TAH-97029N (0258) page 1 of 5
Tachometer and Tach/Hourmeter Installation Instructions
Series: ATS, ATHS, ATA, ATHA, ATHI
TAH-97029N
Revised 08-07
Section 20
(00-02-0258)
Description
These tachometers are indicators of engine revolutions per minute (RPM). Models
equipped with hourmeter also record elapsed engine running time.
Alternator driven models function from pulses generated by an alternator with 4, 8, 12,
14, or 16 poles on the rotor. For magnetic sensor (pickup) driven models, the pulses are
obtained from the ring gear of an engine’s flywheel (having from 70 to 225 teeth) using
an electromagnetic sensor (pickup).
Ignition signal driven models available for 4, 6 and 8 cylinder, spark ignited engines.
All units are for negative ground, positive ground or isolated electrical systems. If the
instrument is connected reverse polarity, it will not operate until proper connections are
made. All units are powered by 12 VDC. For 24 VDC applications, an optional
ATVC12/24 converter must be used (see Fig. 3 or Fig. 5).
Specifications
Power Input:
12 VDC (11.5 – 16 V) [0.84 to 1.44W].
Backlight:
3 to 4.7W
RPM Input Signal Voltage:
1.5 Vrms minimum from a magnetic pickup or
alternator (minimum 3-pole).
Accuracy:
Tachometer:
± 2% full scale.
Hourmeter:
± 0.01% hours, ± 1 count.
Temperature Range:
-5°F to 185°F (-20°C to +85°C).
Dial (Face Plate):
270° sweep with white numerals
(over black background)
Bezel:
304 Stainless Steel.
Scale:
0-3000 RPM and 0-4000 RPM (ATHA-40-12-A model only)
Case Material:
Plastic.
Hourmeter Range:
Measures elapsed time:
100,000 hours in 0.1 increments.
Models
Magnetic Sensor Tachometer 3000 RPM; 70 - 225 pulses 12 VDC
Model #
Designation
ATS-30-12
Bright Stainless Steel Bezel
ATS-30-12-A
Black Stainless Steel Bezel
ATS-30-12-B
SAE Bright Stainless Steel Bezel
ATS-30-12-C
SAE Black Stainless Steel Bezel
Magnetic Sensor Tach/Hourmeter 3000 RPM; 70 - 225 pulses 12 VDC
ATHS-30-12
Bright Stainless Steel Bezel
ATHS-30-12-A
Black Stainless Steel Bezel
ATHS-30-12-B
SAE Bright Stainless Steel Bezel
ATHS-30-12-C
SAE Black Stainless Steel Bezel
Alternator Signal Tachometer 3000 RPM; 3 - 27 pulses 12 VDC
ATA-30-12
Bright Stainless Steel Bezel
ATA-30-12-A
Black Stainless Steel Bezel
ATA-30-12-B
SAE Bright Stainless Steel Bezel
ATA-30-12-C
SAE Black Stainless Steel Bezel
Alternator Signal Tach/Hourmeter 4000 RPM; 3 - 27 pulses 12 VDC
ATHA-30-12
Bright Stainless Steel Bezel
ATHA-30-12-A
Black Stainless Steel Bezel
ATHA-30-12-B
SAE Bright Stainless Steel Bezel
ATHA-30-12-C
SAE Black Stainless Steel Bezel
ATHA-40-12-A
Black Stainless Steel Bezel
Ignition Signal Tach/Hourmeter 4000 RPM; 4, 6 or 8 cylinder 12 VDC
ATHI-40-12-A
Black Stainless Steel Bezel
Optional Items and Replacement Bulbs
ATVC12/24
24 VDC to 12 VDC Converter
00-00-4617
12 VDC Light Bulb
00-00-4618
24 VDC Light Bulb
GENERAL INFORMATION
Please read the following instructions before installing
.
A visual inspection is recommended before mounting.
General Information and these installation instructions are intended for all Tachometer and Tachometer/Hourmeter models.
Mount these units in a place where they will be protected from rain and splashing
water.
A minimum distance of 12 in. (305 mm) from any coil, coil leads, or high volt-
age wiring should be maintained. These units are intended for mounting in a flat
panel. Cut a 3-3/8 in. (86 mm) diameter hole as shown below. Remove the mounting
bracket from the back of the unit. Insert the instrument from the front side of the
panel and replace the mounting bracket to secure the instrument in place.
Case Mounting Instructions
3-53/64 in.
(97 mm)
3-5/8 in.
(92 mm)
21/32 in.
(17 mm)
3-3/8 in. min.
(86 mm)
Mounting Hole
RPM
x 100
HOURS
1
10
WARNING
BEFORE BEGINNING INSTALLATION OF THIS MURPHY PRODUCT
✔
✔
Disconnect all electrical power to the machine.
✔
✔
Make sure the machine cannot operate during installation.
✔
✔
Follow all safety warnings of the machine manufacturer.
✔
✔
Read and follow all installation instructions.
Front View
Side
View
Mounting Bracket
Mounting Hole
For a selection of Magnetic Sensors (pickups) see
installation instructions document MP-8802N.
