Albright International Coil Ratings Terminology

Wednesday, 26 July 2017  |  AdrianR

Albright coils in their contactors are wound with Pull-in and Drop-out voltages, variations of those features can be engineered to suit particular applications. You can use this blog post in conjunction with the Arc Components Ltd Product Files to identify a solenoid contactor best suited for your application.

Operating Coils

 Coil voltages ranging from 6 to 240V are available, which are wound for D.C. operation. However, the majority of coils can be factory fitted (via an enquiry) with a bridge rectifier for use with A.C. supplies. Coils are wound with Pull-in voltages (coils at 20°C) of approximately 66% of the rated voltage (Continuous) or 60% (Prolonged, Intermittent Or Very Intermittent), and Drop-out voltage nominally greater than 10% of the rated voltage. Variations of these Pull-in and Drop-out figures can be engineered to suit particular applications.


Continuous (CO)

 100% duty cycle. Continuous operation. The weakest power coil dictates that a weaker return spring is used compared to the intermittent equivalent. This does not give the best switching characteristics for applications frequently switching on load.

Prolonged (PO)

 Up to 90% duty cycle, up to 54 minutes continuous energisation. The coil is more powerful than continuous and weaker than intermittent equivalent. The return spring is stronger than continuous but weaker than intermittent.

Intermittent (INT)

 Up to 70% duty cycle, up to 15 minutes continuous energisation. High power in the coil allows a strong return spring to be used, giving good switching characteristics. Typically this rating is used with magnetic latching contactors.

Highly Intermittent (HO)

 Up to 25% duty cycle, up to 3 minutes continuous energisation. The highest power in the coil allows the strongest return spring to be used, giving good switching characteristics.




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