Powerware Horsepower Computer System ST-2400S - Manual (Page 4)

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
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