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Page 8

VTX series instructions

Motor wiring

This is not so critical as battery wiring: too long

and/or too thin wire will cause a loss of maximum

current, will get hot and will waste battery power but

will not damage the controller. However, wire which

is too thick will do no harm either so we recommend

the same wire for the motor as for the battery.

Circuit breaker, fuse, isolator.

A circuit breaker or fuse may be fitted if required.

The main advantage is that it will enable the battery

or motor to be disconnected in the event of an

emergency or for security and it will give a measure

of protection should the battery be reversed.

Suggested fuse/breaker value:

50 amp max for VTX-75

25 amp max for VTX-40

Alternatively, you could fit a breaker in the battery

lead: take care not to increase the wiring length too

much. Also, certain types of breaker can have the

same effect as increased battery lead length. 

A breaker in the motor may also be useful: it will

enable you to quickly disconnect the motor in an

emergency. If correctly rated, this can also protect the

motor against overheating due to mechanical

faults.Also with the motor disconnected, free-

wheeling becomes possible. 

It is also possible to get a battery isolator switch.

These are normally fitted to lorries, buses and boats

to isolate the battery in an emergency.

Battery condition meter. 

Pins A and F (yellow and green on the diagram) are

directly connected to the battery so that you may use

them to connect a battery condition meter.

The drawing shows 4QD's LED battery indicators.

6 way connector.

The mating connector supplied is suitable only 

for

the correct size of wire.

Acceptable wire sizes are: 

 .  .  . 7 stranded 0.22-0.25mm²

 .  .  . Equivalent 24 AWG (7/32 AWG)

It is an Insulation Displacement Connector (IDC)

which 4QD have chosen because it is so very easy to

use and very dependable. - but only with the correct

wire!

Do not strip the insulation from the wires, simply

push them into the top part of the open connector and

squeeze it closed in a vice or with suitable parallel

action pliers. As you do this the tines of the contacts

bite through the insulation to make contact with the

conductors.

Wire which is too thin will not make contact. Wire

which is too thick will damage the tines.

Do not use single strand (telephone) wire: it will

make unreliable contact and easily breaks.

You can re-open a closed connector by gently

moving the tabs at the sides of the top cover outwards

to disengage the latches while lifting the cover

slightly, one side at a time.

1

1

Open

Closed

1

1

1

D red:       Max speed (7.8v approx)

E blue:     Wiper

F green:   0v (Min speed)

C black:    Reverse

A yellow: +24v  to Ignition

B white:    Ignition and reverse common.

A

B

C

D

E

F

A

B

C

D

E

F

9: Controls

Summary of Contents for VTX Series

Page 1: ...ion 4QD have a very full WWW site which has a large section giving answers to commonly asked technical questions Even if you do not have easy Internet access you will find this well worth reading so ask a friend who is connected or go to your local Internet Cafe or public library 4QD s VTX range of economy 4 quadrant controllers have been engineered to replace the NCC series As well as improved ci...

Page 2: ...4 16 Dos and Don ts p 16 Other products p 16 More information p 16 Service Guarantee p 16 The VTX series are open card controllers A very high proportion of controllers returned for repair have been damaged by mishandling Do not let any foreign body contact the board That includes water dirt screwdrivers nuts and bolts Use only fully insulated power connectors The controller can be damaged by fore...

Page 3: ...p This means that when the reversing switch is operated at speed the controller slows down under control of the deceleration ramp automatically reverses and accelerates again under control of the acceleration ramp If the ramp controls are set for quick response this process can be quite violent Also reversing is done by monitoring the demand speed after the ramp circuit and not by measuring the mo...

Page 4: ... Parking brake and Thermal Sensor are standard on VTX 75 but optional on VTX 40 A version of the controller is supplied with fixed acceleration deceleration and gain in this the presets are replaced by fixed resistors Dual Ramp Reverse Half Speed Reverse MST Preset ACC Preset DEC Preset Gain Preset RAT Preset B Connection B Connection M Connection Parking Brake Controls Expansion Connector FETs He...

Page 5: ...e heatsink However if you want to use the corner mounting holes as well you must use insulating mountings Whatever you do make sure the controller can t get wet and if it does don t connect the battery until you have dried the controller thoroughly The water won t cause damage unless the unit is connected to the battery when electrolytic corrosion will occur Overheat temperature 95 C on heatsink O...

Page 6: ...on A larger fuse can be fitted but will give less protection Use the smallest value fuse which does not cause nuisance blowing if the controller is giving more current than it can readily handle it will simply get hot See also pages 7 and 8 Motor Capacitor See page 13 Push buttons Instead of two switches ignition and forward reverse you may use two push and hold buttons Wiring is shown left note t...

Page 7: ...through the 470 ohm resistor If the battery is reversed the VTX s MOSFETs short out the capacitor so no voltage is present and the 470 ohm resistor limits the current to a safe value When the ignition switch is closed the relay coil is connected across the capacitor if there is voltage battery correct the relay operates and applies full power Wire size Use heavy duty wire for the battery and make ...

Page 8: ... fitted to lorries buses and boats to isolate the battery in an emergency Battery condition meter Pins A and F yellow and green on the diagram are directly connected to the battery so that you may use them to connect a battery condition meter The drawing shows 4QD s LED battery indicators 6 way connector The mating connector supplied is suitable only for the correct size of wire Acceptable wire si...

Page 9: ...controlled High activates Thresholds are around 5v and 7v On Off switch Circuitry in the controller switches it off zero current consumption unless there is a voltage on pin B or pin C The wiring is shown on page 6 Beware of changing any switch when the motor is running the motor will brake to a halt more or less quickly depending on the deceleration ramp setting If the switch changed is the rever...

Page 10: ... is only turning slowly then it cannot give a lot of braking so a vehicle will creep if parked on a hill To stop this you can get motors fitted with an electromagnetically operated parking brake When power is applied to this the brake is removed and when power is removed the brake is applied by a spring There are few applications where regenerative braking is deleterious and it should normally be ...

Page 11: ...es time to full speed anticlockwise decreases acceleration increases time to full speed If the acceleration is set too high anticlockwise the acceleration may be limited by the current limit which does no harm but means that acceleration is not being controlled properly so will be dependent on motor load Deceleration ramp This is shown as DEC on the diagram it is present to make the vehicle decele...

Page 12: ...to the standard 6 pin input connector if any controls are fitted to the slave then a voting system operates If either ignition is on both controllers operate If reverse is selected on one both will reverse If speed is non zero on both controllers then the fastest selected speed will control both So to avoid confusion simply plug nothing into the 6 way input connector on the slave The slave is to b...

Page 13: ... the field winding permanently across the supply and control the armature winding the shunt would motor then behaves like a permanent magnet motor Series wound motors may also be used but they cannot give dynamic braking and are very inefficient at low speeds so are not ideal To use them with the VTX series a modification must be made so the field can be correctly connected into the relay circuitr...

Page 14: ...n to base repair unless you feel confident with a soldering iron in which case ask us for help The zener can also be blown sometimes by mishandling e g disconnecting the controller than putting it down on a metal object the main capacitor stores charge for q considerable time Some problems are caused by the wrong wire in the IDC connectors MOSFETs do fail occasionally they are doing an enormous am...

Page 15: ...e can repair damaged controllers But please be sure that the controller is faulty before returning it as we may make a charge for handling controllers which are not faulty or which only have the fuse track blown There is an additional handling charge made if controllers are returned in boxes The box itself never requires and servicing Otherwise charges made will depend on the age and condition of ...

Page 16: ...ll be live as the main capacitor can store charge for several hours Drill the heatsink or do any grinding drilling or filing near the motor or controller Metal particles in motor or controller can cause failure and will immediately invalidate any guarantees Operate the controller for long if there is an evident fault It will survive a shorted motor but only for a short time Disconnect the motor le...

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