Lovato ADXT0139 139 A Soft Starter

ADXT soft starter rated 139 A for three-phase motors

In the Lovato Electric ADXT range the ADXT0139 is the 139 A size for standard and heavy-duty starting. Its bypass is integrated, the power side works on 380-690VAC and the electronics are fed separately from 110-120VAC / 220-240VAC.

The ADXT0139 controls 3 phases of the motor circuit and limits the inrush through constant current, current ramp, voltage ramp, adaptive control. In the catalogue it is rated 139 A, which Lovato translates into 75 kW at 400 V in line and 110 kW at 400 V when connected inside the delta of the motor winding.

Technical specifications

How to match the rating to the motor

Start from the full-load current on the nameplate. With a rated starter current of 139 A, this unit covers motors up to 75 kW at 400 V when wired in line; the datasheet applies a current derating when the ambient passes 40 degC (operating maximum +60°C (with current derating >40°C)).

Order-code reading, derived from the catalogue entry: the characters after ADXT give the current size (139 A for this code), with the standard auxiliary-supply version covering 110-120VAC / 220-240VAC.

Installation and typical duties

Typical jobs are centrifugal pumps, fans, compressors and conveyors where a ramped start protects couplings, belts and pipework. On a water or wastewater line the stop ramp softens the pressure surge when the motor is switched off, and the adjustable current limit helps on weak or generator-fed supplies.

Physical data: 216x495x244 mm, 12.7 Kg, IP00. The starter has 4 digital inputs and 3 digital outputs, enough for start, stop, reset and a line-contactor command without an interface relay.

In-line or inside-delta connection

The ADXT0139 can be wired in two ways, and the choice changes the motor power it can handle. In the in-line connection the starter sits between the supply and the motor terminals and carries the full line current; three motor cables are needed. In the inside-delta connection the starter is placed inside the delta of a six-terminal motor, so each starter phase carries only the winding current, roughly 58 percent of the line current. That is why the same 139 A unit is listed at 110 kW at 400 V inside delta instead of 75 kW in line. Inside delta requires a motor with six accessible terminals suitable for delta running and six motor cables, and the wiring must follow the manufacturer’s diagram exactly.

Choosing the start and stop method

• Constant current: the most common setting, limiting the starting current to a fixed multiple of motor current until the motor reaches speed.
• Current or voltage ramp: useful where the supply is weak or generator-fed and the load should come up gradually.
• Adaptive control: shapes the acceleration or deceleration profile to the load, and is particularly helpful on pumps to reduce water hammer when stopping.
• DC braking or soft stop with braking contactor: shortens the stopping time on high-inertia loads such as fans and saws, where free-wheeling would take too long.

Installation and maintenance practice

• Because the unit is IP00, install it inside an enclosure that protects personnel from live parts and keeps dust out.
• Allow ventilation clearance and check the panel temperature: above 40 °C the current must be derated.
• Use the line-contactor output so that the main contactor opens on a trip.
• Connect the motor thermistor to the PTC input where the motor has one, for direct winding temperature protection.
• Review the fault log periodically; repeated “starting too long” or locked-rotor events usually point to a mechanical problem on the driven equipment.

Use in Oman and GCC conditions

Panels in GCC substations and pump houses often run well above 40 °C internally in summer. The ADXT0139 operates up to +60 °C with derating, so either size the starter for the derated current or cool the panel. The integrated bypass removes most of the thyristor heat during running, which helps in these conditions. Typical local uses are irrigation and water transfer pumps, chiller and cooling tower fans, and compressors in industrial plants.

What to include in your RFQ

• Motor power, full-load current and supply voltage
• In-line or inside-delta connection
• Load type, starts per hour and required starting time
• Auxiliary control voltage and maximum panel temperature
• Quantity required

Documents and quotation

The Lovato Electric datasheet for ADXT0139 (English, exported from the manufacturer’s online catalogue) is attached and is the source of the figures above. Check the motor nameplate current and starting duty, the main supply voltage, the auxiliary control voltage and the ambient temperature at the panel against your own drawings first; the manufacturer may update datasheet figures without notice. More products of this type are under motor soft starters. Use the quotation form with the code ADXT0139 and your quantity; availability is confirmed by Seven Star LLC, an independent supplier in Muscat.