Permanent Magnets | General

Permanent magnets have a consistent non-varying magnetic field that has a north and south pole associated with them.  The magnets come in different materials – rare earth, Alnico and hard ferrite.  They all come in different sizes and shapes and have different magnetic strengths. The rare earth are the strongest, Alnico are the most stable, and ferrite are the least expensive. The magnetic strength is generally measured in gauss or milliTesla.

A Reed Switch requires either a permanent magnet or magnetic field in order to activate the switch, thus it is commonly called a magnetic reed switch. Magnets have reversible and irreversible demagnetization specifications. Engineers should consider shock, vibration, strong external magnetic fields as well as high temperatures in their designs. All these factors influence the magnetic force and the long term stability in different ways.

Preferably the magnet is mounted on the moving part of the application. Professional tuning of magnet and reed switch pairing can improve the functionality of the whole sensor-magnet system.

Types of Magnets

We offer the following types of permanent magnets:

• AlNiCo (Aluminum Nickel, Cobalt, Iron and Titanium)
• SmCo (Samarium–Cobalt) & NdFeB (Neodymium) - rare earth
• Hf - hard ferrite

These are some of our most widely used models, others available as required.

• AlNiCo - Ø2.5 x 12.7 mm, Ø3.0 x 12.0 mm, Ø4.0 x 19.0 mm, Ø5.0 x 4.0 mm, Ø5.0 x 20.0 mm, Ø5.5 x 22.0 mm, Ø7.5 x 27.0 mm, 3.2 x 3.2 x 19.0 mm
• Rare Earth - NdFeB N35 Ø4 x 19 mm, NdFeB N35H Ø4 x 19 mm, NdFeB N45 Ø4 x 19 mm, NdFeB 250/175H Ø6 x 10 mm, NdFeB 250/175H 10 x 5 x 1.9 mm, SmCo5 Ø1.9 x 3 mm, SmCo5 Ø3 x 4 mm
• Hard Ferrite - 28/26 2.6 x 2.6 x 4.0 mm, 28/26 3.5 x 1.8 x 1.8 mm, 28/26 6.7 x 6.7 x 2.7 mm

Magnets have reversible and irreversible demagnetization specifications. Be especially careful with shock, vibration, strong and close external magnetic fields as well as high temperatures. All these factors influence the magnetic force and the long term stability in different intensities. Preferably the magnet is mounted on the moving part of the application. Professional tuning of magnet and reed switch can improve the functionality of the whole sensor-magnet system.

Costs	Ferrite	AiNiCo	NdFeB	SmCo
Energy (WxHmax.)	Ferrite	AiNiCo	SmCo	NdFeB
Working Temperature	NdFeB	Ferrite	SmCo	AiNiCo
Corrosion - Resistant	NdFeB	SmCo	AiNiCo	Ferrite
Opposing Field - Ressistant	AiNiCo	Ferrite	NdFeB	SmCo
Mecanical Strength	Ferrite	SmCo	NdFeB	AiNiCo
Temperature Coefficient	AiNiCo	SmCo	NdFeB	Ferrite