Regarding the installation of a pressure controller on the pump, interlock devices
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There is a pump, and it is there to prevent the pump from continuing to run idly after the material has been pumped out, which could cause damage to the pump. A pressure controller needs to be installed on the pump; when the pump is running, if the pressure drops below the lower limit set by the pressure controller, the pump will stop operating. If the pressure is low while the pump is running, it’s simple to stop the pump – just use upper and lower limit switches for that purpose. . . But the problem now is that with this electric shock protection in place, the pump cannot be turned on, because when the pump is not in use, the pressure controller remains disconnected. Could someone experienced help take a look? What should be done in this situation?
{:3_50:} Don’t ask why a pressure controller is needed on the pump, or why a level interlock device isn’t installed. Because the manager said a pressure controller needed to be added; I don’t know how they discussed it at the time – instead of adding a level interlock, they decided to add a pressure interlock.
Closed contacts are used; the contacts disconnect once the set value is reached
What about adding a time relay to the circuit? The time relay coil is connected in series with the pressure switch, while the normally closed contacts of the time relay are connected in parallel across the pressure switch.
Could the low pressure signal be combined with the pump operation signal and a delay be applied? The pump should be stopped when both the low pressure signal and the pump is in operation；
This issue shouldn’t be handled by the instrument panel; instead, the electrical system should be used to add the “low current protection” for the motor’s comprehensive protection. All modern magnetic pump models are equipped with low-current protection
And if pressure control interlocks must be added, that’s also fine! First, let the process operate the pump manually; once it’s stable, switch back to automatic mode. This means the technical requirements are a bit higher! And the pump has to be started on-site each time
Insert the pump start/stop signal into the control circuit
I think it’s done that way too,:handshake
Create a bypass for the pressure signal; it can be activated after the pump starts operating. There’s no need for such complexity – proper management will suffice~~
No no no, in my case the contacts break apart under pressure or when the pressure is low; using a normally closed type cannot achieve what I need.