Technology of Electrical Relays

Types of Coils

Coils are classified according to the types of magnetic circuits and operational functions.

1. Magnetic circuit

Non-polarized: Operating coils do not have polarity
Polarized: Operating coils have polarity

2. Basic Function

Relay is classified into two basic functions: single-side stable relay and latching relay (also called "Keep" relay)

Single-Side Stable Relay

The contacts turn ON or OFF only when an input signal is received.

Single-Side Stable Relay

Latching (Keep) Relay

The contacts turn ON or OFF when an input signal is received but maintains its contact position during power interruptions.

Latching (Keep) Relay

Select the optimal relay that meets your application and sequence requirements.

Types of Contacts for Electrical Relays

Contacts are classified according to the types of contact forms and contact reliabilities.

1. Contact Forms

There are three types of contact forms: Form A contacts, Form B contacts, and Form C contacts.

Form A contacts ("Make contacts")

This is normally open contact and closes when a voltage is applied to the coil.

Make contacts

Form B contacts ("Break contacts")

This is normally closed contact and opens when a voltage is applied to the coil.

Break contacts

Form C contacts ("Transfer contacts")

Combines the Form A and Form B contacts in a single relay and when a voltage is applied to the coil, Form C contact moves away from Form B contact and connects with Form A contact (for single-side stable relays).

Form C contacts (Transfer contacts)

2. Electrical Relay Contact Reliability

Contact configurations are classified into three types according to the reliability level: Single contact, Twin contact and Cross-bar Twin contact.

Contact reliability

Types of Terminals for Electrical Relays

The terminal configurations are classified as follows:

Types of Terminal Terminal configuration Typical Relay Model
Plug-in terminal Plug-in terminal
on maintenance,Lineup of dedicated sockets
MY
MY
PC board terminal PC board terminal
PC board (through hole) mount type
G5NB
G5NB
Screw terminal Screw terminal
Emphasis on maintenance,Screw terminal connection
G7Z
G7Z
Surface-mount terminal Surface-mount terminal
PC board (surface-mount) automatic mount type
G6K(-F/G)
G6K(-F/G)
Quick connect terminal Quick connect terminal
Emphasis on maintenance,Tab terminal connection
G2R-T
G2R-T

Enclosures for Electrical Relays

The terminal configurations are classified as follows:

× : Penetration exist
○ : No penetration
△ : Penetration may exist

Enclosures Characteristics Atmosphere Conditions Typical Relay Models
Dust and dirt Harmful gas
Flux resistant type(PCB relay) This type of structure prevents solder flux penetration into the interior. △(Protects from large amounts of dirt and dust)   × G2R
G2R
Palstic Sealed(PCB Relay) This type of structure prevents solder flux and cleaning solvent penetration. G5Q
G5Q
Unsealed(Plug-in Relay) This type of structure places the relay inside a case to protect against foreign substances. × MY
MY
Plastic Sealed(Plug-in relay) This type of structure places the relay with resin case and cover to minimize corrosion effects. G2A
G2A
Hermetically sealed(Plug-in relay) This type of structure places the relay in a corrosion resistant sealed case using metal or glass purged with inert gas (N2) to protect from corrosive gas penetration. MYH
MYH

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Product Lineup of Relays