Installation Precautions; Soft Starter Protection - Siemens SIKOSTART 3RW34 Instructions De Service

Installation
3. When mounting the soft starter in an enclosure, the enclosure must be properly sized or ventilated to provide
Order No.
3RW34 52/54
3RW34 55 - 65
3RW34 66 - 67
3RW34 68 - 83
3RW34 84 - 86
Table 4 : Ventilation Cross-Sections
Locate front ventilation air inlet vent at least 3 inches (75 mm) below the bottom edge of the soft starter. Locate the
outlet air vent area at least 6 inches (150 mm) above the unit's top edge. Air filters impede air circulation and require
a fan at inlet and/or outlet.
5.3

Installation Precautions

The following precautions are intended for use as guidelines for proper installation of the soft starter. Because of the
variety of applications, all of these precautions may not pertain to your system and they are not all-inclusive. In
addition to the following, refer to codes and standards applicable to your particular system.

5.3.1 Soft Starter Protection

When planning your installation, be aware of potential hazards to personnel and to the unit that can be caused by
control devices used in the system or by unique system features.
Motor Disconnect. When any motor disconnect device connected to the soft starter output (motor) terminals is
opened during operation, the soft starter continues to source full voltage if running. If the disconnect device is
reclosed, the motor will be restarted at full voltage. When the disconnect device is opened, a hazardous voltage is
present at the soft starter output terminals due to SCR and snubber leakage.
Motor Start/Stop. For normal operation, the soft starter is designed to start and stop the motor with signals that
are input to the soft starter's circuitry. Do not use the device that disconnects and reapplies line power to the soft
starter for ordinary starting and stopping of the motor.
8
cooling for the continuous power dissipation in the SCRs, approximately 3 watts per amp of continuous rating.
The following vent areas are required for each inlet and each outlet on customer furnished enclosures, motor
control centers, etc.
sq. in.
not required
20
40
80
120
Hazardous voltage.
Can cause death, serious injury,
or property damage.
To avoid electrical shock, this soft starter MUST be
wired with motor disconnecting means and branch
circuit protection because the soft starter does not
provide electrical isolation to the motor when the soft
starter is OFF.
Hazardous voltage.
Will cause death or serious injury.
To avoid electrical shock or burn, do not
touch soft starter terminals when voltage is
applied to the soft starter. Output terminals will
have voltage present even when soft starter is OFF.
2
cm A
not required up to 57 A
129 up to 131 A
258 up to 248 A
516 up to 480 A
774 up to 960 A
WARNING
DANGER
3ZX1012-0RW34-1AN1