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Page 4

VTX series instructions

5: Features

The diagram above shows the VTX-75 which has

four MOSFETs and capacitors. The VTX-40 has two

only. Otherwise, the VTX-40 is largely the same as

the VTX-75.

Speed pot and reversing switch input is via a 6 pin

connector, supplied.

Power & Motor connections are by 6.3mm blade

connectors on top of the board. Spare power

connections are provided and can be used for control

wires or for extra motor wires as you wish. 

Also available is an expansion connector option, see

page 12.

Regen brake defeat option, RAT and MST presets are

not normally fitted but are replaced by fixed resistors.

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

Heatsink

Forward

Relay

Relay

Reverse

Thermal Sensor

Capacitors

A

B

C

D

E

F

A

B

C

D

E

F

159mm

88mm

89mm

25.4

Supply voltage

12v, 24v, 36v or 48v 

different models.

Supply current

25mA

at zero speed

Motor speed

forward

0 to 100% full speed

adjustable

reverse

0 to 50%/100% full speed

selectable

Output current

VTX-40

40A approx 1 minute

55A limit, typical

  (typical)

VTX-75

75A approx 1 minute

110A limit, typical

6: Specifications

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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