Lifting magnets switching systems

Monostable magnet systems are only on or off as long as they are supplied with an electrical or pneumatic switching signal. As soon as this signal is lost, the system switches back to its ‘idle state’. An electro lifting magnet is always monostable and always off when idle. In contrast, permanent systems can be on or off when idle.

Bistable magnet systems switch on or off by a switching signal. This remains until the next switching signal is given. For lifting and hoisting applications, a bistable system is safer than a monostable system because:

• the magnet can never switch off spontaneously, causing the load to fall;
• the magnet actually switches off, and can therefore not unexpectedly attract a steel sheet.

Bistable magnetic systems are always constructed with permanent magnets (or a combination of permanent magnets and electromagnets). All Goudsmit lifting systems are bistable.

Permanent lifting magnets

Permanent lifting magnets can be switched manually, pneumatically or electrically:

• Manually switched
  This type consists of 2 magnets, 1 of which can move with a lever or rotary knob. In the off position, the magnets are shorted so that they cancel each other out. In the on position, the magnets reinforce each other.
  Examples: Magswitch hand lifter  |  Manual permanent lifting magnets  |  Switchable welding magnets
• Pneumatically switched
  The magnet is moved in a housing by means of compressed air so that no magnetism is present outside the housing in the off position, only in the on position (the movement is only internal). See the below image.
  Examples: Magnetic grippers  |  Magswitch grippers  |  Switchable sheet separators  |  Palletizing magnets
• Electrically switchable permanent magnets

Monostable: the permanent magnet section lifts your product. The electromagnet part neutralises the permanent magnetic field and releases the product. This means that the magnet is ‘on’ when it is not supplied with power.

Bistable: an electrical signal rotates two permanent magnets relative to each other, either producing a magnetic field or aligning them such that they cancel each other out. Example: Magswitch wireless electrically switched manual lifting magnet 

Electromagnets

Electromagnets can only be switched electrically with direct current.