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General| Type | Pressure switch |
|---|---|
| Differential | Adjustable |
| Housing material | Thermoplastic |
| Refrigerants | R134a, R404A, R407C, R410A, R507, R22 |
| Approvals | UL |
| Connection size | 1/4 inch |
| Connection | Flare |
| Enclosure | IP20, IP44, IP55, IP66 (depending on model) |
| Protection class | IP20, IP44, IP55, IP66 (depending on model) |
| Operating temperature | -40°C to +70°C (-40 to +158°F) |
MP 54 and MP 55 are differential oil pressure switches for compressor protection against insufficient lubrication.
Suitable for freezing, refrigeration, and air conditioning systems with fluorinated refrigerants.
Electrical connections are located on the front of the unit.
MP 55A is for R 717 (NH3) systems but can also be used with fluorinated refrigerants.
MP 54 features a fixed differential and built-in thermal timer with fixed trip time.
MP 55 and 55A offer adjustable differential pressure and optional thermal timer.
Suitable for AC and DC power, with threaded cable entry for 6-14mm cables.
Features a small switching differential and complies with EN 60947.
Includes approvals from DEMKO, NEMKO, FIMKO, DSRK, Polski Rejestr Statków, Germanischer Lloyd, EZU, RINA, and CE mark.
UL and CSA approved versions are available upon request.
MP 54 uses stainless steel, drawn steel sheet, and tool steel for parts in contact with the medium.
MP 55/55A uses stainless steel, drawn steel sheet, and tool steel for parts in contact with the medium.
Details connections for lubrication system (OIL) and refrigeration plant suction (LP).
Includes setting disc for differential pressure adjustment and a reset button.
A test device is integrated for functional checks.
Operation depends on differential pressure, independent of absolute pressure on bellows.
MP 54 has a fixed differential, not adjustable via a setting disc.
Pressure difference between LP and OIL connections for control operation.
Oil pump pressure minus crankcase pressure at contact cut-in.
Pressure range on the LP connection for control operation.
Pressure rise above set differential needed to cut off time relay current.
Period compressor runs with low oil pressure during start-up and operation.
Compressor stops after release time if oil pressure is too low during start or operation.
Circuit is divided into separate safety and operational circuits.
Timer activates when oil differential pressure is below set value.
Timer deactivates when oil differential pressure exceeds set value plus contact differential.
Lubricating oil pressure builds up to set differential plus contact differential.
Compressor stops if oil pressure doesn't reach set differential before timer period elapses.
Oil pressure falls below set differential, activating safety circuit and timer.
Timer stops when oil pressure reaches set differential plus contact differential.
Compressor stops if oil pressure remains below set differential.
Pressing the internal test device should stop the compressor after the release time.
Restart is possible after ~2 minutes via reset button, once fault cause is determined.
Provides dimensional drawings for MP 54 and MP 55 units.
Provides dimensional drawings for the MP 55A unit.
Specifies the approximate weight of the unit as 0.8 kg.
