Data Sheet for Product

Siemens Building Technologies CA1N4028 / 11.1998

Landis & Staefa Division 3/12

Conversion from electrical to mechanical energy

a) Magnet voltage

→

magnetic force

In the ferromagnetic circuit, which consists of the casing (yoke) and the

moving core, the voltage applied to the coil (Fig. 3) produces a magnetic

field. Where the greatest magnetic resistance occurs – in the air gap – this

field causes a force of attraction which becomes stronger as the voltage

increases.

94.0207

Coil (a)

(armature)

Casing

(yoke)

Air gap

Pole

Core

(b)

Fig. 5: The magnetic field in the ferromagnetic circuit

b) Magnetic force

→

counterforce

→

stroke

The magnetic force acts to overcome the force of a counterspring. The core

now moves in the direction of the stroke until the magnetic force and that

of the spring are equal. There is thus a defined stroke for each voltage signal

applied.

Due to the special construction of the ferromagnetic circuit there is a linear

relationship between increases in voltage and the stroke.

94.0209

Magnet voltage

Magnetic field

Spring force

Stroke

Spring

constant

[H]

U [V]

Fig. 6: Relationship between stroke (H) and voltage (U)