ABB AF Contactors

AF contactors are used in motor starters and power-switching assemblies. ABB offers 3-pole AF contactors for motor starting and 4-pole versions for power switching. The exact main-contact arrangement, auxiliary contacts and ratings depend on the complete designation. Pumps, compressors and ventilation equipment are examples of motor-control applications; heaters and other loads require their own duty assessment.

Electronic Coil & Control Supply

AF technology uses an electronically controlled coil: its electronics convert the specified AC or DC control supply for coil operation. ABB documents a wide operating-voltage band, reduced coil consumption and built-in surge suppression for this technology. This helps manage control-supply variation, but is not permission to operate outside the selected coil’s limits.

Check the full coil suffix, voltage band, AC/DC suitability and frequency in the product data. Do not assume a particular control-voltage range fits every AF frame or old reference. Confirm pickup/holding requirements and control-output capability for PLC operation, especially where a dedicated interface version is required.

AF, AFC & AFS References

• AF: ABB’s electronically controlled contactor family, with separate 3-pole motor-control and 4-pole power-switching offerings.
• AFC: ABB identifies a related family for AC control circuits using conventional contactor technology. Do not apply AF AC/DC electronic-coil characteristics to an AFC reference.
• AFS: contactors intended for machine-safety applications, with factory-mounted mechanically linked and mirror auxiliary contacts for feedback monitoring. A complete safety function still requires system design and validation; an AFS designation alone does not establish a system safety level.

Load Duty, Ratings & Standards

AC-1 covers non-inductive or slightly inductive loads, such as resistance heating. AC-3 covers starting squirrel-cage motors and switching them off while running. An AC-1 current is not the AC-3 motor current, and a motor kW rating must be read at its stated voltage. Inching, plugging, frequent reversing or high starting current require a separate duty check rather than selection by AC-3 power alone.

ABB’s AF contactor guide uses IEC/EN 60947-4-1 ratings. UL/CSA motor horsepower and general-use ratings are separate selections at their stated voltages; do not convert them into an IEC rating or assume all regional approvals cover every reference. DC loads, lighting and capacitor switching also require the appropriate application data.

Confirming a Specific Contactor

Provide load type, supply voltage/frequency, motor nameplate current and power where applicable, utilization category, switching frequency and starting duty. Confirm the control supply, main poles/contact arrangement, required NO/NC auxiliary contacts, terminal type, mounting space and ambient conditions. For a starter, check the overload relay, short-circuit protection and ABB coordination data as an assembly; the contactor itself is not an overload or short-circuit protective device.

Related pages: Contactors & Motor Starters and Contact.

ABB references: AF electronic-coil technology; Contactor guide and load categories; 4-pole AF; AFC AC-control family; AFS safety applications.