Rotation speed and degree of protection

Rotation speed

The maximum permissible rotation speed of a rotary encoder results from:

  • the mechanically permissible rotation speed,
  • the minimum permissible edge spacing

of the square-wave output signals of the rotary encoder for the follow-on electronics, which results from the tolerance of the phase offset,

  • and the functional rotation speed which is limited by the pulse frequency.

The mechanically permissible rotation speed is specified for each rotary encoder based on the mechanical parameters.

The control electronics generally only allow a certain minimum edge distance between the square-wave output signals. The minimum edge distance is specified for each rotary encoder type based on the electrical parameters.

The functional rotation speed of a rotary encoder is derived from the formula:

nmax = fmax · 10³· 60 / Z

nmax = maximum functional rotation speed [min-¹]

f max = maximum pulse frequency of the rotary encoder or input frequency of the follow-on electronics [kHz]

z = number of lines of the rotary encoder

Degree of protection

All rotary encoders of the industrial types RI 30, RI 36, RI 58, RI 58-H, RI 58-D, RX 70-I and the absolute encoders type AC 58, unless otherwise stated, fulfil the protection class IP65 according to the standards EN 60529 and IEC 529.These specifications also apply to the housing and cable outlet, as well as to device connectors when they are plugged in. The shaft input fulfils the protection class IP64.When the rotary encoder is fitted vertically, however, there must be no standing water at the shaft entrance and ball bearing.

If the standard protection class IP64 is not sufficient for the shaft input, e.g. if the rotary encoder is fitted vertically, the rotary encoders should be protected by additional labyrinth or cup seals.

The rotary encoders are also available with protection class IP67 for the shaft entry and housing on request.