Chassis trucks are mainly used to carry components such as circuit breakers and transformers in withdrawable switchgear, and to push them in and push them out as auxiliary operations for connecting components and busbars. When the chassis truck works with the internal mechanism of the circuit breaker and other interlocks in the mid-set cabinet, it can meet the “five prevention” interlock requirements in GB3906. The specific functions are as follows:
1. The circuit breaker can only be closed when the handcart is in the test / isolating or working position. After the circuit breaker is closed, the handcart cannot be moved, thereby preventing the occurrence of misconnection and misclosing of the isolation contacts under load.
2. When the handcart is at the working position or about 10mm away from the test / isolating position, the earth switch cannot be closed to prevent the earth switch from being turned on by mistake.
3. When the earth switch is closed, the handcart cannot be moved from the test / isolating position to the working position to prevent the circuit breaker from closing when the earth switch is in the closing position.
4. After the chassis truck enters the cabinet, once it leaves the test / isolating position, the handcart cannot be withdrawn from the cabinet.
