Contactor technical parameters

1, rated voltage

(1) The rated voltage of the contactor nameplate refers to the rated voltage on the main contact. Commonly used voltage levels are: DC contactors: 110V, 220V, 440V, 660V and other grades. AC contactor: 127V, 220V, 380V, 500V and other grades. If a load is a 380V three-phase induction motor, a 380V AC contactor should be selected.

(2) Rated working voltage The rated working voltage is the voltage value that determines the contact condition of the contactor together with the rated working current. The technical parameters such as the contact and breaking capacity of the contactor, the type of working system and the type of use are all related to the rated voltage. For multiphase circuits, the rated voltage is the phase-to-phase voltage of the power supply (ie, the line voltage). In addition, the contactor can specify a number of sets of rated operating voltage and rated current according to different operating systems and usage categories. For example: CJ10-40 type AC contactor, the rated motor voltage is 220V, the motor can be controlled to 11kW, and the rated voltage is 380V, the motor can be controlled to 20kW.

(3) Rated insulation voltage The rated insulation voltage is a nominal voltage value related to the dielectric performance test, clearance and creepage distance. Unless otherwise specified, the rated insulation voltage is the maximum rated operating voltage of the contactor. In any case, the rated operating voltage must not exceed the rated insulation voltage.

2, rated current

(1) Rated current contactor Nameplate rated current refers to the rated current of the main contact. Commonly used current levels are: DC contactors: 25A, 40A, 60A, 100A, 250A, 400A, 600A. AC contactors: 5A, 10A, 20A, 40A, 60A, 100A, 150A, 250A, 400A, 600A. The above current means that the contactor is mounted on the open control panel, the contact does not exceed the rated temperature rise, and the load is intermittent - the current value during long-term operation. The so-called intermittent-long-term work system means that the contactor's continuous energization time does not exceed 8h. If it exceeds 8 hours, it must be opened and closed three times or more at no load to eliminate the surface oxide film. If the above conditions are changed, the current value is corrected accordingly. details as follows:

When the contactor is installed in the cabinet, the current is reduced by 10~20 due to poor cooling conditions;

When the contactor works in long-term work, and the power-on duration does not exceed 40; open installation, the current is allowed to increase by 10~25; the cabinet is installed, allowing 5~10 to be increased. Between these circumstances, may increase or decrease as appropriate.

2, rated working current

(1) The rated working current of the main contact is determined according to the rated working voltage, rated power, rated working system, type of use and protection type of the casing to ensure the normal working current of the contactor.

(2) Auxiliary contact rated working current The rated working current of the auxiliary contact is the current value of the auxiliary contact specified in consideration of the rated working voltage, the rated operating frequency, the type of use and the electrical life, and is generally not more than 5A.

(3) Use category The use category is defined according to the different characteristics of the different control objects of the contactor during operation. Contactors of different use categories have different requirements for switching on, breaking capacity and electrical life.