 s	Published value for WY-35; select time unit/range to suit circuit logic.
Measurement / setting accuracy	±3%	Published value for WY-35.
Reset characteristic	Configurable; typical reset level 1.1 × pickup	Published WY-35 configuration; confirm project-specific reset logic.
Output contacts	2 changeover contact groups; 6 A @ 250 VAC / 30 VDC	Published value for WY-35.
Operating temperature	-25 °C to +70 °C	Published value for WY-35.
Humidity	≤95% RH, non-condensing	Published value for WY-35.
Altitude	≤4500 m	Published value for WY-35.
Dielectric / insulation	2 kV dielectric withstand; insulation resistance ≥100 MΩ	Published value for WY-35.
EMC capability	ESD ±15 kV/±8 kV; EFT ±4 kV/±2 kV; surge CM ±4 kV / DM ±2 kV	Published WY-35 test levels.
Terminal capacity	Supports 2.5 mm² crimp-lug double wiring	Published for the WY-30 Series platform.

WX Series — Phase-Sequence Monitoring Relays

Parameter(WX)	Data(WX)	Remarks(WX)
Representative model	WX-61	Three-phase phase-sequence and phase-loss monitoring relay.
Monitoring function	Wrong phase sequence + phase loss	Provides a permissive/safe-state contact logic for downstream control circuits.
Nominal monitored voltage	208-480 VAC	Wide-voltage design for common industrial three-phase supplies.
Operating voltage window	187-528 VAC	Published broad working window for the WX-61 application guide.
Frequency	50/60 Hz, auto-sensing	No separate frequency version required for common 50/60 Hz systems.
Relay operating delay	≤650 ms	Published WX-61 value.
Fault response	≤200 ms	Published WX-61 value for abnormal phase condition response.
Output	2 changeover relay outputs	Used for permissive, blocking, interlocking or controlled-stop logic.
Status indication	RUN and ACT LED indication	Normal and fault states can be checked locally.
Operating mode	WORK / TEST	TEST mode supports commissioning and maintenance checks.
Housing width	22.5 mm	Narrow DIN-rail format for dense control panels.
Mounting	DIN 35 rail	Standard panel installation.
Protection / enclosure	IP20; V0 flame-retardant enclosure	Published WX-61 application-guide data.

WL Series — Current Monitoring Relays

Parameter(WL)	Data(WL)	Remarks(WL)
Monitoring quantity	AC current
Monitoring functions	Overcurrent, undercurrent and no-current supervision	Available function depends on the selected WL model/suffix.
Representative family	WL-30 Series	Lightweight current-monitoring relay family.
Representative model	WL-31A1	Used in ODES solutions for single-circuit current supervision, including trace-heater current monitoring.
Phase / channel configuration	Single-phase or three-phase variants	Select according to the monitored circuit and project wiring.
Setpoint	Configurable by model / project setting	Select threshold according to rated current and required alarm/protection logic.
Operate delay / debounce	Configurable by model	Used to ride through short transients or starting inrush and reduce nuisance operation.
Output	Relay contact output	Can be wired to alarm, blocking, interlocking or remote-signal circuits.
Typical applications	Trace-heater current monitoring; cooling-fan / motor-load monitoring; CT-current supervision	Supports no-current, abnormal-current and overload-related condition detection.
Mounting	DIN-rail modular installation	Designed for control-cabinet integration.
EMC design	Power-system Level-4 EMC design	Series-level capability stated in ODES protective monitoring solution materials.
Model-specific electrical ratings	Confirm from the final WL suffix instruction manual	Current range, exact contact rating and exact delay range vary by selected WL configuration and should be frozen during technical selection.

Resources & FAQ

Datatype - Download
Product Catalog
Installation Drawing
Datasheet
Wiring Diagram
Product Certification Report

Frequently Asked Questions

1. How do I choose between WY, WX and WL monitoring relays?

Choose the series by the electrical quantity and fault condition that must be supervised. Use WY for voltage conditions such as overvoltage, undervoltage or loss of PT/control voltage; use WX for three-phase phase-sequence and phase-loss supervision; use WL for current conditions such as overcurrent, undercurrent or no-current. Then select the specific suffix according to phase count, rated input, setting range, delay and output-contact requirements.

2. What information is required before selecting a specific WY or WL model?

Confirm the monitored circuit type, single-phase or three-phase configuration, nominal voltage/current, required pickup or dropout threshold, operate delay, reset logic, auxiliary supply, output-contact requirement and installation environment. For retrofit projects, the existing schematic and terminal arrangement should also be checked so that the new relay can be integrated without changing the intended control logic.

3. Can a monitoring relay replace the main protection relay or protection IED?

No. These products are intended for focused supervision, alarm, interlocking, blocking and auxiliary protection-support tasks. They are useful where a single or limited monitoring element is required, but they do not replace the main protection device, primary overvoltage protection or other dedicated safety/interlocking systems required by the protection scheme and project standards.

Series-level content above is intended for website product-page organization. Numeric values are shown only where they are available in ODES published technical materials for the referenced configurations. Final ordering codes, current/voltage ranges, contact ratings, timing ranges and wiring must be verified against the instruction manual for the exact model suffix and the project technical specification before release.