Lovato BFS0923A024 Contactor

BFS09 safety contactor with mechanically linked contacts: rated currents and coil data

The BFS0923A024 is a safety contactor with mechanically linked contacts from the Lovato Electric BFS09 series. Its AC-3 operating current is 9 A, equal to 4.2 kW at 400 V and 2.2 kW at 230 V for a standard squirrel-cage motor. The coil is rated 24 V, and the insulation voltage Ui is 690 V.

Mechanical life is 20,000,000 cycles, the free-air thermal current is 25 A and the unit weighs 360 g.

Technical specifications

Reading the ratings

Decide the load type before the size. Motor loads are rated by AC-3, heaters by AC-1, and plugging or jogging duty by AC-4; the datasheet lists a current for each category, and the lowest applicable one governs.

Order-code reading, derived from the catalogue entry: BFS0923 identifies the contactor size and auxiliary-contact arrangement, and the last characters give the coil voltage (24 V).

The BFS design has mechanically linked contacts, so a welded main contact is signalled by the auxiliary set; the safety-circuit design (category, Performance Level) remains the responsibility of the machine builder.

Using it in a starter

The usual arrangement is breaker or motor protection circuit breaker upstream, contactor in the middle, thermal or electronic overload relay downstream. Control by PLC output needs the coil voltage to match the output supply.

At 360 g the contactor is easily handled in a panel; fixing is screw or DIN rail, and the allowable mounting angle and operating temperature are in the table.

Why mechanically linked contacts matter in safety circuits

In a machine safety function, the control system must be able to detect whether a contactor has actually opened when it was commanded to. If a main contact welds closed, the motor could continue to run or restart unexpectedly even though the safety device has demanded a stop. With mechanically linked contacts, the auxiliary contacts are tied to the main contacts so that they cannot indicate an open state while a main contact remains closed. Feeding the auxiliary contact back into the safety relay or safety controller as a monitoring signal lets the system detect this fault and prevent a restart.

This is why contactors such as the BFS09 are often found in circuits with emergency stops, guard interlocks and light curtains on machinery. As noted above, the overall category and Performance Level depend on the full circuit design and remain the responsibility of the machine builder, who should follow the relevant machinery safety standards.

Selection considerations

Start with the load: confirm the motor or heater current and choose the utilisation category that matches the duty. For motors with frequent inching, plugging or reversing, the AC-4 value is the relevant one. Check the ambient temperature inside the panel against the derating steps in the AC-1 rows, since panels in warm plant rooms can run well above the outside air temperature. Then confirm the coil voltage and supply type against the control circuit, and check that the auxiliary contact arrangement of this order code suits the monitoring scheme of the safety circuit.

Where two contactors are used in series for redundancy, as is common in higher safety categories, both are usually chosen from the same series so that their behaviour and feedback contacts are consistent.

Installation practice in general terms

Mount the contactor in the normal vertical position or within the allowable angle given in the table, on a DIN rail or with screws. Tighten terminals to the values in the Lovato instructions and respect the number of conductors per terminal. Keep power and control wiring separated where practical, and label the feedback circuit clearly so that it is not bypassed during later maintenance. After installation, the safety function should be tested and the result recorded as part of the machine validation.

Panel conditions in Oman and the GCC

Control panels in the region are frequently installed in hot, dusty locations such as pump stations, workshops and outdoor skids. The temperature-related ratings in the table should be checked against the expected internal panel temperature, not only the room temperature, and the panel enclosure should limit dust ingress according to the pollution degree assumed for the installation. Periodic functional testing of the safety circuit, including the feedback from the linked contacts, helps confirm that the protection remains effective over the life of the machine.

Documents and quotation

All data on this page for BFS0923A024 is taken from the Lovato Electric catalogue datasheet (English), which you can download from the attachment list. Before ordering, confirm the motor current, coil voltage, the number and type of auxiliary contacts and the utilisation category of your load; datasheet values can be revised by the manufacturer. For related parts browse contactors & overload relays. Send the order code BFS0923A024, the quantity and the delivery location through the quotation form and Seven Star LLC, an independent supplier in Muscat, will reply with availability.