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Differential pressure switch

MP 54 and MP 55 oil dierential pressure

switches are used as safety switches to protect

refrigeration compressors against low

lubricating oil pressure.

If the oil pressure fails, the oil dierential

pressure switch stops the compressor after a

certain time period.

MP 54 and MP 55 are used in refrigerating

systems using HCFC and non-ammable HFC

refrigerants.

MP 55A is used in refrigerating systems with

R717. MP 55A can also be used in systems with

HCFC and non-ammable HFC refrigerants.

MP 54 has a xed dierential pressure setting. It

also incorporates a thermal time relay with a

xed release time setting.

MP 55 and MP 55A have adjustable dierential

pressure and are available both with and

without thermal time relay.

Features

• Wide regulating range

• Can be used for deep freeze, refrigeration and

air conditioning plant

• Can be used for HCFC and non-ammable

HFC refrigerants

• Electrical connection at the front of the unit

• Suitable for both alternating and direct

current (AC and DC)

• Screwed cable entry for cables from 6 – 14

mm diameter

• Small contact dierential

AI211986438834en-000901

Data Sheet

Diﬀerential pressure switch

Type MP 54, 55 and 55A

MP 54 and MP 55 are used in refrigerating systems

using HCFC and non-ammable HFC refrigerants.

Summary of content (8 pages)

PAGE 1
Data Sheet Differential pressure switch Type MP 54, 55 and 55A MP 54 and MP 55 are used in refrigerating systems using HCFC and non-flammable HFC refrigerants. MP 54 and MP 55 oil differential pressure switches are used as safety switches to protect refrigeration compressors against low lubricating oil pressure. If the oil pressure fails, the oil differential pressure switch stops the compressor after a certain time period.
PAGE 2
Differential pressure switch, Type MP 54, 55 and 55A Functions Danfoss 60B55.13 Figure 1: Electrical diagram If there is no oil pressure on starting, or if the oil pressure falls below the set pressure during operation, the compressor will stop after the release time has elapsed. The electrical circuit is divided into two completely separate circuits: a safety circuit and an operational circuit.
PAGE 3
Differential pressure switch, Type MP 54, 55 and 55A Figure 3: Functions for During operation Pos. C: The lubricating oil pressure falls during operation to a value lower than the set/fixed differential. At point C, safety circuit T1-T2 cuts in and the timer is activated. Pos. D: The lubricating oil pressure reaches the set/fixed differential plus the contact differential before the timer period elapses. At point D, safety circuit T1-T2 cuts out and the timer is stopped, i.e.
PAGE 4
Differential pressure switch, Type MP 54, 55 and 55A Product specification Design and Materials Figure 4: Design for MP 54, MP 55 and MP 55A 2 4 3 1 Connection to pressure side of lubrication system, OIL 2 Connection to suction s ide of refrigeration plant, LP 3 Setting disk (MP 55 and MP 55A) 4 Reset button 5 Test device 5 1 The operation of the pressure switch relies only on the differential pressure, i.e.
PAGE 5
Differential pressure switch, Type MP 54, 55 and 55A Features Specifications Enclosure IP20 to EN 60529 / IEC 60529 MP with time relay (contacts M-S) Contact loads MP without time relay Wire dimensions AC15 = 2 A, 250 V DC13 = 0.2 A, 250 V AC15 = 0.1 A, 250 V DC13 = 12 W, 125 V solid / stranded 0.2 – 1.5 mm2 flexible, without ferrules 0.2 – 1.5 mm2 flexible, with ferrules 0.2 – 1 mm2 Tightening torque max. 1.
PAGE 6
Differential pressure switch, Type MP 54, 55 and 55A Ordering Figure 6: MP 55E Table 3: For R22, R134a, R404A, R407A, R407C, R407F, R422B, R422D, R448A, R449A, R450A, R452A, R507A, R513A Operation range, LP side Relay release time [bar] [bar] [s] 1⁄4 in Flare 1 m cap.tube 1⁄4 in ODF solder M12 x 1.5 with 6 mm cutting ring 0.65 -1 – 12 0(1) 060B029791 - - 0.65 -1 – 12 45 060B016691 - - 0.9 -1 – 12 60 060B016791 - - 0.65 -1 – 12 90 060B016891 - - 0.
PAGE 7
Differential pressure switch, Type MP 54, 55 and 55A Certificates, declaration and approvals The list contains all certificates, declarations, and approvals for this product type. Individual code number may have some or all of these approvals, and certain local approvals may not appear on the list. Some approvals may change over time. You can check the most current status at danfoss.com or contact your local Danfoss representative if you have any questions.
PAGE 8
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