An electromagnetic lock (widely known as mag‑lock or EM‑lock) is a popular fail‑safe electronic door‑locking hardware for complete access‑control systems. Different from electric bolt lock which relies on extending mechanical bolt tongue, electromagnetic lock creates strong magnetic attraction force between electromagnet and armature plate, with zero moving mechanical components inside the lock body. It is controlled by relay signal output from access controller and works cooperatively with credential readers such as RFID, fingerprint, facial recognition and keypad readers. Sintronic electromagnetic locks have been deployed for overseas access‑control projects including Nigeria and Saudi Arabia office and commercial‑building reference projects.

Core Working Principle of Electromagnetic Lock

Sintronic electromagnetic lock follows fail‑safe magnetic‑attraction access workflow: Power‑On Magnetic‑Hold (Locked) → Controller Relay Signal Triggers Power Cut‑Off → Door Release → Door‑Close Restore Power & Re‑Lock. Full‑cycle operation steps are described as follows.

1. Standby locked status (power‑on holding)

Under normal working condition, continuous DC12V / DC24V power feeds to electromagnet coil. Strong magnetic force firmly pulls armature plate, keeping door securely locked. Door‑contact sensor monitors door real‑time physical status, waiting for unlock trigger signal from access‑controller relay output.

Important feature: Electromagnetic lock is fail‑safe design: lock stays locked when power is ON; automatically unlocks once power supply is cut off, meeting fire‑emergency evacuation requirements for public buildings.

2. Credential verification and relay‑output trigger

User presents valid credential (RFID card, fingerprint, face, PIN code) to connected reader device. Access controller completes identity‑permission validation. If access is approved, access‑controller relay cuts power supply to electromagnetic lock for preset unlock‑delay duration (configurable 1‑10 seconds).

3. Magnetic force disappears, door releases

When power supply is interrupted, electromagnetic coil loses magnetic attraction force. Armature plate is released, door can be manually pushed open by user.

4. Auto‑re‑lock after door closesAfter user passes through and door leaf returns to fully‑closed position, power supply restores to electromagnetic lock. Magnetic attraction re‑engages, lock returns to standby locked state, ready for next access cycle.

5. Door‑status monitoring & alarm‑trigger processing (with feedback‑signal model)

For electromagnetic lock with door‑contact feedback function: sensor continuously detects door‑leaf position. If door remains open overtime after unlock, or door is forced‑opened without valid credential trigger, feedback signal transmits back to access controller, triggering local buzzer alarm and event‑log record inside ACS‑‑SW management software.

6. Emergency power‑off behaviour

When main power supply fails or fire‑alarm system triggers power‑cut linkage, electromagnetic lock automatically unlocks. Doors can be freely opened for emergency evacuation, complying with public‑building fire‑safety regulations. For sites requiring door‑locked during power‑failure, extra backup‑UPS power supply shall be configured.