2 Engineering
2.8 Safe Torque Off (STO)
Rapid Link 5 · RAMO5 · RASP5 05/20 MN034004EN www.eaton.com 53
2.8.4 STO-compatible installation
DANGER
Make sure to use proper earthing and select cables based on
local regulations or standards.
The variable frequency drive may have a leakage current greater
than 3.5 mA AC or 10 mA DC. In addition, the grounding cable
must be sized for the maximum mains fault current, which is
normally limited by fuses or miniature circuit-breakers. Appropri-
ately sized fuses or miniature circuit-breakers must be installed
at the mains supply for the variable frequency drive in line with
local regulations or standards.
DANGER
The “STO wiring” must be protected against unintended short-
circuits and unintended tampering and modifications. It must be
ensured that the STO input signal is in a safe operating state.
￫
In order to prevent damage to the variable frequency drive, the
devices should remain in their original packaging until right
before they are installed.
They must be stored in a dry and clean area with a temperature
range of -40 °C to 60 °C.
￫
The conductor cross-section used for the STO installation must
be between 0.75 and 2.5 mm
2
.
The length of the cable connected to the control signal terminals
should not exceed 25 meters.
￫
In addition to the wiring guidelines for an installation meeting
EMC requirements, the following requirements must also be
observed for STO wiring:
• The STO-compatible installation must be protected against
short-circuits and tampering. The cables in the STO circuit
can be mechanically protected with a closed cable duct or
with a conduit (ESC = ground and short-circuit-safe installa-
tion).
• The 24 V DC power supply for the STO inputs can be sup-
plied from the RASP5 internal 24 V DC voltage or from an
external 24 V DC power supply. The RASP5 must be wired
as described below.
To Next Page
Loading...
