INDUSTRY COMPONENT

Auxiliary Contacts

Auxiliary contacts are electrical switching devices used in industrial control systems to provide additional control signals, status indication, or interlocking functions for main power contactors.

Component Specifications

Definition
Auxiliary contacts are supplementary electrical contacts mechanically linked to the main contacts of a power contactor or relay. They operate simultaneously with the main contacts but handle lower current ratings, typically ranging from 5A to 10A. These contacts are used for control circuit functions such as signaling, interlocking, sequencing, and providing feedback about the status of the main contactor. They come in various configurations including normally open (NO), normally closed (NC), and changeover (CO) contacts, with different contact materials and mounting options to suit various industrial applications.
Working Principle
Auxiliary contacts operate through mechanical linkage to the main contactor's actuation mechanism. When the main contactor coil is energized, it creates a magnetic field that moves the armature, which simultaneously closes or opens both the main power contacts and the auxiliary contacts. The auxiliary contacts are electrically isolated from the main power circuit and are designed to handle control signals rather than power loads. They provide reliable switching action synchronized with the main contactor operation, enabling complex control logic without requiring separate switching devices.
Materials
Contact materials: Silver alloy (AgCdO, AgSnO2) or silver-nickel (AgNi) for low to medium current applications; Silver-tin oxide (AgSnO2) for higher reliability; Contact carriers: Thermoplastic (PBT, PA66) with UL94 V-0 rating; Terminals: Brass or copper alloy with tin or silver plating; Springs: Stainless steel or phosphor bronze; Housing: Thermoplastic with flame-retardant properties.
Technical Parameters
ParameterTypical rangeNotes & selection driver
Mounting TypeSnap-on, screw, or DIN rail
Rated Current5A to 10A at 240V AC
Rated VoltageUp to 600V AC/DC
Electrical Life1,000,000 operations minimum
Mechanical Life10,000,000 operations minimum
Contact Resistance<50 mΩ
Dielectric Strength2500V AC for 1 minute
Contact ConfigurationNO, NC, CO (1NO1NC, 2NO, 2NC, etc.)
Insulation Resistance>100 MΩ at 500V DC
Operating Temperature-25°C to +70°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards
ISO 60947-5-1, DIN EN 60947-5-1, IEC 60947-5-1, UL 508

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Contact welding due to excessive inrush current
  • Mechanical failure from vibration or shock
  • Insulation breakdown from moisture or contamination
  • Incorrect contact configuration causing control circuit malfunctions
  • Overheating from poor connection or excessive current
FMEA Triads
Trigger: Contact contamination from dust, oil, or chemical vapors
Failure: Increased contact resistance leading to overheating and circuit failure
Mitigation: Use sealed contact blocks, regular cleaning, and proper environmental protection
Trigger: Mechanical wear from frequent operation
Failure: Contact misalignment or failure to make proper connection
Mitigation: Regular inspection, use of contacts with higher mechanical life rating, and proper lubrication of moving parts
Trigger: Electrical overload beyond rated capacity
Failure: Contact welding or arcing damage
Mitigation: Proper sizing for application, use of protective devices, and regular current measurement

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance
Contact gap: ±0.2mm; Contact overtravel: ±0.3mm; Operating force: ±10% of nominal value
Test Method
Dielectric test: 2500V AC for 1 minute between contacts and ground; Contact resistance test: 6V DC, 1A maximum; Mechanical endurance test: 10,000 operations at rated frequency; Electrical endurance test: 1,000 operations at rated load

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation
Request current drawings, revision history, and a signed specification sheet.
Manufacturing capability
Verify equipment lists, process limits, capacity, and representative production evidence.
Inspection readiness
Confirm test methods, calibrated equipment, sampling plans, and traceable reports.
Supplier transparency
Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Auxiliary Contacts

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

MAXGE Electric Technology Co., Ltd.
Zhejiang, CN
Founded 2006133,000 m²
Also makes: Feed Box, Motor Starter, Circuit Breaker and 4 more
Listed on the company's own website · profile compiled by CNFX from public sources
Listed there as: “SGLW30 Auxiliary contacts”
View source page ↗ maxge.com · checked 2026-08-26

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Share this page

Related Components

Marking Strip
A durable marking strip used for terminal identification in motor terminal blocks to ensure proper electrical connections and safety compliance.
Gland Body
A gland body is the main housing component of an aluminum cable gland that provides mechanical protection and environmental sealing for electrical cables entering enclosures.
Current Sense Resistor
A precision resistor used to measure current flow in electrical circuits by converting current to a measurable voltage drop.
Conductor Terminal
A conductor terminal is a critical electrical component designed to securely connect and terminate conductors in high-voltage insulating bushings, ensuring reliable electrical transmission and insulation integrity.

Frequently Asked Questions

What is the difference between normally open and normally closed auxiliary contacts?

Normally open (NO) contacts remain open when the main contactor is de-energized and close when energized. Normally closed (NC) contacts remain closed when de-energized and open when energized. NO contacts are typically used for status indication or starting auxiliary circuits, while NC contacts are used for safety interlocking or stop circuits.

Can auxiliary contacts be added to existing contactors?

Yes, most industrial contactors are designed with modular auxiliary contact blocks that can be snapped onto the main contactor body. These add-on blocks provide additional contacts without requiring complete contactor replacement. The number of add-on blocks is limited by the contactor design and manufacturer specifications.

What maintenance do auxiliary contacts require?

Regular inspection for contact erosion, cleaning of contact surfaces with appropriate solvents, checking for proper mechanical operation, and verifying electrical continuity. Contacts should be replaced when erosion exceeds 50% of the original thickness or when contact resistance increases significantly.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Request Manufacturing Insight for Auxiliary Contacts

Thank you. Your request has been sent. We'll respond within 1–3 business days.
Sorry, we couldn't send your message. Please try again, or email us at [email protected].
Armature Windings Backshell Body
Get QuotesChat