Murphy TAH-97026B User Manual

■

3000 and 4000 RPM –0 to 100,000 hours

■

Sensing from Magnetic Sensor, Battery
Charging Alternator or Ignition Signal

■

High Visibility Analog Readout

■

Air Core Movement

■

Easy Calibration

■

Through Dial Lighting

■

Powered by 12 VDC Battery
Available Converter for 24 to 12 VDC

Description

The AT Series tachometers are rugged, transis­torized instruments with solid-state circuitry for
indication of engine RPM. They are equipped
with a bracket for mounting into a standard 3­3/8 in. (86 mm) dash mounting hole. A full 270°
sweep of the pointer gives an accurate indication
on a large easy–to–read scale and the dial can be
illuminated for night reading. The ATH Series
models are also equipped with hourmeter to
record the elapsed running time of an engine.

Models available for Alternator, Magnetic
Sensor or Ignition signal

These instruments are designed to function from
pulses generated by an alternator with 4, 8, 12,
14, or 16 poles on the rotor. The pulses can also
be obtained from the ring gear of an engine by
means of an electromagnetic sensor (magnetic
pickup). Murphy’s magnetic sensor driven mod­els are designed to function with flywheels hav­ing anywhere from 70 to 225 teeth.
Ignition signal model available for 4, 6 or 8
cylinder, spark-ignated engines.
All models are for negative ground, positive
ground or isolated electrical systems and are
protected against reverse polarity hookup.

All models are powered by 12 VDC and are
reverse polarity protected.

Series Models

ATS Series Magnetic Sensor Signal Tach

70 - 225 pulses*12 VDC, 2733 Hz to 13.62 kHz
@ 3000 RPM

ATHS Series Magnetic Sensor Signal
Tachometer/Hourmeter

70-225 pulses*12 VDC, 2733 Hz to 13.62 kHz @
3000 RPM

ATA Series

Alternator Signal Tachometer

3-27 pulses*12 VDC, 137 to 1330 Hz @ 3000 RPM

ATHA Series

Alternator Signal

Tachometer/Hourmeter

3-27 pulses*12 VDC, 137 to 1330 Hz @ 3000 RPM
or 193 to 1815 Hz @ 4000 RPM

ATHI Series

Ignition Signal

Tachometer/Hourmeter

4, 6 or 8 cylinder engines @ 4000 RPM

Applications

These tachometers are specially designed for use
on truck, marine, industrial, or stationary engines.

Specifications

Power Input: 12 VDC (11.5 to 16 V)

[0.84 to 1.44W].

Back Light: 3 to 4.7 W.
RPM Input Signal Voltage: 1.5 Vrms min. from a

magnetic pickup or alternator (minimum 3-pole).

Accuracy: Tachometer: ± 2% full scale.

Hourmeter: ± 0.01% hours, ± 1 count.

Temperature Range: -5 to 185°F (-20 to +85°C).
Dial: 270° sweep (white numerals over black)
Bezel: 304 Stainless Steel.
Scales: 0 - 3000 RPM or 0 - 4000 RPM†.
Case Material: Plastic.
Hourmeter Range: Measures elapsed time:

100,000 hours in 0.1 increments (tenths).

Shipping Weight: 0.89 lb. (403 g).
Shipping Dimensions: 5-1/2 x 5-1/2 x 5-1/2 in.

(140 x 140 x 140 mm).

AT and ATH Series

Bezel Styles

bright stainless

black stainless

bright SAE

black SAE

**

TAH-97026B

Revised 05-05

Catalog Section 20

(00-02-0260)

Tachometers and Tach/Hourmeters

TAH-97026B page 1 of 2

*

To determine pulses per engine revolution, work the
formulas on the back page and use the pulses per revolu­tion number to determine if the tachometer can be used
for your application.

**

Products covered by this bulletin comply with EMC
Council directive 89/336/EEC regarding electromagnetic
compatibility except as noted.

†

Range available only for ATHA-40-12-A; ATHI-40-12-A

How to Determine if the Tachometer or Tach/
Hourmeter is Suitable for Your Equipment

A. Ignition sensing Tach/hourmeters can be used on 4, 6 or 8 cylinder, spark

ignited engines.

B. Magnetic pick up sensing Tachometer or Tach/hourmeters will operate from

70 to 225 tooth flywheels.

C. Alternator sensing Tachometer or Tach/hourmeters will operate from 3 to 27

pulses per engine revolution. To obtain the number of pulses per engine revo­lution, work the following formulas:

1. Determine the number of poles on your alternator. Look for the

designation/type in the manufacturer's manual or remove the
pulley and fan to count the number of poles on the rotor.

2. The ALTERNATOR TACHOMETER CHART lists common

alternators and their minimum and maximum pulley ratios.
Determine pulley ratio with the following formula:

PULLEY RATIO=

CRANK SHAFT PULLEY DIAMETER
ALTERNATOR PULLEY DIAMETER

3. Check that Pulley Ratio falls within the range shown on the
PULLEY RATIOS CHART for a particular alternator. If ratio falls

in the shaded area, the tachometer can be calibrated for the application.

4. To determine the pulses per engine revolution:

NUMBER OF POLES

X PULLEY RATIO = PULSES PER ENGINE REVOLUTION

2

ALTERNATOR TACHOMETER CHART

Manufacturer Designation/Type Poles

Minimum Maximum

*

pulley-ratio pulley-ratio

*

Although the tach may be calibrated for higher input frequencies in some cases, as shown on the

Pulley Ratio chart, pulley ratios in excess of 5.0 are NOT recommended nor are they normally used.

Prestolite
Load Handler
Load Handler
Leece Neville
Bosch
C.E. Neihoff
Delco Remy
Delco Remy
Delco Remy
Delco Remy
Delco Remy
Hitachi
Hitachi
Lucas
Mando
Motorcraft
Nippondenso
Powerline
Powerline
Valeo

All
88A, 8LHA, 89C, 8LHC
All 5 inch models
All
G and K Series
All
30DN
15SI, 21SI, 40DN, 40SI
10DN, 10SI, 12SI
20DN, 25SI, 27SI
29SI, 30SI
LT125, LT130, LT133
LT150
All
All
All
All
Series 23
Series 24, 25, 26
All

8
16
12
12
12
12

4
12
14
16
16

8
12
12
12
12
12
14
12
12

0.75

0.375

0.5

0.5

0.5

0.5

1.5

0.5

0.42

0.375

0.375

0.75

0.5

0.5

0.5

0.5

0.5

0.42

0.5

0.5

6.5

3.25

4.3

4.3

4.3

4.3
13

4.3

3.7

3.25

3.25

6.5

4.3

4.3

4.3

4.3

4.3

3.7

4.3

4.3

How to Order

Order the Tachometer or Tachometer/Hourmeter by model number.

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-40-12 Bright Stainless Steel Bezel
ATHA-40-12-A Black Stainless Steel Bezel
ATHA-40-12-B SAE Bright Stainless Steel Bezel
ATHA-40-12-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 Power Input Convertor
ATVC12/24

24 VDC to 12 VDC Converter

Dimensions

TAH-97026B page 2 of 2

Warranty

A limited warranty on materials and workmanship is given with this
FW Murphy product. A copy of the warranty may be viewed or printed
by going to www.fwmurphy.com/support/warranty.htm

INDUSTRIAL PANEL DIVISION

P.O. Box 470248
Tulsa, Oklahoma 74147 USA
[phone] fax [phone]
e-mail [e-mail]

MURPHY DE MEXICO, S.A. DE C.V.

Blvd. Antonio Rocha Cordero 300, Fracción del Aguaje
San Luis Potosí, S.L.P.; México 78384
[phone] fax [phone]
Villahermosa Office [phone]
e-mail [e-mail]
www.murphymex.com.mx

FRANK W. MURPHY, LTD.

Church Rd.; Laverstock, Salisbury SP1 1QZ; U.K.
[phone] fax [phone]
e-mail [e-mail]
www.fwmurphy.co.uk

In order to consistently bring you the highest quality, full featured products, we reserve the right to change our specifications and designs at any time.

FW Murphy

P.O. Box 470248
Tulsa, Oklahoma 74147 USA
[phone] fax [phone]
e-mail [e-mail]

www.fwmurphy.com

Printed in U.S.A.

PULLEY RATIOS CHART

RATIO

0.5 1.5

4

8

12

14

NO. OF POLES

16

2.0 2.5

3.0

3.5

4.0

4.5

5.0

Minimum Maximum

1.5 —– 13

0.75 —– 6.5

0.5 —– 4.3

0.42 —– 3.7

0.375 —– 3.25

3-53/64 in.

(97 mm)

RPM

x 100

HOURS

21/32 in.
(17 mm)

1
10

3-5/8 in.
(92 mm)

Mounting Hole

3-3/8 in. min.

(86 mm)