ABB PSR12-600-70 Compact Soft Starter, 12 A

In ABB’s PSR compact range, which covers 3 to 105 A at 208 to 600 V AC, the PSR12-600-70 (1SFA896106R7000) is the 12 A model. A voltage ramp replaces the abrupt across-the-line start, giving the driven machine a gradual torque build-up and a soft stop. The built-in bypass closes after the ramp, so continuous running produces little heat, and only two phases are controlled. It is intended for 5.5 kW class motors on pumps, ventilation fans and light conveyors, within the pump, fan, compressor and conveyor duties ABB describes.

More starters are shown under motor soft starters; for a larger motor see the PSR30-600-70 page.

Technical specifications

Starts per hour, temperature and altitude for the PSR12

Start from the motor current on the nameplate: 12 A is the ceiling of this model, and ABB sizes duty by current rather than by kW. Under ABB’s reference conditions of 40 C, 4 x Ie and a 6 second ramp the PSR12 allows 10 starts per hour as supplied, rising to 20 with the optional fan; the figures assume 50 percent on-time. Above 40 C and up to 60 C the rated current falls by 0.8 percent per degree. Altitude derating starts at 1000 m, using 100 minus (x minus 1000) over 150 percent, with a ceiling of 4000 m. Heavier starting duty is outside these tables; use ABB’s selection tool or the next frame.

In the catalogue the PSR12 is paired with the MS132 manual motor starter, 32 A gG fuses (50 kA), a 35 A J-type fuse for UL, an overload relay of type TF42 and a line contactor of type AF12. The line contactor is not needed by the softstarter itself, but it is often used to open the circuit if the overload relay trips. Kits for direct connection to ABB manual motor starters are available, as is the PS-FBPA fieldbus plug adapter. Other short-circuit protection devices can be checked in ABB’s online coordination tool.

Mounting, indicators and settings

It is built in the PSR3 to PSR16 frame: IP20 main circuit and control circuit, 12 VA at 100-240 V AC, DIN rail or screw fixing. Three front potentiometers set start ramp time, stop ramp time and initial or end voltage, and LEDs show On/Ready and Run. The narrow housing lets several starters share one enclosure. Leave the clearances given in the manual for cooling.

Nearby types in the 100-240 V AC range

Adjacent sizes of the -70 range are below; pick the one that matches the motor current.

Why choose a soft starter for a 5.5 kW motor

Starting a motor directly on line draws several times the rated current and applies full torque instantly. On pumps this can cause water hammer in the pipework; on belt conveyors it can make belts slip or products fall over; on fans it stresses couplings and belts. The PSR12-600-70 ramps the voltage up over 1 to 20 s, which reduces the current peak and the mechanical shock, and its stop ramp of up to 20 s lets pumps slow down gradually to reduce pressure surges when stopping. Unlike a frequency inverter, a soft starter does not control speed during running; once the bypass closes, the motor runs at full speed directly from the supply. For fixed-speed duty this keeps the solution compact and simple.

Key features of the PSR12

• Two-phase control with an integrated bypass, giving the low 11.5 W maximum power loss at 12 A.
• Three potentiometers for start ramp, stop ramp and initial/end voltage – no software needed.
• Wide main voltage range of 208 to 600 V, so one type covers 400 V and many other networks.
• 100–240 V AC control supply for panels without a 24 V system.
• Compact 0.4 kg unit for DIN rail or screw mounting.

Setting up for a smooth start

1. Start with a moderate initial voltage and a ramp of a few seconds, then adjust while watching the load.
2. If the motor hums but does not turn at the beginning of the ramp, raise the initial voltage.
3. For centrifugal pumps, use the stop ramp to limit water hammer; for fans, a stop ramp is often unnecessary.
4. Remember that the PSR has no integral motor overload protection, so an overload relay or manual motor starter must be part of the circuit, as shown in ABB’s coordination tables.

Heat and dust in Gulf panels

The rated current applies up to 40 °C ambient, and Oman’s summer cabinet temperatures often exceed this. Apply the 0.8 percent per degree derating above 40 °C, and consider the optional fan where starts per hour are high. As an IP20 device it must be installed in an enclosure that keeps sand, dust and moisture out. Typical uses in the region include water transfer and booster pumps, cooling tower and ventilation fans, and small conveyors in mining and cement plants.

RFQ details

Include the type PSR12-600-70 and order code 1SFA896106R7000, the motor nameplate current, mains and control voltages, expected starts per hour, ambient temperature, and any fan, connection kit or fieldbus adapter required.

Type code, order check and documents

The PSR12-600-70 code reads: PSR family, size 12, 600 V class, -70 for a 100-240 V AC control supply (the 24 V AC/DC type ends -11). Please confirm the motor current, supply voltage, control voltage, starts per hour and any connection kit or fan before ordering.

Attached is the PSR chapter extracted from ABB’s softstarter catalog 1SFC132012C0201, including order data, technical data and circuit diagrams. Seven Star LLC (independent supplier, Muscat) quotes on request; prices and stock are not displayed here.