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Uni Instructions
Introduction
4QD’s Uni range are Universal, Uni-directional
motor speed controllers for battery operation
covering the range of currents up to 110 amps
intermittent. Three voltage options are commonly
available: 12v, 24v and 36v. A 48v version is also
available to special order. 4QD can also supply dual
voltage versions which can be changed by shorting
out a resistor.
They are high frequency chopper drivers giving
control of motor speed both in drive mode and
braking mode. They use MOSFETs in state-of-the-
art, high frequency circuitry to give best possible
performance, reliability and battery economy.
Our drives are protected: provided you don’t actually
connect them wrongly or short them out, they will
survive almost any type of motor or misuse.
The Uni case removes easily by unscrewing the two
screws in the cover. You will need to take the cover
off if you wish to adjust the controller’s performance.
Handling
Be warned
that the main capacitors in the controller
retain charge for a long time after the battery is
disconnected. Do not therefore allow any metal
object (screwdriver, wire etc) to contact the board
when the cover is off or it may be damaged.
Motors
The Uni is a very robust controller which will work
with almost any brushed motor.
However you should always make sure the motor is
in good condition: old, dirty, worn motors will not be
reliable and can even cause controller failures.
We also suggest you fit a motor suppression
capacitor. A 10n ceramic across the motor brushes, as
close to the motor as possible, can greatly increase
system reliability. Some motors are available with
this capacitor fitted as a manufacturing option
Safety
It is normal practise, on passenger carrying vehicles,
to include some means of disconnecting the battery or
motor in an emergency. This is normally to guard
against a failure in the controller or wiring which
could cause the motor to run at an uncontrollable top
speed. The Uni range controllers are protected so that
such failure is very unlikely but the constructor
should consider what might happen in the event of
such a fault and should consider fitting an emergency
circuit breaker, relay, or battery disconnect switch or
arrange the battery so it can quickly be disconnected
in the unlikely event of a controller failure. All
passenger carrying vehicles should, in any case, be
fitted with a mechanical braking system for
emergency use.
Warning
: Never use a battery switch to turn the
controller on with the pot not at zero. This is
especially important on the 36v and 48v versions
where it can cause a resistor (beside the reverse
Polarity protection relay) to overheat. The controller
turns itself on/off automatically as the pot is
advanced/returned to zero
Battery Polarity
The Uni is polarity protected so a battery reversal
will not instantly damage anything. However be
warned that if the battery if left reversed for any
length of time, a resistor in it can be damaged.
Be warned
also that connecting any battery wire to
the motor connections could destroy the controller.
