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4QD-300 Issue 5 Manual
Most faults are caused by problems in the external
wiring.The controller has many safeguards to restrict
damage if there is a problem and an understanding of
the safeguards should assist in finding faults.
All voltage measurements should be made with meter
negative on the battery negative terminal.
The ignition switch applies battery voltage to pin 3 of
the 4 way connector. This enables the controller's
internal power supply. Until the internal supply is on
the controller is dead. The internal supply (+12v) can
be measured on pin 2 of the 6 way connector.
+12v is also applied (via pot fault detection circuitry)
to the top of the throttle pot, pin 4, where you should
measure around 11.4 volts.
As the throttle pot is moved it applies a variable
voltage back to pin 5 of the 6 way connector. But
there is a 'high pedal lockout' circuitry which
prevents the controller taking off at high speed if the
throttle is faulty: this resets itself when the voltage on
pin 5 falls to zero.
So check that the throttle voltage varies from 0v
upwards. The top voltage may be 11.4 or less (the
gain can be adjusted to compensate) but never more
than 11.4v. This does not apply to the uncommon
Joystick mode where 'zero speed' is about 5.5v.
If the 12v is correct and the pot voltage is altering
from zero upwards there is a fault in the controller.
Most faults in the controller will need attention at the
factory as they require instruments and experience of
such high current circuitry which are not usually
available to electronic repair shops.
Loss of power
Most models include battery discharge protection
which cuts back the power when the voltage in the
controller drops too low. Unfortunately this cannot
tell the difference between a flat battery and a poor
connection of a bad wire. If the battery wires are too
long and thin they will drop voltage - and this may
result in a dramatic loss of power as the protection
cuts in.
This feature may then require the use of thicker
battery wire
Other faults
See our www site! There is a large service section.
18
Fault finding
17
Fuse
A fuse track is present on the controller: it is on the
base board (beneath the 6 way connector of the top
board) and is arrowed on the 'Features' diagram. It is
provided to limit damage to the controller in the
event of a fault in the external wiring. It is in the
+24v line which feeds to to pin 4 of the 4 way
connector (ignition and meter) and to pin 3 of the 3
way connector (brake solenoid).
This fuse does not protect any of the controller's
electronics, nor can it be blown by any fault in the
controller. If it blows, the ignition will be off and the
controller will be dead.
If this blows, first find and repair the cause of the
fusing.
Two empty fuse clips are provided on the board
where a standard 20mm fuse (1.0 amp) may be tted
if the track blows. These are between the two boards
and the Features diagram has a section of the top
board 'cut away' to show their position.
Controllers returned for repair with
only
this track
blown will be subject to a charge for handling, test
and carriage.
See us via the Internet: http://www.4QD.co.uk Email to: support@4QD.co.uk
We're in Control
We're in Control
Office
30 Reach Road
Burwell
Cambridgeshire, CB5 0AH
Fax: 01638 744 080
Stores
Unit 6A
Heath Road Industrial Estate
Burwell
Cambridgeshire, CB5 0AP
4
Q
D
1
Foreword
We have tried to make this manual as readable as we
can. We hope you will read it through before you
start trying to install 4QDs motor controllers. Even if
you dont understand everything to start with, reading
it will make you familiar with what we are trying to
say and do. We welcome feedback so if anything is
unclear, please let us know.
This manual describes our standard range of
controllers. Many options are available, so if there are
points you want clarified, or features or specifications
you want altered, please consult the factory.
In the section Features and Glossary we have also
discussed the controllers features, some of the
controls you may wish to fit and the type of
information you may need to make a choice of
controller.
To help to avoid confusion, certain paragraphs are
marked with a bullet �. These are more technical and
may be omitted by the less technical reader.
2
Introduction
This manual covers the 4QD-300 series of heavy duty
controllers (up to 300A) for 24v, 36v and 48v battery
operated motors. The controllers are fully electronic
giving control of the motor in all four quadrants -
that is forward and reverse, acceleration and braking -
so they use no relays or mechanical switches,
increasing reliability. All internal connections and
wiring are rated to carry full current so the controller
continuous ratings are only limited by external heat
dissipation. Moreover the substantial built-in heatsink
is designed so that additional heat sinking can be
added in the unlikely event it is required.
The controllers use state-of-the-art MOSFET power
transistors which are chopped on and off very
rapidly to give ultra-smooth speed control with
minimum losses for best control with minimum
heating in controller, motor and wiring.
During braking a large proportion of the braking
energy is returned to the battery, helping to reduce
battery drain and extend the time between charges.
Power connections are by substantial M8 screw
terminals.
Instruction Manual
4QD series controllers
4QD-300-36 and 4QD-300-48
Issue 08 control board.
29th April 2003
See us via the Internet: http://www.4QD.co.uk Email to: support@4QD.co.uk
We're in Control
We're in Control
Office
30 Reach Road
Burwell
Cambridgeshire, CB5 0AH
Fax: 01638 744 080
Stores
Unit 6A
Heath Road Industrial Estate
Burwell
Cambridgeshire, CB5 0AP
4
Q
D Page 2
4QD series controller instructions.
3
Contents
1
Foreword
2
Introduction
3
Contents
4
Dos and Donts
5
Specifications
6
Features
7
Controls
8
Adjustments
Gain
Ramps
� Current
� Reverse Acceptance Threshold
� Reverse Speed
9
Wiring
10
Power connections
Battery & motor wire size
Battery wiring
� Reverse polarity protection
� Circuit breaker or fuse.
Motor wiring
Motor polarity
Using several motors
11
Control wiring
Pre-wired models
Connectors
6 way connector
4 way connector
3 way connector
12
Wiring - various
Ignition switch
Battery meter
Ignition light
Speed control pot
Reverse switch
� Top Speed adjustment
� Brake solenoid
� Inhibit input
Hand control box
13
Output current & Heatsink
14
Mounting & Earthing
15
Waterproofing
16
Battery charging
17
Fuse
18
Fault finding
4
Dos and Donts
Do
Keep the controller covered at all times
- or water, dust and dirt will enter.
Fit reverse polarity protection
- if theres any chance of someone connecting the battery wrongly
Make sure terminal nuts are tight
- current through a loose connection will burn it.
Keep the motor in good condition.
Damaged brushgear and commutators can blow the controller.
Fit a motor suppression capacitor
. A 10n ceramic across the motor brushes, as close to the motor as
possible, can greatly increase system reliability.
Do not
Drill or otherwise modify the metal base
- its impossible to keep metal swarf out of the controller. This
WILL blow the controller!
Test the controller without securing the top board in place
: as a bare minimum, loosely insert the two
screws at the end away from the 6 way connector.
Hard-wire the ignition:
this is also a reset switch if the controller trips for any reason!
Additional Information
Although this manual is quite comprehensive, there is a limit to what it is sensible to print on paper. If you
have queries, then you are best advised to consult our www site where there is a large amount of additional
information including many instructions on some of the more arcane applications of this controller
Page 15
4QD series controller instructions.
Most water problems are caused by condensation or
by splashing. The 4QD controllers circuit boards are
coated with a water resisting varnish so condensation
is not a problem, especially as the controller will
warm slightly in use, expelling any condensation.
However water splashes must be kept away from the
electronics and we at 4QD have taken great care to
make sure this is done.
The vacuum formed cover of the controller is
waterproof and will keep off water from above. The
mouths of the controller (one each end) are sealed
with a piece of waterproof foam between board and
base (F in the above diagram of the 4QD-200)
Behind the terminals is a plastic splash plate (SP in
diagram). A notch is present in this for control wires
to pass through. For proper splash proofing this plate
should be sealed to the board using Dow Corning 734
RTV - a free flowing silicone rubber with a
consistency like treacle. Do not use ordinary si rubber
- it won't do a good job and is very messy!
To use the silicone, remove the splash plate and wire
the controller. Now, with the controller base plate
horizontal and at the bottom. run a small bead of the
silicone along the bottom (longest edge) of the splash
plate before re-fitting it. The silicone will run down
the plate and seal it to the board. Use the top cover to
hold the