Lovato SM1P0250 Motor Protection Circuit Breaker 1.6-2.5 A

Lovato SM1P0250 motor protection circuit breaker, 1.6 to 2.5 A

The Lovato SM1P0250 is a three-pole manual motor starter and protector with a thermal setting range of 1.6 to 2.5 A. It combines overload, short-circuit and phase-loss protection in one DIN-rail body, so a small motor can be isolated, started by hand and protected without a separate fuse and thermal relay. Seven Star LLC supplies the SM1P0250 in Oman and the GCC as an independent supplier in Muscat.

Reading the code is simple: SM1P is the family with a rotary push-button style front, and 0250 means a rated current of 2.5 A, the top end of the band. The family steps upward in fixed ranges, so the SM1P0160 covers 1 to 1.6 A and the SM1P0400 begins at 2.5 A. A motor with a nameplate current of 2 A sits comfortably in the middle of this range, where the dial has room to adjust in both directions.

SM1P0250 technical specifications

How the SM1P0250 trips

The thermal release is a bimetal system heated by the motor current. On a gradual overload it bends until the mechanism trips, following a class 10A curve that allows a normal start of a few seconds but disconnects a stalled or jammed motor. Because the device has phase-failure detection, the release also responds faster if one conductor drops out, a condition that otherwise overheats the remaining two windings.

The magnetic release is fixed at 13 times the rated current. At the 2.5 A rating that is a threshold of about 32 A, which is well above a typical starting inrush for small motors and still low enough to open quickly on a cable or winding fault. Set the thermal dial to the nameplate current, not above it, and the combination gives accurate protection across the whole band.

Breaking capacity of the SM1P0250

A strong point of this low-current member of the range is its breaking capacity: 100 kA from 230 V up to 500 V for both Icu and Ics. Only at 690 V does it fall to 3 kA. Panels placed close to large transformers, as in many process plants, can therefore use it without an extra back-up device, although the voltage rating of the installation should always be checked against the table above.

The UL data adds a 30 kA rating at 240, 480 and 600 V for motor-disconnect and group-installation use with a 100 A class J fuse, and maximum horsepower values of 1/2 HP at 200 to 240 V and 1 HP at 440 to 480 V three-phase. These figures apply only where the project requires UL-style documentation.

SM1P0250 in a motor starter

Used alone, the breaker is a manual starter. Used with a small contactor from the same maker, such as a BF09 series part like the BF0910A230, it becomes a remote-controlled combination starter in which the breaker protects and the contactor switches. For group installations several SM1P breakers can feed from a common busbar, keeping panel wiring compact. Neighbouring ratings include the SM1P0160, the SM1P0400 and the SM1P0650.

SM1P0250 selection and ordering checklist

• Nameplate current between 1.6 and 2.5 A at the supply voltage
• Starting time and load type, to confirm class 10A is suitable
• System voltage, since the breaking capacity changes at 690 V
• Prospective fault current at the installation point
• Whether manual operation only or a combination with a contactor is needed
• Panel temperature and the compensation limit of 50 °C
• Whether UL horsepower ratings are required by the project

Installing and maintaining the SM1P0250

Fit the breaker on a 35 mm rail or with screws in any orientation within the permitted plane, strip 10 mm of conductor and tighten the power terminals to 2.5 to 3 Nm with a PH2 driver. Dial the setting to the motor nameplate value and test the handle before energising. IP20 on the front means the unit belongs in a closed enclosure.

During routine inspection, look for discolouration at terminals, run the handle a few times and compare real motor current with the setting using a clamp meter. After a trip caused by a short circuit, check the load and cable before resetting, and replace the breaker if the housing is damaged.

Typical SM1P0250 applications in Oman and the GCC

A 2.5 A setting is common on chemical dosing pumps, small circulation pumps, ventilation fans in switch rooms and compact conveyors. In Gulf plants the heat inside panels is the main concern; at ambient temperatures above 50 °C inside the cabinet the thermal curve is no longer compensated, so ventilation or filter maintenance matters as much as the breaker choice.

SM1P0250 neighbouring ratings

Information to send with an RFQ for the SM1P0250

• Part number SM1P0250 and quantity
• Motor nameplate current and voltage
• Prospective short-circuit current
• Downstream contactor, if any
• Enclosure ambient temperature
• Any marking or approval requirement

Documents and quotation

Send the part number SM1P0250 and we will confirm the documents available for it, such as the technical data sheet, wiring diagram and instruction sheet, together with availability and lead time.

Seven Star LLC is an independent supplier in Muscat and is not an official channel of the manufacturer. Share the quantity, delivery location and project reference with the request and we will answer with a formal quotation.