The Murphy Digital Tachometer and Hourmeter with Adjustable Overspeed Trip Point SHD30 is a microprocessor-based tachometer with hourmeter and an overspeed trip point. The trip point can be connected as either a form "c" relay output or as a normally open SCR output for alarm or shutdown on overspeed. The SHD30 features a panel-mounting design, plastic enclosure that is 5-1/16 in. (129 mm) long and 4-1/4 in. (108 mm) high. The SHD30 receives power and RPM data from either a magnetic pickup or a capacitor discharge (CD) ignition. The hourmeter is adjustable to a preset time and resettable to zero. Should power be lost, on-board batteries maintain the run hours display and allow for resetting the overspeed relay output.
When a tach signal is present the SHD30 models display rpm. When a tach signal is not present, the display is blank unless the Read Hours membrane key, on the faceplate is pressed and held. The five-digit, liquid crystal display is updated every second. The run hours, overspeed set point and current pulses per engine revolution can be displayed by manipulating the membrane switches. Run hours can be displayed even after power is lost. The run hours display can be configured to alternate with the RPM display.
The SHD30 models calibration is done by enter- ing the number of pulses per engine revolution using the Pulses per Revolution and Overspeed Setpoint membrane keys, on the faceplate. The number of pulses is determined by the number of cylinders, cycles and ignition features. It is also determined by the number of ring gear teeth of the engine’s flywheel on a magnetic pickup sys- tem.
Presetting and resetting running hours is done from the back and front of the SHD30 models.
- Accurate to ±0.5% of Display Reading
- Hours Can Be Preset and Reset to Zero
- Approved for Class I, Division 2, Groups C & D Hazardous Areas
- Normally Open and Normally Closed Overspeed Alarm or Shutdown Switch (Standard)
- RPM Data and Power Supplied by Magnetic Pickup or Capacitor Discharge (CD) Ignition
- Part No.: SHD30
- Case Material: Plastic
- Power input: CD Ignition 90 to 350 VDC. 150 A typical @ 90 VDC; 300 A @ 350 VDC
- Magnetic Pickups: 5 to 120 Vrms. 325 A typical @ 5 Vrms, 100 Hz; 450 A typical @ 5 Vrms, 1 kHz; 1 mA typical @ 5 Vrms, 5 kHz; 2 mA typical @ 5 Vrms, 10 kHz; 15 mW max. @ 5 Vrms, 10 kHz; 2.8 W max. @ 120 Vrms, 10 kHz
- Backup Batteries: 2 replaceable, long-life Lithium batteries, Panasonic CR2032 or equivalent, 3V, 220 mAh power. Shelf life expectancy 10 years
- Operating Temp: 4° to 158°F (-20° to 70°C)
- Storage Temp: -40° to 300°F (-40° to 150°C)
- Ignition Frequency Range: 3 to 666 Hz
- Magnetic Pickup Frequency Range: 1 to 10 kHz
- Overspeed Output: Connected to S.C.R. (Silicon Controlled Rectifier) terminals; 0.5A, 350 VDC continuous. Connected to Form "C" Relay terminals: Relay Contact, 0.5A, 30 VDC, 125 VAC resistive
- Tachometer Accuracy: +/- 0.5% of the display reading or +/- 1 RPM, whichever is greater
- Hourmeter Range: 0 to 65,535 hours
- Hourmeter Accuracy: +/- 15 minutes per year
- Laboratory Approvals: CSA (Canadian Standards Association) approved for Class I, Division 2, Groups C & D hazardous areas
- Shipping Weight: 1 lb (0.5 kg)
- Shipping Dimensions: 9-1/4 x 8-1/4 x 5-1/4 inches (235 x 210 x 133 mm)