ABB MicroFlex e190 User Manual

44 Planning the electrical installation
Safe Torque Off
The drive supports the Safe Torque Off function according to standards
EN 61800-5-2; IEC 61800-5-2; EN 60204-1; EN 61508.
The Safe Torque Off function disables the control voltag
e of the power
semiconductors of the drive output stage, thus preventing the inverter from
generating the voltage required to rotate the motor (see diagram below). By using this
function, short-time operations (like cleaning) and/or maintenance work on non-
electrical parts of the machinery can be performed without switching off the power
supply to the drive.
+24 V
X4:4
X4:1
X4:2
U/V/W
Control
circuit
UDC+
UDC-
MicroFlex e190
Output stage
(1 phase shown)
Safe Torque Off
connection
Activation
switch
Notes:
• The STO function is activated when one or both of the safety circuit contacts open. If the period
between both contacts opening or closing exceeds a predefined value, a fault in the safety circuit or
wiring is assumed and an error is reported. See Appendix: Safe Torque Off (STO) on page 187.
• The maximum cable length between the drive and the activation switch is 30 m (98 ft)
WARNING! The Safe Torque Off function does not disconnect the voltage of
the main and auxiliary circuits from the drive. Therefore maintenance work on
electrical parts of the drive or the motor can only be carried out after isolating the
drive system from the main supply.
Note: It is not recommended to stop the drive by using the Safe Torque Off function. If
a running drive is stopped by using the Safe Torque Off function, the drive will stop by
coasting. If this is not acceptable (e.g. causes danger), the drive and machinery must
be stopped using the appropriate stopping mode before using this function.
For further information on the function, see Appendix: Safe Torque Off (STO) on page
187.

ABB MicroFlex e190 Specifications

General

Brand	ABB
Model	MicroFlex e190
Category	Servo Drives
Language	English