SELECTRONIC® Digital Tachometer/TACHSWICH™
Installation Instructions
DT9800 Series
DT-8605N
Revised 07-97
Section 20
(00-02-0180)
®
Please read the following information before installing. A visual inspection of this product for damage during shipping is recommended before mounting. It is your responsibility to have a qualified person install this unit and make sure installation conforms to NEC and local codes.
GENERAL INFORMATION
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.
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*
Class I,
Division 2,
Group D
Description
The Digital SELECTRONIC® DT9800 series features a tachometer-only and tachometer with built-in overspeed switch. These tachometers are highly accurate and dependable due to digital solid-state electronics and a quartz crystal time base. The surface-mount enclosure makes it easy to install. Tachometer power and RPM data are supplied by a magnetic pickup or capacitor discharge (CD) ignition–depending on model chosen. The RPM data is converted and displayed on a four digit, easy-to-read liquid crystal display (LCD). The LCD displays up to 9999 RPM.
The DT9803 and DT9804 are tachometer-only models. The DT9803 is powered by a magnetic pickup. The DT9804 is powered by a CD ignition.
The TACHSWICH™ models, DT9805 and DT9806, combine a digital tachometer and overspeed switch. The DT9805 is powered by a magnetic pickup and the DT9806 is powered by a CD ignition.
Specifications
Input Signal Source
DT9803: 18 to 112 volts peak to peak or 3.5 to 40 Vrms. DT9805: 18 to 112 volts peak to peak or 7 to 40 Vrms. DT9804 and DT9806: 90 to 400 VDC, CD ignition.
Temperature Range: -4 to 158°F (-20 to 70°C).
Accuracy: ±1 RPM.
Frequency Range:
DT9803 and DT9805: 1 to 15 KHz.
DT9804 and DT9806: 3 to 666 Hz.
Overspeed Switch Rating (DT9805 and DT9806 only):
SCR output. 5 A @ 400 VDC.
*Class I, Div. 2, Group D Hazardous Locations. Models DT9803 and DT9805 magnetic pickup powered 18 to 112 Vpp input. Models DT9804 and DT9806 used with CD ignition. Contact Murphy for details. The equipment must be installed in a suitable enclosure accepted by local authorities.
MOUNTING
1.Before installing, be sure there will be enough clearance to access the calibration rocker switches and overspeed switches from the back of the panel.
2.Drill mounting holes according to the dimensions below.
3.Be sure the gasket is in place on the back of the tachometer before installing. Insert the tachometer from the front of the panel aligning the mounting studs with the appropriate holes. Secure the tachometer using the four 6/32 nuts, but do not overtighten the nuts as case damage could occur.
Mounting Hole Dimensions |
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Back View |
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Tachometer |
Gasket |
Panel |
Calibration Rocker |
Overspeed |
4 in. |
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Switches |
Switches** |
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(102 mm) |
2 in. |
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(51 mm) |
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3-1/8 in. |
2 in. |
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1 |
2 |
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4 |
5 |
6 |
7 |
8 |
9 10 11 12 |
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(79 mm) |
(51 mm) |
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OPEN |
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diameter |
8 |
0 |
2 |
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8 |
0 |
2 |
8 |
0 |
2 |
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9 |
1 |
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9 |
1 |
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9 |
1 |
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7 |
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3 |
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7 |
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3 |
7 |
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3 |
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6 |
5 |
4 |
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6 |
5 |
4 |
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6 |
5 |
4 |
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3-1/2 in. |
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(89 mm) |
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3/16 in (5 mm) |
Wiring |
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diameter, 4 places |
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Terminals |
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1
**Applies to overspeed models only.
DT9803 AND DT9804 TYPICAL WIRING
WARNING: PERFORM THE WIRING INSTALLATION WITH THE POWER SOURCE OFF. DO NOT ROUTE TACHOMETER LEADS WITH PRIMARY IGNITION WIRING.
DT9803
Connect the magnetic pickup cable conductors to the MPU terminal as shown in Figure 1. Use a two conductor shielded cable between the DT9803 and the magnetic pickup.
Figure 1: DT9803 typical wiring |
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MPU |
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Back of |
Flywheel |
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DT9803 |
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2 Conductor
Shielded Cable
Belden or Magnetic Pickup
Equivalent
DT9804
Before wiring the DT9804, determine the output voltage and ground polarity of the ignition. Table 1 lists the Peak Output Voltage and Ground Polarity of some common ignitions.
Connect the DT9804 tachometer to the CD ignition. Figure 2 shows a typical wiring diagram for negative ground ignition system.
Figure 2: DT9804 typical wiring for negative ground ignition
150-90 |
400-150 |
NEG |
Back of |
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DT9804 |
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Negative Ground Ignition |
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Optional Connection for |
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150-400 V Ignitions |
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Table 1: Output Voltage & Polarity of Common CD Ignitions
Ignition |
Ground |
Peak Output |
Use Figure |
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MFG & Series |
Polarity |
Voltage |
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Altronic I, III, & V |
Negative |
120 |
6 |
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Altronic II |
Positive |
350 |
7 |
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Bendix S-1800, BLAR |
Negative |
250 |
6 |
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Bendix Side-winder |
Positive |
300 |
7 |
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Fairbanks Morse SCSA |
Positive |
180 |
7 |
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Fairbanks Morse |
Negative |
225 |
6 |
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3000 & 9000 |
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American Bosch Magtronic |
Negative |
165 |
6 |
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DT9805 AND DT9806 TYPICAL WIRING
WARNING: PERFORM THE WIRING INSTALLATION WITH THE POWER SOURCE OFF. DO NOT ROUTE TACHOMETER LEADS WITH PRIMARY IGNITION WIRING.
DT9805
1.Connect the magnetic pickup as shown in Figure 3.
2.Connect the overspeed switch wiring as shown Figures 3 and 4. Observe the polarity of the overspeed switch. The positive terminal must be connected to the positive side of the circuit as shown.
3.If connecting to a Murphy LCDT annunciator refer to Figure 5. See General Catalog for more information on the LCDT.
Figure 3: DT9805 typical wiring for negative ground ignition
SWICHGAGE®
Back of |
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DT9805 |
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MPU |
OS |
NEG |
POS |
2 Conductor |
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Shielded Cable |
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Belden or |
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Equivalent |
To Magnetic Pickup |
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Connected to |
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307-PH-CD |
Corresponding Numbers |
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On Terminal Block Below |
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TATTLETALE® |
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4 |
5 |
Pressure |
Overspeed |
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Level |
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1 |
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2 |
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3 |
1 G 2 |
3 |
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Emergency |
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Stop Switch |
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SW |
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Frame |
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ALT 2 |
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Ground |
ALT 1 |
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GRD |
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Adapter |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
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Package |
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Connect to
Good Engine
Ground
To Negative Ground
CD Ignition
2
Figure 4: DT9805 typical wiring for positive ground ignition
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Connected to |
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307-PH-CD |
Corresponding Numbers |
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On Terminal Block Below |
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SWICHGAGE® |
TATTLETALE® |
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4 |
5 |
Pressure |
Overspeed |
Level |
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1 |
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2 |
3 |
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1 G 2 |
3 |
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Back of
DT9805
MPU |
OS |
POS |
NEG |
2 Conductor |
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Shielded Cable |
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Belden or |
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Equivalent |
To Magnetic Pickup |
Emergency
Stop Switch
SW |
Frame |
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ALT 2 |
Ground |
ALT 1 |
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GRD |
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Adapter |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
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Package |
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Connect to
Good Engine
Ground
To Positive Ground
CD Ignition
Figure 5: |
Overspeed |
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DT9805 and DT9806 |
Switch Terminals |
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on DT9805 or DT9806 |
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negative ground |
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connection to Murphy |
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LCDT (for positive ground |
NEG |
POS |
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ignitions, reverse the negative and positive wires on the tachometer so that
the positive terminal is grounded.)
Murphy LCDT |
Annunciator |
Terminal Block |
46 |
50 |