The electric contact pressure gauge has three lines, one of which is a public line, and the pointer is adjustable. One hand can be adjusted to 0.4M to connect the low-voltage start control relay, and the other hand can be adjusted to 0.6M to connect the high-voltage stop relay. The common line is a common line controlled by high and low voltage.
The upper pointer is the upper limit, the lower pointer is the lower limit, and the black pointer in the middle indicates the actual pressure value. When the actual pressure is higher than the upper limit, it is connected with the upper limit and disconnected with the lower limit.
When the actual pressure is between the upper and lower limits, the male terminal is disconnected from the upper and lower limits. When the actual pressure is lower than the lower limit, the male terminal is connected to the lower limit and disconnected from the upper limit. The electric contact pressure gauge is used to control the upper and lower limit pressures.
Extended data
Working process analysis of automatic control circuit of electric contact pressure gauge;
1, manual control:
Put the selector switch SA in the manual position, and its contact (1-3) is closed. When starting, press the start button SB2, its normally open contact (5-7) will be closed, the power supply of the KM coil loop of AC contactor will be turned on, the KM coil will be electrically attracted, the KM auxiliary normally open contact (5-7) will be closed and self-locked, and the KM three-phase main contact will be closed, and the water pump motor will be electrically started to run, driving the water pump to pump water.
2, automatic control:
Put the selector switch SA in the automatic position, and its contact (1 1) is closed. When the pressure of the electric contact pressure gauge is lower than the lower limit, the SP contact (7- 1 1) is closed, so that the KM coil of the AC contactor is attracted by electricity, the KM auxiliary normally open contact (7 1) is closed, and the self-locking KM three-phase main contact is closed, and the electricity of the water pump motor starts to operate, driving the water pump to pump water.
With the gradual increase of pressure, when the pressure is greater than the upper limit of SP, the SP contact (113) is closed, the power supply of KA coil loop of intermediate relay is turned on, KA normally closed contact (7-9) is turned off, the power supply of KM coil loop of AC contactor is turned off, the KM coil is released, the KM three-phase main contact is turned off, and the water pump motor stops running.