Alfred Kuhse GmbH, D-21423 Winsen/Luhe, An der Kleinbahn 39
Phone +49 (0)4171 798-0, Fax +49 (0)4171 798-117, http://www.kuhse.de
Certificated ISO 9001 since 1995
This service instruction contains information for design engineers, commissioning
and maintenance staff.
PRECAUTION HINTS
¾All applicable regulations, especially those of VDE, are to be observed.
¾A faulty connection may cause permanent damage to the unit.
APPLICATION
By means of the rapid and more accurate control
characteristics, electronic speed controllers are
more often used for speed resp. load control of
diesel and gas engines. Varying the rated value of
the speed controller can carry out a speed regula-
tion. Normally a resistor, which will be adjusted
manually or, in case of automatic gear, by means of
a servomotor, acts as the reference value transmit-
ter and supplies the governor with an analogue
signal according to the desired speed. Units, which
are used for speed control or load adjustment as
frequency controllers or active load sharing units,
transmit control pulses with a duration depending
on the control deviation.
The electronic reference value transmitter KRV
replaces the function of the motor driven rated
value potentiometer and converts the speed or load
controlling pulses into an analogue signal which
works directly the regulator; fast and accurate
control characteristics will be obtained.
The advantage of the KRV against the former used
motor driven potentiometers is mainly the possibil-
ity to adjust the reacting speed of the controlling
system continuously and the adapting can be
optimised. Furthermore the KRV works wearing
free, so that wearing faults, which occur mainly by
use of potentiometers, are excluded.
DESIGN
The KRV will be delivered in a plastic casing with
clip-on fasteners. The terminals are situated on the
front of the unit. By means of a potentiometer at the
front the maximum current limit of the control
current may be adjusted in a range of 0-20 micro
amps. At the potentiometer the sensitivity, i.e. the
reaction speed, is adjustable.
FUNCTION
After connecting the supply voltage, the green LED
ONindicates the operative condition. The drive of
the unit will be made via the following input termi-
nals and is indicated by LEDs:
Terminal 5 = decreasing speed
Terminal 6 = increasing speed
Terminal 7 = enable contact
On opening the enable contact, the reference value
current, which operates the regulator on the engine,
will be immediately set to zero. By that, the engine
runs now with the governor adjusted idle speed. If
the speed shall be modified, the enable contact must
be closed. It must remain closed permanently. By
operating the contacts DECREASING SPEED or IN-
CREASING SPEED the current will be adjusted up to
its maximum value in the negative or in the positive
range. The duration of the speed control pulse
affects the value of the current. By means of the
potentiometer SENSITIVITY the reaction time of the
engine may be adapted to the control system addi-
tionally. The controlling time depends on the ad-
justed maximum outgoing current Imax and on the
adjusted sensitivity, see diagram 1. The maximum
tolerable control current in the range of 0 to 20
micro amps. can be limited by means of the second
S165000.02-E
May 2003
Replaces: February 1996
Service Manual
Reference Value Transmitter for
Electronic Speed Controllers
Type: KRV 86.11
