Murphy A20 Series 사용자 설명서
Bulletin AT-95026B page 1 of 4
2 and 2-1/2 in. (51 and 64 mm) Dial
■
Corrosion Resistant Polycarbonate Case
■
Indicating Gage and Limit Switch
■
Switch Can Activate Alarms and/or Shut
Down Equipment
Down Equipment
■
Critical/High Temperature Limit Switch
Is Visible and Adjustable (Most Models)
Is Visible and Adjustable (Most Models)
■
Contact(s) Isolated From Ground
Description
The A20 Series (2 inch/51 mm dial) and the A25
Series (2-1/2 inch/64 mm dial) SWICHGAGE
Series (2-1/2 inch/64 mm dial) SWICHGAGE
®
mod-
els are diaphragm-actuated, temperature-indicating
gages, with built-in electrical switches for tripping
alarms and/or shutdown devices.
Ranges are available from 32-120°F (0-45°C) thru
300-440°F (160-220°C).
All models of these rugged, built-to-last instruments
are fully sealed from the environment by the unique
combination of a polycarbonate case and lens, a pol-
ished stainless steel bezel, and O-ring seals.
These vapor/pressure actuated gages feature a sealed
capillary tube and a sensing bulb. When subjected to
heat, the liquid in the sensing bulb changes to vapor
creating pressure against a diaphragm mechanism.
The diaphragm translates this vapor pressure into a
mechanical gage reading.
For series A20T and A25T, the gage pointer acts as a
temperature indicator and as one switch pole which
completes a circuit when it touches the adjustable limit
contact. Contact(s) are isolated from ground. They have
self-cleaning motion to enhance electrical continuity.
Models A20TE and A25TE have internal snap-acting
SPDT switches.
Gage-only models, without contacts
(MURPHYGAGE
gages, with built-in electrical switches for tripping
alarms and/or shutdown devices.
Ranges are available from 32-120°F (0-45°C) thru
300-440°F (160-220°C).
All models of these rugged, built-to-last instruments
are fully sealed from the environment by the unique
combination of a polycarbonate case and lens, a pol-
ished stainless steel bezel, and O-ring seals.
These vapor/pressure actuated gages feature a sealed
capillary tube and a sensing bulb. When subjected to
heat, the liquid in the sensing bulb changes to vapor
creating pressure against a diaphragm mechanism.
The diaphragm translates this vapor pressure into a
mechanical gage reading.
For series A20T and A25T, the gage pointer acts as a
temperature indicator and as one switch pole which
completes a circuit when it touches the adjustable limit
contact. Contact(s) are isolated from ground. They have
self-cleaning motion to enhance electrical continuity.
Models A20TE and A25TE have internal snap-acting
SPDT switches.
Gage-only models, without contacts
(MURPHYGAGE
®
) are also available.
Applications
Applications for A20 and A25 Series temperature
SWICHGAGE
SWICHGAGE
®
instruments include: engines and
equipment in Oil Field, Marine, Irrigation, Construction
and Trucking industries. Monitoring Engine Coolant
temperature, Crankcase Oil, Transmission Oil.
and Trucking industries. Monitoring Engine Coolant
temperature, Crankcase Oil, Transmission Oil.
Specifications
Dial: White on black; U.S.A. standard scale is dual
scale °F/°C; others available.
Case: Glass filled/Polycarbonate, corrosion-resis-
tant; steel mounting clamp included. Bezel:
Polished stainless steel, standard; others
are available.
Polished stainless steel, standard; others
are available.
Pointer: Tempered nickel silver; red tip.
Lens: Polycarbonate, high-impact.
Sensing Element: Beryllium copper diaphragm.
Capillary: PVC armored copper; 4 ft. (1.2 m).*
Lens: Polycarbonate, high-impact.
Sensing Element: Beryllium copper diaphragm.
Capillary: PVC armored copper; 4 ft. (1.2 m).*
Stainless steel armor optional.
Sensing Bulb: Copper.*
Gage Accuracy: See accuracy chart, on page 2.
Maximum Temperature: See Temperature Ranges
Gage Accuracy: See accuracy chart, on page 2.
Maximum Temperature: See Temperature Ranges
and Factory Settings table on page 2.
Adjustable Limit Contact (A20T and A25T):
SPST contact; pilot-duty only, 2 A @ 30 VAC/
VDC; isolated from case ground. Normally Closed
when the high limit is met. Normally Open when
pointer is in normal operating range. Contacts are
gold flashed silver.
Limit Contact Adjustment: by a 1/16 in. hex
VDC; isolated from case ground. Normally Closed
when the high limit is met. Normally Open when
pointer is in normal operating range. Contacts are
gold flashed silver.
Limit Contact Adjustment: by a 1/16 in. hex
wrench thru 100% of the scale.
Wiring: A20T: Number 4 screw terminals;
A25T: Number 6 screw terminals.
Snap-Switch Rating (A20TE and A25TE):
SPDT, 3 A@ 30 VDC inductive; 4 A @
125 VAC inductive.
Wiring: A20TE: Number 4 screw terminals;
A25TE: Number 6 screw terminals.
Unit Weight: A20 Series: 11.9 oz. (0.370 kg).
A25 Series Models: 13.3 oz. (0.413 kg).
Unit Dimensions: A20 Series: 4-3/4 x 4-3/4 x 3 in.
(121 x 121 x 76 mm). A25 Series Models: 4-3/4 x
4-3/4 x 2-3/4 in. (121 x 121 x 70 mm).
4-3/4 x 2-3/4 in. (121 x 121 x 70 mm).
Base Models
Coolant or Oil Temperature
A20T and A25T Series SWICHGAGE
®
For these models the gage pointer makes with an
adjustable contact to complete a pilot-duty circuit.
adjustable contact to complete a pilot-duty circuit.
A20TL and A25TL SWICHGAGE
®
For use on Ford Worldwide engines. Supplied with
special sensing bulb.
special sensing bulb.
A20TE and A25TE SWICHGAGE
®
A20TE (was A20ESR) and A25TE (was A25ESR).
Models with internal SPDT snap-switches, instead
of the single pole/pointer contact(s). When the
switch closes on rising temperature, it becomes Set.
As temperature decreases the switch Resets.
Model A25TE is CSA listed for
non-hazardous areas. Model
A25TE-EX is CSA listed for
Class I, Division 1, Groups
C & D hazardous areas.
Models with internal SPDT snap-switches, instead
of the single pole/pointer contact(s). When the
switch closes on rising temperature, it becomes Set.
As temperature decreases the switch Resets.
Model A25TE is CSA listed for
non-hazardous areas. Model
A25TE-EX is CSA listed for
Class I, Division 1, Groups
C & D hazardous areas.
A20TABS and A25TABS SWICHGAGE
®
Same as 20 and 25T with internal SPDT snap-
switch for pre-alarm.
switch for pre-alarm.
Cylinder Head Temperature
A20TH and A25TH SWICHGAGE
®
A20TH (was A20TL8133) and A25TH (was
A25TL8133). For use on Air Cooled engines.
A25TL8133). For use on Air Cooled engines.
Gage–Only Models
A20TG and A25TG MURPHYGAGE
®
Gage without contact(s).
*
For optional capillary lengths, engine adapters, sensing bulbs
and range combinations, see Murphy bulletin T-8428B.
**
Products covered by this bulletin comply with EMC Council
directive 89/336/EEC regarding electromagnetic
compatibility except as noted.
compatibility except as noted.
A20T Series
shown
shown
**
AT-95026B
Revised 08-05
Catalog Section 10
A20 and A25 Series
Temperature SWICHGAGE
Temperature SWICHGAGE
®