Page 2
Pro-120 controller instructions
Contents
Section
Introduction
1
Safety
2
Features
3
¶ Specifications
4
Mounting
5
Connections
7
Power Connections
8
Battery wiring
8.01
Motor wiring
8.02
Circuit breaker
8.03
Battery condition meter.
8.04
Controls
9
Speed pot
9.01
¶ Use as voltage follower
9.02
Ignition (On/Off) switch
9.03
¶ High Pot lock-out
9.04
¶ Battery Discharge Protection 9.05
Reversing switch
9.06
Section
Braking
10
Parking brake
10
Adjustments
11
Gain
11.01
Full speed
11.02
Ramps
11.03
RAT and MST
11.04
¶ Expansion connector
12
Heat & Heatsinking
13
Base and cover option.
14
Waterproofing
15
Choice of motor
16
Disabling Regenerative Braking
17
Common faults
18
Fuses
18
Service & Guarantee
19
More information
21
4QD’s Pro-120 is a reversing motor speed controller
for battery operated vehicles covering currents up to
120 amps (over 150 amps peak). They are available
for operation on voltages ranging from 12v to 48v.
They are high frequency chopper drivers giving
control of motor speed both in drive mode and in
braking mode. They use MOSFETs in state-of-the-
art high frequency circuitry to give best possible
performance and battery economy. The controllers
incorporate many advanced features such as reverse
polarity protection, regenerative braking,
independent, linear, adjustable acceleration and
deceleration ramps, controlled performance at power
down, reverse speed reduction, dual ramp reversing,
pot fault protection and electromagnetic brake driver.
Many of these features can be disabled if so required.
The simplest configuration is shown in section 7.
However because of the features and versatility of
our controllers we give a lot of extra information in
this manual - which may make it seem to be more
complicated than it is so we’ve marked the more
technical sections ¶ so you may ignore them. Please
don’t be put off but read the manual quickly through
before you start. This should introduce you to what
you can do with our controllers and clarify what we
are trying to say.
Our drives are protected: provided you don’t actually
connect them wrongly or short them out, they will
survive almost any type of motor for a short time- we
regularly use a 12v starter motor as a test load,
stalling it with a monkey wrench. The drives survive
this but will get hot and therefore will eventually fail.
1
Introduction
Handling - Important!
Before handling the controller, disconnect the
batteries and short out the controller’s battery input
terminals. This will discharge the main capacitors,
which otherwise can store charge for many minutes.
If any foreign body contacts the board while these
capacitors are still charged, the controller may be
damaged.
MOSFETs tend to fail safe (i.e. open-circuit) so
failure to full speed is very unlikely. However, if the
controller is not mounted properly water might get
onto the board: no designer can make a controller
operate properly under these conditions.
The Pro has a power disconnect relay and special
sensing circuitry. If the ignition switch is switched
off at full speed then internal circuitry ramps the
2
Safety
