Dual power supply knowledge

• Contact switching time:

Measure the time from the time the first set of main contacts disconnects the normal power supply to the time the second set of main contacts closes the standby power supply.

• Conversion action time:

The time from the moment the deviation of the main power supply is detected to the moment the main contacts close the backup power supply is measured, excluding the delay introduced.

• Total action time:

The sum of the conversion action time and the intentionally introduced delay.

• Returns the conversion time.

The time from the moment the normal power supply fully returns to normal to the moment the main head group closes the normal power supply plus the intentionally introduced delay.

• Power off time:

The time measured from the moment the arc of each phase is finally extinguished to the moment the main contacts close during the transfer process of another power supply under the condition that the longest arcing duration occurs.

Description of electrical grade

——PC level: TSE that can connect and carry, but not be used to disconnect short-circuit current:

Note: If the test requirements of PC level can be met, the contactor can be used for PC level.

——CB level: TSE equipped with an overcurrent release, whose main contacts can be connected and used to disconnect short-circuit current.

——CC level: TSE that can connect and carry, but not be used to disconnect short-circuit current. This TSE mainly meets

The electrical components required by GB 14048.4.

Description of usage category

AC——33iB The total system load includes cage motor and resistive load.

AC - 33B Motor load or a mixed load consisting of a motor, a resistive load and less than 30% incandescent lamp load.

MTSE is a manually operated transfer switch appliance; manually operated transfer switch appliance.

RTSE Remotely operated transfer switching electrical appliance; Remotely operated transfer switching electrical appliance.

ATSE Self-acting transfer switching device; Automatic transfer switching device.

Breaking capacity

The expected breaking current value that a switch or fuse can break at a specified voltage under specified conditions of use and performance.

Connection capability

Under specified conditions of use and performance, the expected make-before current value that the switching device can connect at a specified voltage.

Short circuit breaking capacity

The breaking capacity under specified conditions, including short circuit of the switching device terminals.

Short circuit connection capability

The connection capacity under specified conditions, including short circuit of the terminals of the switching device.

Break time:

The time interval from the moment of disconnection of the mechanical switch (or the pre-arcing time of the fuse) to the moment of the end of the arcing time

Connection time

The time interval from the moment the mechanical switch is closed to the moment the current starts to flow through the main circuit.

Closing time

The time interval from the moment the switching device starts closing to the moment the contacts of all poles are in contact.

On-off time

For a release that is powered on and disconnected at the moment the current starts to flow in the main circuit, it refers to the time interval from the moment the current starts to flow through one pole of the switching device to the moment the arc is finally extinguished in all poles.

Electrical clearance

The shortest straight-line distance between two conductive parts.

Electrical gap between poles

The electrical clearance between any conductive parts between adjacent poles.

Electrical clearance to ground

The electrical clearance between any conductive part and any part which is earthed or used as earth.

Electrical gap between disconnected contacts (opening distance)

The total electrical clearance between the contacts of one pole of a mechanical switching device or any conductive parts connected to the contacts when in the off position.

Isolation distance (of one pole of a mechanical switch)

The electrical clearance between contacts in the open position when the specified isolator safety requirements are met.

Creepage distance

The shortest distance between two conductive parts along the surface of the insulating material

Operating voltage

The highest effective value of AC voltage or the highest value of DC voltage that may occur (locally) at any insulation end at the rated supply voltage.

Switching overvoltage

A transient overvoltage that occurs at a certain location in the system due to specific switching operations or faults.

Lightning overvoltage

A transient overvoltage that occurs at a certain location in a system due to a specific lightning discharge.

Impact pressure resistance

The highest peak value of impulse voltage with a certain shape and polarity that does not cause breakdown under specified test conditions.

Power frequency withstand voltage

The effective value of the power frequency sinusoidal voltage that does not cause breakdown under specified test conditions.

breaker

A mechanical switch that can connect, carry and disconnect current under normal circuit conditions, and can also connect, carry for a certain time and disconnect current under specified abnormal circuit conditions (such as short circuit).

Frame grade

A term used to indicate the characteristics of a group of circuit breakers whose structural dimensions are the same for several current ratings. The frame class is represented by the maximum value A corresponding to this group of current ratings. Within a frame class, the width may vary with the number of poles.

Structure segment

- Significant differences in construction between circuit breakers of a given frame size require additional type testing

Circuit breaker with fuse

A single electrical appliance composed of a circuit breaker and a fuse, each phase of which consists of a fuse connected in series with one pole of the circuit breaker.

Current limiting circuit breaker

A circuit breaker whose breaking time is short enough to prevent the short-circuit current from breaking before it reaches its expected peak value (which it would otherwise reach).

Plug-in circuit breaker

In addition to the disconnect contacts, the circuit breaker also has a set of detachable contacts, which allows the circuit breaker to be pulled out or inserted into the circuit.

Note: Some circuit breakers are plug-in type only on the supply side, while the load terminals are generally wire-type.

Drawer type circuit breaker

In addition to the disconnecting contacts, the circuit breaker also has a set of isolating contacts that are isolated from the main circuit. When in the withdrawn position, the circuit breaker can achieve an isolation distance that meets the specified requirements.

Plastic case circuit breaker

A circuit breaker having a housing made of molded insulating material as an integral part of the circuit breaker.

Vacuum circuit breaker

A circuit breaker whose contacts open and close in a high vacuum tube.

Gas circuit breaker

A circuit breaker in which the contacts open and close in a gas other than atmospheric air or air at a higher pressure.

Switching current release

During the closing operation, if the connected current exceeds the preset value, the circuit breaker will not be disconnected with any artificial delay, and it will not operate when the circuit breaker is in the closed position.

Short circuit release

Overcurrent release for short circuit protection.

Short-time delay short-circuit release

Overcurrent release for operation after a short delay

Alarm switch

An auxiliary switch connected to a circuit breaker that operates only when the circuit breaker is tripped.

Circuit breaker with locking device to prevent closing

A circuit breaker that prevents each contact from closing (i.e., closing sufficient to energize) even if a closing command is given while specified conditions still exist.

Short circuit breaking (or connecting) capability

The breaking (or connecting) capacity under specified conditions, including short circuit of the terminals of the switching device.

Ultimate short-circuit breaking capacity

The circuit breaker is not required to continuously carry the breaking capacity of its rated current capacity under the conditions specified in the specified test procedure.

Operating short-circuit breaking capacity

The circuit breaker is required to continuously carry the breaking capacity of its rated current capacity under the conditions specified in the prescribed test procedure.

Disconnection time

- For direct-acting circuit breakers, the moment when the off-time begins is the moment when the current increases enough to cause the circuit breaker to start operating.

- For circuit breakers operated by any form of auxiliary power supply, the opening time begins at the moment when the auxiliary power supply is applied or disconnected to the disconnect release.

Note: For circuit breakers, the “disconnection time” is usually called the “tripping time”. Strictly speaking, the tripping time refers to the time between the moment the disconnection operation begins and the moment the disconnection command becomes irreversible.

Overcurrent protection coordination

An overcurrent coordination of two overcurrent protection devices connected in series, in which the power supply side protection device (usually the power supply side, but not necessarily the power supply side device) realizes overcurrent protection with or without the help of another protection device and prevents overload of the other protection device.