Aquasoft Series 2000 Starters

PRINCIPLES OF OPERATION

The Aquasoft is a low cost reduced voltage starter using semiconductor switching devices to control the voltage to the motor, automatically increasing the voltage from the preset start-up voltage point to full voltage.

CONTROLS

The 3 starting profile controls on the front cover are:

1)       A voltage pedestal (start volts) adjustable from 20 to 65% of the supply voltage.

2)       Acceleration ramp timer adjustable between 2-30 seconds.

3)       A current limit adjustment, operating between 2 to 4 times full load current.

STARTER SETTINGS

The pedestal volts should be set as low as possible, but must always allow the motor to begin rotation with the expected maximum load on the shaft.  The ramp time  should be set as short as possible while avoiding sudden acceleration and current surges.

The likely approximate settings would be in the region of 50% pedestal volts and 4 to 6 seconds acceleration time.  The motor current is a function of voltage and motor speed with sufficient voltage applied to allow the motor to accelerate.  Consequently depending on the shaft loading, the motor could accelerate to full speed before the set point of the ramp time.

However by adjusting the current limit lower than the maximum 4 times motor full load current the acceleration rate can be controlled.  This setting must not be “Too Low” or there will be insufficient acceleration torque and the motor will not reach full speed.

Ideally the current limit setting must be high enough not to hinder the break away of the motor which as previously noted is controlled by the pre-set pedestal voltage.  The pedestal (start) voltage should therefore be set first and high enough to obtain the break away required.  The current limit setting together with a suitable pedestal voltage and ramp-up time, will result in a smooth and well controlled start function.

The unit has no soft-stop facility but should this be required it is a standard feature in our Softronic soft starter series.

BY-PASS

The starter is fitted with a by-pass contactor which is energised by the top of ramp relay.  This parallel mains switching connects the motor directly to the 400V supply and the unit then runs as a normal direct-on-line starter.  As the contactor is not switching any load the current rating can be based on AC1 duty.

SAFETY TIMER

The unit is fitted with a safety timer set for a fixed 60 seconds which during normal operation will remove the control of the electronics from the supply.  If the top of ramp contactor does not close within the fixed time, the timer shuts the unit down.  Further protection is provided by an over temperature klixon fitted to the heatshink.

OVERLOAD AND UNDERLOAD

As a standard all Aquasoft starters are fitted with an Avanti PPR/3 pump protection relay.  This relay offers good overload and underload protection.  It must be set according to the instructions printed on the accompanied leaflet. Short form instructions are also printed on the side panels of the unit.

POWER FACTOR CORRECTION

Power factor capacitors may be used, but must be connected via a contactor to the supply side of the unit and not to the motor terminals.

Aquasoft Modules "Thyristor Stack with Card" -  Specifications

Voltage:

400 volt 50Hz

Current

Ratings:

For use with by-pass contactors

3.5 times F.L.C. for 12 seconds max.

Card Control

- voltage:

20 volts A.C. (loose transformer) 400

230/20V 10VA

Control

Terminals:

Stop 2 terminals (20VAC)

Start 2 terminals (20VAC)

Top of ramp 6 terminals D.P.C.O.

Run relay 3 terminals S.P.C.O.

Voltage free

Relay rating: 

5 Amps maximum

400 volt maximum

Starting

Profile:

Pedestal level (start volts)

Adjustable 20 to 65%

Acceleration ramp

Adjustable 2 to 30 seconds

Current limit 2-4 times motor full load current.

Starting duty:

6 starts per hour

1 start every 10 minutes

Indicators:

Power on

Start

Top of ramp

Current limit

- Red L.E.D.

- Red L.E.D.

- Green L.E.D.

- Green L.E.D.

Sizes available: 

11/15KW

18.5KW      

22/30KW   

37KW

45/55KW

by-pass contactors

must be fitted to all units