The SS6312 Soft Starter is designed for single-phase air conditioning compressor motors in the range of 2 – 6 HP. It is a Master controller in that it replaces the compressor contactor. It can also operate as a Slave controller from the compressor contactor. If the Soft Starter is supplied with a 6 wire connection, then connect the Start (Grey) cable with the Active (Brown) cable. The Run Cap (Orange) cable is not used and must be terminated or insulated. However a 4 wire cable loom can be supplied for Slave applications. The cable loom connection to the Soft Starter is an 8 way RAST5 connector. The RAST5 connector is a DIN Standard rated at 16A, which is de-rated from the nominal 20A for 6.35mm connectors. The Active and Run Winding cables are duplicated to increase their current capacity to 32A.
Under starting conditions, the soft starter will switch in a starting capacitor and reduce the supply voltage to the motor. The supply voltage will ramp the motor up to full speed after which a relay will operate and bypass the SCR’s. This is not a linear ramp, but a complex algorithm designed to achieve minimum starting currents. The soft starter is auto sensing so that on start up, it will determine what size motor is connected and will select the appropriate starting curve for that motor. The motor will be ramped to full speed in approximately 0.75 second. For motors that require faster starting times due to onboard system diagnostics, then special starting curves that accelerate the motor to full speed in less than 0.5 second are available. This does result in increased currents. Custom manufacturer starting curves are accommodated with a 16 position rotary or 3 position dip switch. Typical starting currents for 3, 4, 5 & 6 HP motors are 26A, 32A, 38A & 39A.
There are two LED’s on the front panel, amber and red. The amber LED indicates power on, if it is fl ashing then it is attempting a restart. If the motor does not start, the soft starter will detect this, wait 3 minutes and attempt a restart. It will attempt two restarts. If it fails a second restart, it will shut down and fl ash a fault code on the red LED. The soft starter also has a data logger. It will store data on the last 10 starts.
Sometimes new Scroll compressors draw excess current when started initially. This could result in the Soft Starter detecting an over current and going into restart mode. Wait 3 minutes and it should start.