WARNING
RISK OF ELECTRICAL CHOCK
The STO function does NOT isolate mains voltage to the
frequency converter or auxiliary circuits. Perform work
on electrical parts of the frequency converter or the
motor only after isolating the mains voltage supply and
waiting the length of time specified in the
Safety
chapter
in the relevant Operating Instructions. Failure to isolate
the mains voltage supply from the unit and waiting the
time specified could result in death or serious injury.
•
Do not stop the frequency converter by using the
STO function. If a running frequency converter is
stopped by using the function, the unit trips and
stops by coasting. If this is not acceptable, e.g.
causes danger, stop the frequency converter and
machinery by using the appropriate stopping
mode before using this function. Depending on
the application, a mechanical brake may be
required.
•
STO is suitable for performing mechanical work
on the frequency converter system or affected
area of a machine only. It does not provide
electrical safety. STO should not be used as a
control for starting and/or stopping the frequency
converter.
CAUTION
Automatic restart behaviour is only allowed in 1 of the 2
situations:
•
The unintended restart prevention is
implemented by other parts of the STO instal-
lation.
•
A presence in the dangerous zone can be
physically excluded when STO is not activated.
In particular, paragraph 6.3.3.2.5 of ISO 12100:
2010 must be observed.
WARNING
RISK OF DEATH AND SERIOUS INJURY
The STO function can be used for asynchronous,
synchronous and permanent magnet motors. 2 faults can
occur in the power semiconductor of the frequency
converter. When using synchronous or permanent
magnet motors, a residual rotation can result from the
faults. The rotation can be calculated to angle = 360/
(number of poles). The application using synchronous or
permanent magnet motors must take this residual
rotation into consideration and ensure that it does not
pose a safety risk. This situation is not relevant for
asynchronous motors.
NOTICE
The selection of a stop category in accordance with EN
60204-1 for each stop function must be determined by a
risk assessment:
•
Stop Category 0 is achieved with immediate
removal of power to the actuator, resulting in
an uncontrolled coast to stop. STO according to
EN 61800-5-2 accomplishes a Stop Category 0
stop.
•
Stop Category 1 is achieved with power
available to the machine actuators to achieve
the stop. Power is removed from the actuators
when the stop is achieved according to EN
61800-5-2 Safe Stop 1 (SS1).
•
Stop Category 2 is a controlled stop with power
available to the machine actuators. The stop is
followed by a holding position under power.
NOTICE
When designing the machine application, timing and
distance should be considered for a coast to stop (Stop
Category 0 or STO). For more information regarding stop
categories, refer to EN 60204-1.
Safety
Operating Instructions
6
Danfoss A/S © 09/2014 All rights reserved.
MG37D202
2
2
