On the working current of auxiliary contacts
2016-08-04
On the working current of auxiliary contacts
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As an auxiliary contact (or auxiliary switch) of the micro switch, it has two current parameters, one is the heating current, one is the working current. There are many kinds of working current, and the heating power is only one. The definition of the GB/T2900.18 heating supply current is: "under the conditions of the specified conditions, the switch electric appliances under the 8h operating system, the temperature rise of the parts can not exceed the maximum value of the maximum current carrying capacity." The operating current of the electromagnet is determined by the load function of the electromagnet which is controlled by the electromagnet in the closed state. So the heating current and operating current are two different concepts.
GN14048.5-93 "low voltage switchgear and control equipment control circuit devices and switching element of the first part of electromechanical control circuit devices" appendix C "some categories of auxiliary contact for nominal rating", list the action current currently used in AC-15 and DC-13, AC-15 categories, auxiliary contact Ith=2.5A, power control solenoid in the closed state (capacity) for 180VA; Ith=5A, Ith=10A, 360VA control power, control power of 720VA; DC-13 (DC) Ith=1A control, Ith=2.5A control, power 28W, power of 69W, Ith=5A, 138W Ith=10A, power control, power control for 275W. According to the electromagnet control power load, and the microswitch (auxiliary contact) voltage, it can calculate the working current, such as Ith=3A, power control can refer to Ith=2.5A, AC-15, control power is 180VA (in accordance with AC-15 provisions for AC magnet than 72VA load control), 180VA/380V=0.47A, 180VA/220V=0.81A. Is the auxiliary contact action current in 380V and Ie voltage of 220V; and DC-13 (control, Ith=2.5A, DC electromagnet) controlling the electromagnet capacity (power) for 69W, 69W/220V=0.31A, 69W/110V=0.63A, is the auxiliary contact working current in 220V and 110V, determine the working current of auxiliary contact is very important, because the auxiliary contact the electric performance test, non normal making and breaking capacity experiment and Ie numerical Ie for large or small are not Meet the requirements of the product.
Refer to the domestic market is still in the industry in 1997 accounted for a considerable proportion of MCCB and other two kinds of universal type breaker Revised Standard Version, that specified rated working current of auxiliary contact is very chaotic, does not conform to the national standard categories. For a circuit breaker, Ith, 3A, 6A, 1A, respectively. While working on the AC380V when the current Ie were 0.3A, 0.4A and 3A (both of them are the AC-15 category), power control AC electromagnet in the closed state, according to the calculation were 114VA, 152VA and 1140VA; in DC220V, Ie, 0.15A and 0.2A 0.15A respectively, then the power of DC electromagnet were 33W and 33W and 66W. Clearly does not meet the requirements of the GB14048.5 standard. The other two circuit breaker through regulation, AC electromagnet power 300VA, DC electromagnet power is 60W, this is the old standard of AC-11 and DC-11, but AC-11 and DC-11 in early 1993 to cancel the order, there is no reason to apply.
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As an auxiliary contact (or auxiliary switch) of the micro switch, it has two current parameters, one is the heating current, one is the working current. There are many kinds of working current, and the heating power is only one. The definition of the GB/T2900.18 heating supply current is: "under the conditions of the specified conditions, the switch electric appliances under the 8h operating system, the temperature rise of the parts can not exceed the maximum value of the maximum current carrying capacity." The operating current of the electromagnet is determined by the load function of the electromagnet which is controlled by the electromagnet in the closed state. So the heating current and operating current are two different concepts.
GN14048.5-93 "low voltage switchgear and control equipment control circuit devices and switching element of the first part of electromechanical control circuit devices" appendix C "some categories of auxiliary contact for nominal rating", list the action current currently used in AC-15 and DC-13, AC-15 categories, auxiliary contact Ith=2.5A, power control solenoid in the closed state (capacity) for 180VA; Ith=5A, Ith=10A, 360VA control power, control power of 720VA; DC-13 (DC) Ith=1A control, Ith=2.5A control, power 28W, power of 69W, Ith=5A, 138W Ith=10A, power control, power control for 275W. According to the electromagnet control power load, and the microswitch (auxiliary contact) voltage, it can calculate the working current, such as Ith=3A, power control can refer to Ith=2.5A, AC-15, control power is 180VA (in accordance with AC-15 provisions for AC magnet than 72VA load control), 180VA/380V=0.47A, 180VA/220V=0.81A. Is the auxiliary contact action current in 380V and Ie voltage of 220V; and DC-13 (control, Ith=2.5A, DC electromagnet) controlling the electromagnet capacity (power) for 69W, 69W/220V=0.31A, 69W/110V=0.63A, is the auxiliary contact working current in 220V and 110V, determine the working current of auxiliary contact is very important, because the auxiliary contact the electric performance test, non normal making and breaking capacity experiment and Ie numerical Ie for large or small are not Meet the requirements of the product.
Refer to the domestic market is still in the industry in 1997 accounted for a considerable proportion of MCCB and other two kinds of universal type breaker Revised Standard Version, that specified rated working current of auxiliary contact is very chaotic, does not conform to the national standard categories. For a circuit breaker, Ith, 3A, 6A, 1A, respectively. While working on the AC380V when the current Ie were 0.3A, 0.4A and 3A (both of them are the AC-15 category), power control AC electromagnet in the closed state, according to the calculation were 114VA, 152VA and 1140VA; in DC220V, Ie, 0.15A and 0.2A 0.15A respectively, then the power of DC electromagnet were 33W and 33W and 66W. Clearly does not meet the requirements of the GB14048.5 standard. The other two circuit breaker through regulation, AC electromagnet power 300VA, DC electromagnet power is 60W, this is the old standard of AC-11 and DC-11, but AC-11 and DC-11 in early 1993 to cancel the order, there is no reason to apply.
