FW Murphy, 25700161, 520APH-30-24 Annunciators and Magnetic Switch, 24 VDC, Time Delay 30 Seconds
Features:
- Magnetic switches and TATTLETALE® annunciators described in this bulletin are electrically tripped relay type devices.
- CLOSED LOOP circuitry. Others draw momentary power to trip.
- All models have a weather resistant case with screw terminals for ease of customer hookup. Manually reset models have a face mounted reset push button which also serves as a fault indicator in the TATTLETALE® version. In this application, one or more TATTLETALE® / magnetic switches are used to advise operating personnel which monitored function caused shutdown. Only the
- TATTLETALE® connected to that function sensor trips causing the reset push button to pop out.
- Electrically reset models perform the same functions as the manually reset models and are reset by cycling the power supply off and then on.
- Time delay models use reliable solid state timing circuits to lockout operated switch contacts for start-up and to allow operation of alarms before shutdown occurs. Specific models allow application of power to a shutdown circuit and automatic disconnect of power after a given time delay
TATTLETALE® annunciators and Magnetic Switches are the nerve centers that translate SWICHGAGE® contact operations into decisions and operate the alarm or shutdown device. They are the electrical load carrying devices for the alarm or shutdown device. TATTLETALE® annunciators indicate which monitored function failed leading to the alarm or shutdown whereas magnetic switches do not. Magnetic switches operate basically as a latching relay.
520APH Same as 518APH except with 30 second time delay before trip on one SWICHGAGE® contact input but immediate trip on the second SWICHGAGE® contact input. Typical use is for immediate stop of engine from oil pressure or coolant temperature, but delayed shutdown from alignment switches on center pivot irrigation system. Specify 12 or 24 VDC and length of time delay.
Application:
- Magnetic Switches and TATTLETALE® annunciators for use with engines or electric motors.
- For distributor ignition engines, the magnetic switch opens the distributor coil circuit to cause shutdown. For magneto or CD ignitions the magnetic switch grounds the ignition output. Some models can also trip fuel valves instead of or in addition to grounding the ignition. Diesel engines are shut down by either closing off the fuel or air supply.
- Magnetic switches and TATTLETALE® annunciators can make or break circuits for these engines.
