Powerware ST-2400S User Manual

Model ST-2400S

Horsepower Computer System

User Manual

In the USA:

Star Test Dynamometer, Inc.

712 Thistlewood Court

Normal, IL 61761

Phone: [phone]

In Mexico, Central & South America:

Negociaciones Fuentes S.A. DE CV

Av. La Luz 4549 Col. Cortijo del Rio

Monterey, N.L. Mexico 64890

Phone: [phone]

Manufacturered by:

Ries Labs, Inc.

2275 Raven Road

Farina, IL 62838

Phone: [phone]

eMail: [e-mail]

Table of Contents

Description ---------------------------------------------------------------- 3

Installation ---------------------------------------------------------------- 3

Power Supply --------------------------------------------------------- 4

Operation of the unit from 220-260 VAC 50-60 Hz ----------- 4

Operation ------------------------------------------------------------------ 4

Computer Function Switch ---------------------------------------- 5

System Power LED -------------------------------------------------- 6

Torque Set Switch --------------------------------------------------- 6

Printer/Computer Interface --------------------------------------- 7

Computer Software for the 2400S horsepower computer --- 8

Calibration Software for the 2400S ----------------------- 8

Dyno32 Software ---------------------------------------------- 8

DynoGraph Software ---------------------------------------- 9

Calibration ------------------------------------------------------------- 9

Calibration Procedures ------------------------------------- 10

Calibration Procedure Notes ------------------------------ 11

Torque Calibration Notes --------------------------------- 12

In case of Difficulty ----------------------------------------------------- 14

2

Description:

The function of the Model 2400S Horsepower Computer is to provide the operator with a
continuous digital readout of the RPM, TORQUE, POWER (Horsepower or Kilowatts)
and percentage of Torque Rise ( % TORQUE RISE) when properly attached to a
compatible dynamometer.

The RPM readout shows the operator the rotation speed (rotations per minute) of the
power shaft of the dynamometer. The RPM is measured by a pickup and gear
combination that is mounted on the dynamometer and coupled to the power shaft of the
dynamometer.

The TORQUE readout shows the operator the torque (Foot-Pounds or Newton-Meters)
being produced by the prime mover being tested. This is the same as the torque applied
to the dynamometer by the power source (motor, engine, drive wheels, etc.). The torque
is measured by a load cell that is mounted on the dynamometer.

The POWER readout shows the operator the amount of power being produced by the
prime mover and applied to the dynamometer. This is the same as the power being
absorbed by the dynamometer. It is computed by the Horsepower Computer using the
RPM and Torque measurements using the formulae below:

HORSEPOWER = ( RPM * TORQUE (foot-pounds) ) / 5252

KILOWATTS = ( RPM * TORQUE (Newton-Meters)) / 9549

The % Torque Rise (% Torque Load) meter shows the torque as a percentage compared
to a reference torque value. It is used to measure the “lugging ability” of an engine.

The Horsepower Computer has a RS-232 compatible serial interface which can be
connected EITHER to compatible serial printer OR to an external computer system.
When connected to a printer, the system may be used to provide a “hard copy” printout of
measurement results. When connected to an external computer, the system may be used
for printing, storing, graphing, (etc.) the measurements performed by the dynamometer
system (including the dynamometer, horsepower computer, and external computer).

Installation:

The Model 2400S horsepower computer should be installed in a location where the unit is
not exposed to wetness, extremely high temperatures, prolonged direct sunlight, or other

environmental factors that would shorten the life expectancy of the unit

.

3

Power Supply:

The Model 2400S horsepower computer is normally operated from 110 to 125
VAC (60 Hz) using the outlet mounted power supply that is supplied with the
unit. The power consumption of the computer is very low and the unit has a very
high tolerance for power supply variations, so nearly any standard 115 VAC
utility power outlet should power the unit adequately. See (below) information on
a special (optional) “wide-range” power supply which will power the unit
properly when the line voltage is either very low or very high.

The computer may also be operated from a source of 12 to 18 Volts DC such as a
small DC power supply or 12 Volt storage battery. If a storage battery is used, be
sure that it is properly charged. If the battery voltage is low, the POWER LED of
the unit will flash “on” and “off” about once every second – indicating that the
power supply voltage is inadequate to power the unit properly. NOTE: WHEN

OPERATING THE UNIT FROM A BATTERY OR POWER SUPPLY,
THE POLARITY (+/- WIRING) MUST BE CORRECT OR THE UNIT
WILL NOT OPERATE. WIRING A BATTERY OR POWER SUPPLY TO
THE UNIT WITH IMPROPER POLARITY MAY RESULT IN DAMAGE
TO THE UNIT.

Operation of the unit from a 110 to 250 VAC 50 to 60 Hz power source

A special “universal input” power supply is available (as an option) which will
allow the unit to be operated from a wide range of AC power sources – both
domestic and international.

This power supply has a detachable power cable which may be easily replaced
with a power cable which matches the local power system.

This power supply is also very useful when operating the unit from power
sources which may be lower than standard and/or slightly erratic. This
power supply will result in proper operation when the AC power source is a
low as about 90 Volts AC.

Operation:

The horsepower computer normally operates with a two second measurement
cycle. It can optionally be factory programmed for a one second measurement
cycle. During the measurement cycle, the RPM of the dynamometer shaft is
measured along with the torque sensed by the dynamometer load cell. At the end
of each measurement cycle, the RPM and TORQUE values (averaged over the
measurement interval) are displayed and the POWER and % TORQUE RISE

4

values are computed and displayed. This process is repeated continuously while
the unit is in operation.

Computer Function Switch:

The computer function switch is used to turn the system power ON/OFF
and to control the functional operation of the horsepower computer. The
function switch has four positions ( “OFF”, “ZERO”, “CHECK”, and
“RUN”).

In the “OFF” position, the power to the horsepower computer (and the
load cell, etc.) is turned “OFF”. The power is turned “ON” in the other
three positions of the computer function switch.

The horsepower computer has two user controllable self test modes
(“ZERO” and “CHECK”). These can be used to test much of the
horsepower computer’s internal circuits for proper operation. In the
ZERO position, internal test signals are fed into the RPM and TORQUE
measurement circuits. In the ZERO position of the function switch, these
signals should result in readings of zero on all four displays. If the reading
of any display remains substantially different from zero (more than +/- 1
or 2 counts) when in the zero mode, some type of malfunction of the unit
is indicated.

The second user controllable test mode is the CHECK mode. In this
mode, internal test signals are fed to the RPM and TORQUE measuring
circuits to simulate normal operation of the unit at about 37.5 % of full
scale torque. The actual readings shown on the displays of the unit depend
on internal factory set optional settings – principally the full scale torque
value (which corresponds to the size of the load cell being used with the
unit). The RPM display should read about 4000 RPM (+/- 1 or 2 counts)
on all units. The Torque display should read about 37.5 % of the load cell
rating. Refer to the tables below for the proper readings of the Torque and
Power displays for your unit. The Power reading should agree with the
power you compute from the actual RPM and TORQUE readings (within
+/- 1 or 2 counts) using the above formulae for the horsepower or
kilowatts.

Load Cell Rating (Ft.-Lbs.) Torque (Ft.-Lbs.) Power (HP)
100 37.50 28.56
200 75.00 57.10
500 187.5 142.8
1,000 375.0 285.6
2,000 750.0 571.0
5,000 1875 1428

5

10,000 3750 2856

CHECK readings using Ft.-Lbs. & Horsepower

6