What is the maximum operating temperature of the handcart circuit breaker contact? 5

According to the national standard for circuit breakers GB1984-2003 and the technical standard for high-voltage equipment sharing GB T 11022-1999 for the definition of the maximum operating temperature of circuit breaker contacts: the ambient air temperature does not exceed 40, and does not exceed the following temperature values.

When the contact is made of bare copper or bare copper alloy:

Not more than 35 in air, i.e. no more than 75 in maximum temperature — no more than 65 in SF6 (sulfur hexafluoride), i.e. no more than 105 — no more than 40 in oil, i.e. no more than 80 when the surface of the contact is silver-plated or nickel-plated:

No more than 65 in air, that is, the maximum temperature does not exceed 105 - in SF6 (sulfur hexafluoride) does not exceed 65, that is, the maximum temperature does not exceed 105 - in oil does not exceed 50, that is, the maximum temperature does not exceed 90 When the contact surface is tinned:

Not more than 50 in the air, i.e. the maximum temperature does not exceed 90 - in SF6 (sulphur hexafluoride) does not exceed 50, that is, the maximum temperature does not exceed 90 - in oil does not exceed 50, that is, the maximum temperature does not exceed 90

The maximum operating ambient temperature is 40 degrees, and the temperature rise does not exceed 65K for long-term operation. Maximum operating temperature: 40+65=105 degrees.

60 to 80 degrees or so is no problem, and the damage at high is very fast.

The ambient temperature is -25-40.

The circuit breaker can be used to distribute electric energy, start the asynchronous motor infrequently, protect the power supply line and the motor, and automatically cut off the circuit when they have serious overload or short circuit and undervoltage and other faults, and its function is equivalent to the combination of fuse switch and over/underheat relay. In addition, it is generally not necessary to change the parts after the fault current is switched off. At present, it has been widely used.

Main features: The main characteristics of the circuit breaker are: rated voltage UE; Rated current in; Trip current setting range for overload protection (IR or IRTH) and short-circuit protection (IM); Rated short-circuit breaking current (ICU; household circuit breaker ICN) and so on.

Rated Operating Voltage (UE): This is the voltage at which the circuit breaker operates under normal (uninterrupted) conditions.

Current Rating (in): This is the maximum current that a circuit breaker equipped with a special overcurrent trip relay can withstand infinitely at the ambient temperature specified by the manufacturer, and will not exceed the temperature limit specified by the current acceptance component.

The general requirement is that the ambient temperature is -25 40. The temperature rise value varies slightly depending on the surface treatment of the conductor and the connection method.

The specific allowable value of temperature rise can be checked according to the standard. Generally, it is 60, 65, and 75k.

Above 4000A, it is generally necessary to force air cooling, and the larger the current, the greater the contact temperature

The contact temperature of ABB vacuum circuit breaker is the same as that of Zhejiang Xuli vacuum circuit breaker VS1, and the maximum allowable temperature is not more than 35 degrees.

It depends on the temperature rise, which is the temperature minus the ambient temperature.

In the case of ordinary miniature circuit breakers, the temperature rise of the stable rear terminal cannot exceed 60K, assuming that the ambient temperature is 25 degrees, then it cannot exceed 85 degrees.

In addition, if the handle is metal, it is no more than 25k, the touched surface is 40k, and the difficult to reach is 60k.

If you don't understand, you can ask, I hope it can help you.

This doesn't necessarily come to be. You can't be a single source.

Consider the convection of air alone.

There are many factors that affect the temperature, and theoretically it is the temperature of phase b above.

The degree is the highest, and this is because the hot air runs upwards.

Your situation is probably due to the proximity of phase B to the conductive clamp in the circuit breaker, and the temperature is transferred to the contact under phase B due to heat conduction.

In addition, the difference in the compression force of the plum blossom contact spring and the reduction of the contact area caused by the eccentricity of the contact, the tightness of the bolt fixation, and even the unevenness of the coating will affect the increase of temperature.

The upper contact, theoretically, the order is lower A, C is the lowest, upper A, C is slightly higher, followed by the lower B phase, and the upper B phase.

This is because the hot air runs upwards, and the B phase in the middle has less space for heat dissipation than on both sides.

Phase B above.

The heat dissipation conditions are the worst.

I have some experimental data that I can provide if needed.

In general, the maximum temperature of the switch contacts of the high-voltage switchgear should not exceed 75.

Because the switchgear often uses polymer insulation materials, the aging of polymers will become faster at high temperatures, and the restriction of this temperature is for safety reasons, but there is no national standard for this temperature now, and the standard I use is not more than 70 degrees, and the contacts will be overhauled if they exceed 70 degrees.

Temperature at the connection of the control cabinet.

Switch contact push-to-connect considerations.

Bus bars and cable joints are considered according to static connection.

The maximum temperature of the dynamic connection should not exceed 70

The maximum temperature of the static connection should not exceed 75

The allowable temperature of the switch contact, this may not be uniformly regulated, personal understanding, as long as it does not affect the mechanical strength, there is no problem without melting, not more than 250 degrees. (FYI).

With the increase of the flow time, the temperature increases, the silver plating layer is further oxidized, the resistance is further increased, and the temperature continues to rise.

If the occlusal depth is not enough and the occlusal contact surface is too small, there is a short-circuit current, and the electrodynamic force generated will cause the plum blossom contact to separate the static contact, resulting in an open circuit.