Knife switches are a more or less obsolete type of power switch used in the 1800s. The live (hot) parts of the switch are uncovered and uninsulated, and they are unsuitable for use at shock-risk voltages.
Some common types are: - Single throw knife switch: This type has a single blade that engages with only one slot to make or break a circuit. - Double throw knife switch: This type has a blade that is hinged between two slots and can engage with either one to switch between two circuits.
HD knife switch and knife-shaped transfer switch (hereinafter referred to as the switch) is applicable for the complete set of distribution unit with the AC frequency of 50Hz, rated current up to 380V and the rated current up to 3000A, to turn on and off the AC and DC circuit in an infrequent manner or serve as isolation switch
Some knife disconnect switches have a lever to operate the blade, while others require manual insertion or removal. Knife disconnect switches can be single-pole or double-pole, and can have different ratings for voltage and current. What Is Knife Disconnect Switch? Knife Switch Types. 2 What is a knife switch used for?
Current flows through the switch when the knife is pushed into the jaw. Knife switches can take several forms, including single-throw, in which the knife engages with only a single slot, and double-throw, in which the knife hinge is placed between two slots and can engage with either one.
Open knife switches were supplanted by safety switches with current-carrying contacts inside metal enclosures which can only be opened by switching off the power. In modern applications, automatic switches (such as contactors and relays) and manual switches such as circuit breakers are used.