What is the task of a pulley/deflection roller when using with a wire draw encoder?

With the aid of deflection rollers, it is possible to guide the measuring wire of wire draw encoders over edges and around corners without significantly affecting the lifetime of the wire draw encoder.

In this case, it must be considered that the designs of the deflection roller and of the measuring wire must be compatible in order to avoid damaging the system.

Recommendations:

• The groove radius should not be too small – recommendation: 0.53 x diameter of the wire cable
  
• The groove opening angle should be neither too small nor too large – recommendation: 60°
  
  
• In order to ensure the longest possible system life, the deflection roller material should be neither too soft nor too hard – recommended material: polyamide
  
  
• The groove base diameter of the deflection roller should not be too small – see table for recommendations

General notes on the installation of deflection rollers

The deflection roller should always be installed in a way which ensures that running is smooth. The deflection roller should ideally have an integrated ball bearing.

The smaller the deflection angle (α) achieved by a deflection roller, the less wear will appear on the measuring wire and therefore the longer the service life of the wire draw mechanism.

If two or more deflection rollers are needed, then the deflection rollers should always be installed at some distance from one another. The requisite distance between the deflection rollers must be accurately defined on site, accounting for specific customer requirements.