Magnetic Latches

Electromagnets can also benefit from incorporating a Permanent Magnet into the design, providing a continuous hold force without having to continuously apply electrical energy. This design ensures that the device continues to magnetically adhere to a particular surface, even if the power is lost.

Applying a small reverse current to the Coil of this device will nullify the force of the Permanent Magnet and release the armature (or other attracted surface).

Typical applications for these devices are medical imaging beds, medical imaging heads and door-locking mechanisms.

Magnetic Latch Mechanisms are bi-stable linear actuators that utilize the energy stored in a compressed spring to provide a much higher linear force than would be possible with a Solenoid of the same size.

The four key components within Magnetic Latch Mechanisms are:

Armature (plunger)
• Internal spring
• Permanent Magnet
• Smaller electrical Coil

Magnetic Latch Mechanisms are at rest in the latched position. To reach this state, the armature must be manually pushed into a position and held in place by a Permanent Magnet. This action also compresses and holds an internal spring. Activation is accomplished by applying a small pulse of electrical current to the otherwise weak electrical Coil. The resulting magnetic field nullifies the holding force of the Permanent Magnet and allows the internal spring to release and move the armature.

Primary advantages of the Magnetic Latch Mechanism include:

• Significantly higher actuation and impact forces than a conventional Solenoid of the same size
• Actuation accomplished with a very small pulse of current
• No electrical energy required to keep the device in the actuated position

Typical applications include fire extinguishing systems and power line interrupter trip mechanisms.

Magnetic Latching Solenoids, often called Bi-Stable Solenoids, are operationally similar to conventional Solenoids—the solenoid armature (plunger) is “pulled-in” by passing electrical current through the solenoid coil.

The Magnetic Latching Solenoid design includes a Permanent Magnet, which holds the armature in the pulled-in (latched) position without the need to continuously apply power to the coil. This power saving feature is a main.

Applying a small reverse current to the Solenoid Coil nullifies the Permanent Magnet, allowing the armature (plunger) to move to the original (un-latched) position. Most often, the return force is provided by a spring that is incorporated into the Solenoid.

Typical applications for Magnetic Latching Solenoids are battery operated and other power critical scenarios such as door-locking mechanisms, computer cabinet locks and electronic circuit breakers.

Benefits of Magnetic Latches

Looking to decrease the operating cost and the thermal output of solenoids in low duty cycles? Choose a magnet latching option from Magnet-Schultz of America. Magnetic latching solenoids, also referred to as bi-stable or open frame solenoids, utilize a permanent magnet to hold the armature in a latched position, eliminating the need to apply continuous power to the coil. This design offers a number of advantages:

  • Reduced power consumption—the actuator can stay in position (either in or out) indefinitely without the constant input power a regular solenoid requires
  • Lower heat—since the solenoid is actuated with a brief burst of power, virtually no heat is generated
  • Battery friendly—the minimal power requirements of magnetic latches make them ideal for use with the small output of a battery power source
  • Greater force—because the return force of the armature is provided by a built-in spring rather than the solenoid itself, magnetic latching solenoids provide higher actuation and impact forces than an unequipped solenoid of the same rating

Typical applications for magnetic latching solenoids (open frame solenoids) include Door Locking Mechanisms, Computer Cabinet Locks and Electronic Circuit Breakers.

To explore the design possibilities of magnetic latching solenoids, contact us for a consultation with a Magnet-Schultz application expert.