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Wiring diagram 1: electronic speed controller with BEC system
Many of the electronic speed controllers commonly used in RC model cars feature an integral BEC
system.
Caution:
These BEC systems also have load limits. As described under Wiring diagram 1, a separate
receiver battery must be used if the load is excessive (see Wiring diagram 3). Please read the
instructions supplied with the speed controller.
Example 2 of hook-up: Separate receiver battery, and three servo functions
The separate receiver battery is hooked up to a not required servo connector.
The receiver battery is hooked up through the switch cable to the battery exit of the receiver.
Receiving system
Typical wiring arrangements
Drive battery
Receiver
“Steering“ servo
To motor
Electronic speed
controller with
BEC system
4,8V receiver
battery
Switch harness
“Elevator“ servo
“Rudder“ servo
“Throttle“ servo
Receiver
Order No. 3934.1
Receiver aerial
The receiver aerial is about 100 cm long and is
attached permanently to the receiver.
The aerial should be deployed in as straight a
line as possible, and as far away as possible
from electric motors, servos, metal pushrods
and high-current leads.
In model boats the receiving system should be
installed in such a way that the receiver and the
aerial are as far away as possible from electric
drive motors, high-current cables and metal
parts.For model boats a vertical whip with a free
length of 80 - 100 cm is preferable to any other
type of aerial.Whip aerials have also proved
excellent in model cars. As an exception to the
rule, a shorter aerial may be used in a model car
since the range required is relatively short.
Installing pushrods and linkages
The basic rule is that all linkages must be
unobstructed and free-moving.
Stiff pushrods and control systems cause higher
currents to flow, thereby reducing running times
and adversely affecting
accuracy of control.It is especially important that
all servo output arms are free to move to the full
extent of their travel in both directions without
being mechanically obstructed at any point.Any
areas of the model through which pushrods pass
must be checked carefully, to ensure that they
do not foul the linkage. The same applies to hinged
components.
It is particularly important to check that the throttle
system fulfils this requirement.
The „full throttle“ setting must be determined by
the stick position, not by the mechanical end-
stop of the throttle system.
If this is not the case, the servo will be under full
load almost constantly when the model is running;
it will then draw a heavy current and may burn
out.For the same reason the idle setting must
also be defined electrically, i.e. through the stick
position, and not
mechanically through the throttle system end-
stop.
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Appendix
Supplementary notes
Suppressing electric motors
All conventional electric motors generate sparks
between commutator and brushes, and the
sparking causes interference to a greater or
lesser extent to the radio control system. For
this reason all electric motors in the model must
be effectively suppressed if the radio system is
to work properly.
In electric-powered model boats the motors must
therefore be suppressed carefully.
Suppressor filters are effective at suppressing
this type of interference, and should always be
used in any model powered by an electric motor
and controlled by radio.
Wherever feasible suppressor filters should to
fitted as close as possible to the drive motor,
and the connecting leads from the terminals to
the motor’s earth connection should be as short
as you can possibly make them (max. 20 mm).
Each electric drive motor must be suppressed
separately, with its own
suppressor filter.
Please refer to the main GRAUPNER FS
catalogue for details of suppressor
components and suppressor filters.
Minimum suppression
Order No. 3584
Order No. 3588
Motor suppression using suppressor filter
Order No. 3661 (up to 18A)
Order No. 3362 (up to 36A)
