What’s a Permanent Magnet?

Indramat introduced brushless servo motors in 1979. Brushless servos have several advantages over brushed motors: they last longer, they require less maintenance, and they result in less downtime. Indramat’s brushless servo motors are possible because of magnets. These servos use permanent magnets made of rare earth or iron-oxiede magnetic materials, but what’s a permanent magnet exactly?

What’s a permanent magnet?

Some magnets are only magnetic some of the time. Electromagnets produce a magnetic field only when activated, but there’s no on or off switch for a permanent magnet. Permanent magnets differ from electromagnets in that the magnetic field of permanent magnets is constant. It’s always magnetic.

The magnets on your refrigerator, the magnets in your speakers, and that big horseshoe magnet you had as a child are all examples of permanent magnets. If there’s a magnet that continuously produces a magnetic field regardless of your interaction with it, it’s a permanent magnet.

Permanent magnets always produce a magnetic field because they are made of magnetic materials. The molecules in a permanent magnet are organized; the magnetic pull of the atoms line up to generate the magnetic field.

The strongest permanent magnets are made of rare-earth materials. Rare-earth magnets are up to three as powerful as traditional iron magnets.

Permanent magnets in Indramat motors

Indramat servos use permanent rare-earth magnets. Since rare earth magnets can create a stronger magnetic field in a smaller package, they allow servo motors with lower inertia. Powerful permanent motors also mean lighter motors and less maintenance.

Remember that “permanent” refers to a static magnetic field rather than the lifespan of the servo. A permanent magnet does not mean a permanent motor. Indramat servos run for such a long time it may seem as though they’re permanent, but they do need maintenance and service from time to time.

Indramat servos are not serviceable in the field. You must send your unit in for a factory repair. We offer Indramat factory repair services with a 24-hour turnaround, and we have emergency replacement units on hand to keep your system running. Call 479-422-0390 for any of your Indramat service, maintenance, or repair needs.