Murphy Typical Wiring, Electrical, Below is a typical wiring diagram for the ST8 Tattletale

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ELECTRICAL

The Figures below show typical customer switch wiring for the ST8. Switch wiring should be run separately from other wires; DO NOT route switch wires with AC power wires since voltages, that may be induced into the switch wires, may exceed rating and cause damage to circuits or cause false trips.

Figure 1 shows the wiring for a normally open (N.O.) SWICH- GAGE® connected between terminal B and the negative power input. A metal jumper is connected between A and B. When the SWICH- GAGE® closes the shutdown/alarm circuit will be initiated.

Figure 2 shows the wiring for a normally closed (N.C.) switch connected to input terminals A and B. The factory installed

A

A

 

B

B

Figure 1: Typical N.O.

Figure 2: Typical N.C.

Sensor Connection

Sensor Connection

metal link must be removed to use this wiring. When the switch opens the shutdown/alarm will be initiated.

Figure 3 shows the wiring for a N.O. SWICHGAGE® which is the same as Figure 1 except two wires are run from terminals A and B to the SWICHGAGE®. This Closed Loop™ wiring circuit monitors the wires as well as the switch. If the circuit is opened due to a loose connection or broken wire or the SWICHGAGE® closes, the shut- down/alarm circuit will be initiated.

Figure 4 shows the ST8 internal SPDT relay in the “run” or operat- ing mode.

 

9

10

11

 

N.O.

N.C.

C

A

 

 

 

B

 

 

 

Figure 3: Typical N.O.

Figure 4: Internal Relay

Closed Loop™ Sensor Connection

 

Circuit

 

Typical Wiring

Below is a typical wiring diagram for the ST8 TATTLETALE®.

 

 

Start

 

Flyback

Pushbutton

To Hold Coil

Diode

 

 

 

Flyback Diode

To Battery +

Starter

Flyback To Pull-in Coil Motor

Diode

Flyback

Coil

Distributor

Diode

 

 

Push/Pull Solenoid

Solenoid Valve

Slave Relay

NOTE: Connect only one shutdown device to the ST8. Wiring

for Push/Pull Solenoid, Solenoid Valve and Slave Relay shown for clarity only.

ON/OFF

2 AmpSwitch

Fuse

Battery

Engine Oil

Internal Relay

Pressure

(shown in

 

run mode)

Engine Water

ST8

Temperature

Shutdown

 

Sensor Inputs

Low

 

Water

 

Level

 

No Connection

No Connection

Differential

Pressure

9 10

11

12

13

14

Run

 

 

 

 

AA

5 1

BB

AA

6 2

BB

AA

7 3

BB

AA

8 4

BB

ON

1 2 3 4 5 6 7 8

Remove jumper from terminals 12 and 13 and set individual sensor Lockout Switch for a 25 to 35 second lockout time delay during startup (see page 4 Setting Lockout Switches).

Jumper Wire (customer supplied)

ST8

Shutdown

Sensor Inputs

No Connection

No Connection

Sensor Lockout Switches

ST-94112N page 3 of 4

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Contents General Information SpecificationsDimensions DescriptionApplying Preprinted Labels Gimbal Mount Model ST8-GPanel Mount Model ST8-F MountingTypical Wiring Below is a typical wiring diagram for the ST8 TattletaleElectrical Basic Operation Setting Lockout SwitchesTale will initiate the shutdown/alarm sequence Locate the lockout switches on back Unit see Figure