Single-phase, three-phase motor knife switch circuit

Knife switch used primarily for lighting, and 7 three-phase power circuit. 5kW electric motor start switch. That fuse is connected below it, so it can switch roles, but also can play a role in short circuit protection.
Knife switch consists of single-phase and three-phase two, 5 a, 10A, 15A, 30A, 100A, and other specifications. Knife switch three-phase wiring as shown in Figure 2-1. Knife switch is simple in structure, convenient maintenance and low cost advantages are widely used, but it charged closing, less able to spark arcing.
The shape of the knife switch three-phase wiring
In the installation, maintenance, and should note the following points when using the knife switch.
 
(1) knife switch should be installed vertically on the insulation Board should not paperback or flip; toolholder should be brought up at closing time, and should be installed in a moisture-proof, dust-proof, shock-proof place.
 
(2) the knife switch rated voltage should be greater than the power supply voltage, the rated current should be slightly greater than the maximum load current. If the knife switch control of small electric motors, choose the knife switch current rating should be 3 times times the motor rated current.
 
(3) knife switch with load operation, the body should as far as possible away from the knife switch, and action must be quickly, in order to avoid short circuits due to arcing and burn the body between the blade and the forehead.
 
(4) the charged operation knife switch must be upper and lower knife switch arc cover and tighten the captive screws, in order to enhance its ability to arc.
 
(5) install the knife switch, power cables should enter through the Terminal on, after passing the knife switch, fuse, terminals from the load. After receiving a good, want to try all took by the hand of wire, check that you pressed, in case the contact resistance increases burned out terminal screws