■
Normally Open and Normally Closed Overspeed
Alarm or Shutdown Switch
(Standard)
■
RPM Data and Power Supplied by Magnetic
Pickup or Capacitor Discharge (CD) Ignition
■
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
SHD30 and SHD30-45 Models
Description
The SHD30 and SHD30-45 are microprocessor-
based tachometers with hourmeter and an over-
speed 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 over-
speed.
The SHD30 features a panel-mounting design, plas-
tic enclosure that is 5-1/16 (129 mm) long and
4-1/4 in. (108 mm) high.
The SHD30-45 has the same enclosure, but it also
has a backplate with studs to mount like a SHD-
45, OPLFC.
The SHD30 models power and RPM data are
supplied by 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.
Basic Operation
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 dis-
played 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.
Applications
Easy-to-Calibrate
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.
Specifications
Power input:
CD ignition:
90 to 350 VDC.
150 µA typical @ 90 VDC;
300 µA @ 350 VDC.
Magnetic Pickup:
5 to 120 Vrms.
325 µA typical @ 5 Vrms, 100 Hz;
450 µA 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, 3 V, 220 mAh power. Shelf life
expectancy 10 years.
Operating Temperature:
-4° to 158°F (-20° to 70°C).
Storage Temperature:
-40° to 300°F (-40° to 150°C).
Case Material:
Plastic.
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:
0.5 A, 350 VDC continuous.
Connected to Form “C” Relay terminals:
Relay Contact, 0.5 A, 30 VDC, 125 VAC resistive.
Tachometer Accuracy:
±0.5% of the display
reading or ±1 RPM whichever is greater.
Hourmeter Range:
0 to 65535 hrs.
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 in.
(235 x 210 x 133 mm).
•
Gas Compressors
•
Oil Field Equipment
•
Industrial Engines
•
Generators
When installed per Murphy Drawing 20-08-0258
C US
SHD3-97050B
Revised 07-04
Replaces SHD-95064B
Catalog Section 20
(00-02-0287)
Digital Tachometer and Hourmeter
with Adjustable Overspeed Trip Point
