relay
Enable an AI agent to recognise an electrical relay, assess whether its switching behaviour is suitable and trustworthy, and determine permitted testing, operation or replacement.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise an electrical relay, assess whether its switching behaviour is suitable and trustworthy, and determine permitted testing, operation or replacement.
An electrically operated switching device that produces a predetermined, usually abrupt change in one or more output circuits when specified conditions are met in its controlling input circuit(s), typically isolating the control circuit from the load.
It can be Identify the relay and map its control and switching terminals from verified documentation.; Assess compatibility with a proposed control supply and switched load.; Command, set or reset the relay when the connected circuit permits the resulting transition.; Test output behaviour against the input command using a procedure suitable for the relay technology.; Investigate unexpected switching, failure to switch or excessive heating.; Select a replacement using verified electrical, behavioural, mounting and application constraints..
Distinguishing features
Determine whether an electrical control input governs a distinct electrical switching output, rather than the device being solely a manually operated switch.
Distinguish a packaged relay from a bare switching semiconductor by identifying its declared device role, control interface and output interface.
Check whether the manufacturer identifies the device as a relay or contactor; do not decide from physical size or a guessed current threshold.
Determine whether the device primarily switches on command or evaluates electrical conditions to issue protection commands, which may require a neighbouring protective-device model.
Confirm that relay denotes a physical electrical device in this registry rather than a communications intermediary.
Scope
+ Relay identity, operating technology and control-to-output relationship
+ Control input requirements and switching or retention behaviour
+ Output arrangement, connected load and applicable switching limits
+ Terminal assignments, electrical separation and installation dependencies
+ Observed operation, failure evidence and permitted interventions
- Communication relays, software relays and human relay activities
- The complete circuit, machine or process that the relay controls
- The internal construction and condition of the switched load
- Upstream control logic and system-level protection coordination
- Whole-system safety certification and maintenance policy
Characteristics
- Operating technology
- Electromechanical, reed, solid-state, hybrid, other documented type, unknown Determines which operating observations, output states and failure tests are meaningful.
- Control input specification
- V AC or DC, Hz where applicable, A or W; documented operating range Establishes whether the available control signal can operate the device without exceeding its limits.
- Output arrangement
- Documented pole and throw arrangement, contact forms, or semiconductor output configuration Identifies which circuits can be connected, disconnected or transferred.
- State retention
- Non-latching, latching with documented set/reset behaviour, other, unknown Determines whether removing the control input establishes a predictable output state.
- Observed switching state
- Per-output conducting, non-conducting, transitioning, indeterminate; paired with control input and observation time Allows comparison of requested and actual behaviour without equating an indicator with output confirmation.
- Load-dependent switching limits
- V, A and applicable load category, AC/DC conditions, inrush and duty constraints Supports suitability decisions using the actual load conditions rather than one headline rating.
- Switching timing
- ms for specified operate, release, reset or transfer events under stated conditions Determines whether switching meets the controlled circuit's timing requirements.
- Terminal and circuit assignments
- Terminal-to-control, output, common, protective connection and external circuit mappings Supports correct connection, interpretation of measurements and replacement.
- Electrical separation specification
- Documented separation between named circuits, associated ratings and evidence; unknown where unverified Prevents treating every relay output or off state as an isolation boundary.
- Installation temperature
- °C at the documented ambient, case or mounting reference point Supports assessment of thermal constraints and any applicable load derating.
Also called
Where this came from
wikidata · CC0 1.0
Also registered as vr.tr.relay
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 24 questions.
Relay identity and role Establishes what device is present and which interpretation of relay applies.
A relay label alone does not establish its technology, behaviour or boundary with neighbouring switching and protection devices.
Device identification
Connects the physical device to evidence for its exact variant.
Variant and technology
Record identifying markings, operating technology and the documentation supporting the variant assignment.
- Which manufacturer, part number and variant markings identify this relay? provenance
- What operating technology does documentation establish, and which details remain unknown? definition
Switching role
Locates the device between its control source and the circuits it switches.
Control and output boundary
Record the device's switching role and distinguish it from the surrounding controller, load and protection functions.
- Which input controls which outputs, and what external circuits do those outputs serve? definition
- What evidence places this device within relay rather than contactor, switch or protective-device scope? boundary
Control and state behaviour Describes how electrical input and prior state determine switching outcomes.
An agent must predict the effects of energisation, input removal and reset without assuming all relays return to a resting state.
Input and actuation
Captures the electrical conditions and command sequence required for operation.
Valid control command
Record the input range, polarity or waveform requirements and any required pulse or sustained command.
- What input voltage, waveform, polarity and duration are specified for operating this variant? measurement
- What command sequence operates or resets it, including any separate set and reset inputs? action
Output state and timing
Captures output states, transition timing and dependence on previous commands.
Command-to-output response
Record expected and measured output behaviour for input application, removal and restoration.
- What output state is specified after input removal or restoration, and does it depend on retained state? definition
- Under the stated test conditions, what output transitions and timing were actually observed? measurement
Switched circuit compatibility Relates output construction and ratings to the connected electrical load.
Switching suitability depends on topology, load behaviour and separation requirements, not merely nominal current.
Output topology and separation
Records output paths, terminal meanings and documented electrical boundaries.
Output paths and off state
Record terminal connectivity in each relevant state and evidence for off-state and isolation properties.
- Which terminals conduct in each defined state, and what reference state defines any normally open or normally closed labels? definition
- What documentation establishes separation between circuits and any off-state leakage or residual conduction? provenance
Load and duty envelope
Compares actual switching demands with the applicable device limits.
Application-specific rating
Record the ratings applicable to the load's electrical behaviour, switching frequency and installation conditions.
- What voltage, steady current, inrush and load characteristics must each output switch? measurement
- Which documented ratings, thermal conditions and duty limits govern whether this load may be connected? boundary
Condition and intervention Connects relay-specific failure evidence to testing, operation and replacement decisions.
A control signal or operation indicator alone cannot establish that the switched circuit reached its intended state.
Switching health
Evaluates whether outputs respond correctly and remain within relevant condition limits.
Verified output condition
Record independent output observations and technology-appropriate evidence of deterioration or failure.
- What measurements confirm actual output conduction or interruption independently of the command or indicator? measurement
- What evidence supports or rules out relevant faults such as welded contacts, failure to actuate, semiconductor failure or excessive heating? measurement
Testing and replacement
Defines the conditions under which the relay may be exercised, disconnected or substituted.
Permitted relay intervention
Record circuit-dependent permission to change output state and the criteria for a suitable replacement.
- What isolation, load-state and control-inhibit conditions must hold before testing, manually operating or removing this relay? action
- Which control, output, retention, timing, separation and mounting properties must a replacement preserve? boundary
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Electromechanical armature (elementary) relay
- Reed relay
- Solid-state relay (SSR)
- Latching / bistable relay
- Time-delay relay
- Protective (measuring) relay
- Thermal / overload relay
- Safety relay
- Which of these kinds and varieties hold for the sense of relay this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q128211 - Item for the electrical relay (switching device).
- HS (Harmonized System) - 8536.41 (voltage ≤ 60 V); 8536.49 (other relays) - Customs heading for electrical relays under apparatus for switching.
- UNSPSC - 39122300 - Commodity class Relays (and more specific child codes for types).
- IEC 60617 / IEEE Std 315 graphical symbol - IEC 60617-S00328 and related contact/coil symbols - Schematic identity on electrical drawings, not a product SKU.
- Which of these identifiers and schemes hold for the sense of relay this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- IEC 60050-444 (IEV) - International Electrotechnical Commission: vocabulary for elementary relays
- IEC 61810-1 - IEC: electromechanical elementary relays, general and safety requirements
- IEC 61812-1 - IEC: time relays for industrial use
- IEC 62314 - IEC: solid-state relays
- IEC 60255 series - IEC: measuring relays and protection equipment
- IEC 60947-4-1 / IEC 60947-5-1 - IEC: contactors, motor-starters, and control-circuit devices (boundary with relays)
- UL 508 / CSA C22.2 No. 14 - UL / CSA: industrial control equipment listing in North America
- EN 61810 (harmonized) and Low Voltage Directive 2014/35/EU - CENELEC / EU: CE marking of relays as electrical equipment
- IEEE C37 series (e.g. C37.90, C37.2 device function numbers) - IEEE: protective-relay performance and numbering in power systems
- Which of these standards and regulation hold for the sense of relay this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- PLC or microcontroller GPIO driving a coil or SSR input to switch mains loads, motors, heaters, lamps, and valves while galvanically isolating the logic side.
- Automotive fuse-box and body-control modules using ISO mini/micro plug-in relays for lighting, starter, fuel pump, and HVAC.
- Power-system protection: overcurrent, differential, and distance relays tripping circuit breakers on faults.
- Machine-safety circuits using force-guided (positively driven) contacts and safety relays to implement e-stop and guard interlocking.
- Telecom and test equipment using reed and mercury-wetted relays for low-level analog and RF signal switching.
- Building HVAC and lighting contactors/relays in distribution boards and BMS panels.
- Which of these real-world use hold for the sense of relay this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Coil / control voltage - 5-24 V DC logic; 12/24 V automotive; 24/48/110/230 V AC/DC industrial - V
- Contact switching current - signal: mA-2 A; power PCB/plug-in: 5-30 A; contactors higher - A
- Contact switching voltage - 30 V DC signal; 250-400 V AC power; some DC up to hundreds of volts - V
- Operate / release time (EMR) - 2-15 ms typical; reed faster; SSR half-cycle to a few ms - ms
- Mechanical / electrical endurance - 10^5-10^7 mechanical operations; electrical life much lower at rated load - operations
- Dielectric / isolation voltage - 1-5 kV coil-to-contact common for reinforced isolation parts - V
- Contact resistance (new) - 10-100 mΩ power contacts; milliohms to ohms for dry reed/signal - Ω
- Power dissipation (coil or SSR) - 0.2-1.5 W coil; SSR heat follows load current and on-state drop - W
- Which of these typical measurements hold for the sense of relay this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Contact welding or sticking under inrush (lamps, motors, capacitive loads) so the load stays energized.
- Contact erosion, pitting, and high resistance from arcing, especially on DC inductive loads without suppression.
- Coil open-circuit, insulation failure, or overheating; SSR fail-short (typical) leaving the load on.
- Contact bounce causing false counts, logic glitches, or premature wear.
- Insulation breakdown or creepage failure causing shock or mixing of SELV and mains circuits.
- Nuisance trip or failure-to-trip of protective relays, leading to outages or uncleared faults and fire.
- Safety-relay defeat or welded contacts defeating e-stop if force-guided contacts and monitoring are not used.
- Audible chatter and coil AC hum; residual magnetism preventing release.
- Which of these failure modes and hazards hold for the sense of relay this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- North America commonly specifies UL 508 / NEC panel practice and automotive ISO mini relays; coil voltages 24 V DC and 120 V AC are typical.
- IEC / Europe uses EN 61810, 24 V DC industrial control as the default, and CE/LVD; 'contactor' is more sharply distinguished from 'relay' by utilization category (AC-1/AC-3).
- Power-system protective relays follow IEEE C37 device numbers in North America and IEC 60255 / IEC 61850 in much of the rest of the world.
- Automotive form factors: ISO 280 mini/micro in most markets; some Japanese and older vehicles use different footprints.
- The word 'relay' in telecom historically meant a repeater or microwave hop, not a switching component; that sense is still used in radio and network engineering.
- Which of these regional variation hold for the sense of relay this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Contactor - A contactor is a high-current, high-endurance electromechanical switch for motors and power circuits, usually with large contacts, arc chutes, and utilization categories (IEC 60947-4-1); a control relay is for signalling or modest loads (IEC 61810). Overlap exists at the low-power end.
- Solid-state switch / TRIAC / MOSFET driver (not packaged as an SSR) - An SSR is a complete isolated module with specified isolation, I/O ratings, and often zero-cross switching; a bare TRIAC or FET on a PCB is not an SSR unless those ratings and isolation are designed and claimed.
- Circuit breaker - A breaker is a protective overcurrent device that opens on fault and is reset by an operator or mechanism; a relay (except a protective relay driving a breaker) is a commanded switch and does not itself provide overcurrent interruption ratings like a breaker.
- Optocoupler / isolator - An optocoupler transfers a signal across isolation without a load-switching output; a relay's purpose is to switch a load circuit. SSRs often contain an optocoupler as the isolation element.
- Solenoid / actuator - A solenoid converts current into linear mechanical motion for a valve or latch; a relay uses similar electromagnetic actuation but the useful output is electrical contacts (or a semiconductor switch), not mechanical work.
- Repeater / radio relay - In communications, a relay is a station that receives and retransmits a signal; it is not an electromechanical or solid-state switching component. Domain PHY.OBJ here is the switching device.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of relay this model covers, and on what evidence? provenance
Sources
- IEV 444: Elementary relays - IEC vocabulary definition of an elementary relay as a device producing sudden predetermined changes in output circuits when input conditions are fulfilled.
- IEC 61810-1: Electromechanical elementary relays - Part 1: General and safety requirements - Product standard covering electromechanical elementary relays, ratings, and safety requirements used in industrial and appliance control.
- IEC 62314: Solid-state relays - Product standard distinguishing solid-state relays from electromechanical types and stating ratings and performance tests.
- IEC 60255 series: Measuring relays and protection equipment - Standards family for power-system protective relays, distinct from elementary control relays.
- UL 508: Standard for Industrial Control Equipment - North American listing practice for industrial control relays and related equipment.
What the second pass must settle
- Does vr.tr.relay specifically denote electrical relays, given that the registry records no definition?
- Does this entry include solid-state, reed, time-delay and protective relays, or are some owned by separate registered things?
- What authoritative registry distinction separates relay from contactor and other electrically controlled switching devices?
- Which existing Vercy model, if any, already owns this concept and should be reused instead of creating another model?
- Which manufacturer documents and application requirements should establish technology-specific condition thresholds and permitted interventions?