Soft starter mounting

In soft starter, the thyristors and microprocessors are used that can cause emission during operation. This emission can be reduced by using a by-pass contactor that ensures the system fulfills the compatibility requirement. Another advantage by using a by -pass contactor is that the total power loss is reduced, and thus it is not needed to have extra fans for cooling if the soft starter is enclosed.

Bypass contactor: When a by-pass contactor is used, the soft starter is by-passed at continues operation, the bypass contactor is connected in parallel to the softstarter that is only active during start and stop of the motor. The operation is simplified if the built in signal relay K5 (top of ramp/TOR) is used to control the by-pass contactor. The bypass contactor is automatically in operation after completed start and will remain during continuous operation. The soft starter can still be in active status but no current will pass through it, instead all current will pass through the by-pass contactor for connection of the by-pass contactor.

Function PF (Energy saving at low motor load): Cannot be activated during operation with a by-pass contactor included.
Earthing: The soft starter has to be connected to earth for safety.

Semiconductor fuses: The semiconductor fuses are not delivered built in the starter unit. Use the recommended fuses given in the technical data. The combination fuse size and soft stater allows the maximum use of starting time and current given for each soft starter without tripping.

Overload relays: The relay will protect both the motor and the soft starter from over-heating during start and continuous run.

Mounting: The soft starter must be mounted so that the cooling air passes vertically over the heat sink. It must also be placed so that the cooling capacity is not decreased due to pollution or similar.

Open type soft starters are to be mounted in a cubicle or other enclosure. Hole configuration according to information given on the dimension prints. For installations (how to wiring?) there is a need to ventilate enclosure when a "sealed" enclosure is requested and when not using a by-pass contactor, the size must be such that the heat generated by the thyristors can be carried off from the enclosure surface without the enclosures' inside temperature becoming too high.

Ventilated enclosures can be considerably smaller. The size depends entirely on the ventilation and must be determined for each individual case.