China 40.5kV Three Phase Vacuum Circuit Breaker Manufacturer, Supplier, Factory

Kexun Electric Co., Ltd. supplies the 40.5kV Three Phase Vacuum Circuit Breaker as a synchronised switching unit for 35 kV overhead feeders, where one command must open or close all three poles together. A single spring mechanism drives the three interrupters through a common shaft, so phase spread stays within 2 ms and the whole operation finishes inside 100 ms for closing and 50 ms for opening. The same frame accepts motor or manual spring charging, an over-current trip coil and the rated reclosing cycle, which is what makes the unit useful on remote poles where a reclose attempt is the first line of fault recovery. As a China manufacturer with English-speaking export managers, Kexun also builds to customer drawings and samples as an OEM order.

One Signal, Three Phases

The closing command enters one electromagnet and releases the stored energy through one shaft, so all three poles move in lockstep. The opening and closing difference across the three poles is held to 2 ms, which is the figure a protection engineer checks first after installation. This behaviour is what a 40.5kV Three Phase Vacuum Circuit Breaker is specified for on a feeder where unbalanced switching would stress the line and the transformer winding.

How the Command Reaches Each Pole

Charging by Motor or Hand

The closing spring stores energy either from the built-in motor on the same AC/DC 220 V control supply or from a hand crank on the side of the mechanism box. Motor charging runs automatically after each operation, so the unit is ready for the next close without a crew on site. When the station supply is down during commissioning, the operator turns the shaft by hand and the same gear train compresses the spring; closing and tripping are then released through the fork on the half shaft.

Why Two Ways Matter

On a remote pole the motor keeps the unit armed between faults. On a new installation the hand crank lets the crew test the mechanism before the auxiliary supply is energised. Both paths feed the same spring, so the closing speed of 0.4 to 0.8 m/s and the opening speed of 1.4 to 1.8 m/s are the same whether energy came from the motor or from the crank.

Reclosing in Sequence

The rated operating sequence is 分－0.1s－CO－3s－CO-6sCO-60s, meaning one trip, an open interval of 0.1 s, a close-open, a 3 s rest, a close-open, and a final close after 60 s. That cycle mirrors the way distribution faults are cleared: most are transient, and a reclose after a short dead time restores supply without a crew. The mechanism recharges the spring between each stage, so the timing is set by the gear train rather than by the operator. The sequence is the rated duty the unit is tested to, and it is the behaviour a 40.5kV Three Phase Vacuum Circuit Breaker is selected for on a feeder where automatic reclose is standard practice.

Ratings Behind the Sequence

The sequence above runs on the published ratings listed below.

Trip Coils and Overcurrent

Closing and tripping electromagnets run on the same AC/DC 220 V control supply as the motor, and a separate over-current trip coil reacts to the current sensed on the line side. The over-current path is independent of the control supply, so a fault still trips the breaker even when the auxiliary supply has failed. Secondary circuits pass a 2 kV, one-minute power-frequency test before dispatch, which is the level that matters when control wiring runs in the same trench as the line cable.

What the Trip Coil Sees

The over-current trip coil is fed from the current transformer option chosen by the buyer, and it releases the opening spring directly. Once tripped, the unit waits for the motor or the hand crank to recharge before it can close again. This two-step sequence is what prevents an uncontrolled close onto a permanent fault.

Proving Timing on Site

After erection, a commissioning engineer checks closing time at no more than 100 ms, opening time at no more than 50 ms, closing bounce at no more than 5 ms and the three-phase spread at no more than 2 ms, using a timing analyser connected to the auxiliary contacts. Loop resistance per phase is measured and kept below 80 μΩ, which doubles as a joint-tightness check. These are the same numbers printed on the data sheet, so a field report can be compared directly against the factory record. On this model the timing windows are narrow enough to be rechecked after years of service rather than assumed.

Settings Used in Timing Checks

Timing is checked against the mechanical settings listed below.

Service and OEM Work

Kexun Electric Co., Ltd. accepts OEM orders built to customer drawings or samples, with a detailed discussion before production and a start only after the buyer confirms the drawing. Warranty runs 12 to 24 months depending on the order terms, and the export sales managers communicate in English, so a commissioning question does not wait for translation.

Frequently Asked Questions

Q: How do the three poles stay in step on a closing command?

A: One closing electromagnet releases one charged spring, and the spring drives all three poles through a common shaft. The opening and closing difference across the three poles is held to 2 ms, and closing bounce stays below 5 ms, so the timing does not drift between poles after long service.

Q: What happens to reclosing when the station battery is dead?

A: The hand crank on the mechanism box charges the same spring the motor would have charged, and the closing and tripping releases are then operated through the fork on the half shaft. The over-current trip coil still reacts to line current, independently of the control supply.

Q: Can you build the breaker to our own drawings?

A: Yes. Kexun Electric Co., Ltd. accepts OEM work to customer drawings or samples, with a detailed discussion before production and a start only after the buyer confirms the drawing. The 40.5kV Three Phase Vacuum Circuit Breaker is built to that confirmed drawing, the warranty runs 12 to 24 months, and English-speaking export managers handle the enquiry.

Q: How long is the warranty?

A: Warranty runs from 12 to 24 months depending on the order terms. Service support covers commissioning questions answered in English, and the export team replies so that a fault report does not wait for translation.

Q: What timing checks are needed after installation?

A: Closing time, opening time, closing bounce and three-phase spread are measured with a timing analyser on the auxiliary contacts, and loop resistance per phase is checked below 80 μΩ. The target figures are no more than 100 ms closing, no more than 50 ms opening, no more than 5 ms bounce and no more than 2 ms spread.

Q: What control voltage does the mechanism use?

A: The motor, the closing electromagnet and the tripping electromagnet all run on AC/DC 220 V, which covers the usual station battery and AC auxiliary arrangements. The secondary circuit passes a 2 kV, one-minute power-frequency test before dispatch.

Q: Does the over-current trip need an external supply?

A: No. The over-current trip coil reacts to the current sensed on the line side and releases the opening spring directly, so a fault trips the unit even when the AC/DC 220 V auxiliary supply has failed.

Q: What is the minimum order?

A: The minimum order is one set. Standard models are held in stock, which keeps the delivery period short, and payment is by T/T or L/C. Buyers are welcome to visit the Yueqing plant, and the company exhibits at trade fairs at home and abroad.

Operation You Can Repeat

One command, three poles, a spring that recharges itself, and a reclosing cycle that the mechanism runs without a crew: the ZW7-40.5 unit is built to be operated again and again across 10,000 mechanical operations. With motor or hand charging, an independent over-current trip and timing windows narrow enough to recheck on site, it fits a 35 kV feeder where automatic restoration matters more than routine visits. As a China OEM that works from customer drawings, Kexun Electric Co., Ltd. supplies the 40.5kV Three Phase Vacuum Circuit Breaker with a warranty of 12 to 24 months and English-speaking export managers on every enquiry.