Oil Circuit Breaker
Oil circuit breaker security shown here is a pressure-driven electrical control security, designed to protect the compressor against damage from loss of oil pressure. It is used for compressors in many commercial and industrial systems to ensure adequate oil pressure in any refrigerant pressure and temperature.
Oil circuit breaker security measures differential pressure. In the model shown, differential pressure, engine oil by placing pressure suction plus spring pressure on one side of the switch (on the left), and the suction pressure plus oil pressure on the other side (pictured right).
When the differential is adequate, the suction pressure plus oil pressure overcomes the suction pressure plus spring pressure. This action pushes the sliding contact the left, as shown in box. This separates the contacts, which activate the resistance of the heater. While the heater is switched off, the bimetallic remains in a vertical position, holding the control circuit compressor contactor closed.
If the drops too low, however, the sliding contact is placed on the right. This closes the electric heater circuit, as shown on the main chart. After a short time, bimetallic will deformation of the left, which opens to the control circuit shuts down the compressor.
When the compressor starts, oil pressure differential takes some time to build up normal. During this period, the bimetallic control circuits in their normally closed positions. Contacts, install the heater were also closed because oil low pressure discharge. Time spent bimetallic to deformation and break the chain of control of the compressor to the desired time delay for oil pressure rise high enough to break the chains of the heater. This process allows the compressor to continue. If the pump doesn't come until normal pressure in the compressor control circuit is broken, and the compressor stops.