A direct-acting low-pressure switch opens its contacts on?

The direct-acting low-pressure switch opens its contacts on a drop in suction pressure. This kind of switch is designed to monitor the pressure in the suction line of the refrigeration system. When the suction pressure decreases to a predetermined level, it activates the switch to open its contacts, interrupting the circuit, and typically stopping the compressor. This functional role is crucial in preventing damage to the compressor that could occur if it were to operate under low pressure conditions for an extended period.

In refrigeration systems, maintaining the appropriate suction pressure is vital for ensuring efficient operation and preventing issues such as compressor overheating or failure. The design of the low-pressure switch allows it to safeguard the system by responding specifically to drops in suction pressure, making it a protective mechanism within the broader context of system control and reliability.