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NCC Speed Controller

NCC series Mark 2
4 Quadrant 12v, 24v, 36v & 48v Vehicle controllers

This page is for reference only.

The NCC is no longer available. The latest equivalent is the DNO range.

NCC Mark 2 controllers build on the success of the NCC controller. The circuits of these are so well proven and successful that no major design was possible, but the board has been re-laid using sub-miniature resistors to give room for more features. Features that have changed are indicated in red.

4QD’s ‘NCC’ series are full feature Four Quadrant (acceleration and regenerative braking, forward and reverse) motor speed controllers for 12v, 24v and 36v battery operation. A 48v version is possible, for quantity orders only. The range is economical enough for toy cars, yet powerful enough for use in golf buggies so it provides a very cost-effective solution for virtually every application which requires a reversing motor controller in the current range up to 200 amps.

Some possible applications are:- Robots, invalid ‘scooters’, golf buggies, miniature railways, kiddiecars, floor cleaners, caravan shifters and vehicle loaders.

The NCC-35 is the baby of the range, covering currents up to 50 amps for short periods. For more demanding applications the NCC-70 will give currents up to 100 amps. For applications such as heavy golf buggies which use two motors, two controllers can be coupled so the two motors work as one, but with independent current limiting, giving control of currents up to 200 amps. This feature is also popular with miniature railways where two engines are ‘double headed’. All models are available in 12v or 24v versions.

The NCC series are technically advanced and packed with useful features without the ‘high tech overkill’ which is often used as a sales gimmick. The controllers have been extensively ‘value engineered’ to give the best possible ratio of performance to cost. Of special interest are the independent, linear, adjustable acceleration and deceleration ramps, the ‘dual ramp’ automatic reversing, the thermally sensitive overcurrent limiting, the regen current limit, pot fault detection, ramp down at power off, reversing at zero demand speed and automatic reverse speed reduction.

The controllers are open card, for installation in your own housing.


Supply voltage 12v, 24v, 36v, 48v depends on model more information.
Supply current 25mA (at zero speed)
Output voltage 0 to 100% full speed adjustable)
Output current NCC-35 55A (50 amps regen) Limit, typical
NCC-70 110A (100 amps regen) Limit, typical
Overheat current 20 amps typical NCC-70, current when sensor has activated
mV drop at 20 amps NCC-70 120mV typical
NCC-35 240mV typical
Switching frequency 20kHz approximately
Size 172mm x 81mm x 40mm
Weight 260g
Input 2k to 20k pot or 0-3v adjustable
Pot fault detect greater than 25k
Acceleration time 330mSec to 7 Sec adjustable
Deceleration time 330mSec to 7 Sec adjustable
MST # 0mV to 650mV Modulation Start Threshold
RAT # 0mV to 100mV Relay Activate Threshold

# MST and RAT adjustments can be ignored in most applications


* these features are fitted as standard on NCC70 but are optional extras on NCC-35.

  • High speed circuit
  • MOSFET chopper
  • Half Bridge with relays for reversing
  • Fast current limit on drive and regeneration.
  • Gain adjustment.
  • Regen braking may be turned off (on-board adjustment).
  • Electronic Ignition – Separate. Auto switch off available as an option.
  • Dual ramp Reversing may be changed to pre-select (on-board adjustment).
  • Reverse speed is half or full forward speed, selectable by on board jumper.
  • Ignition and reverse may be used with pushbuttons: one for forward, one for reverse.
  • * Electromagnetic parking brake driver connects to separate 3 pin connector.
  • Ramps on accel and decel.
  • Pot fault protection (resistance).
  • Fast current limit on drive and regeneration.
  • * Thermal shutdown (Overheat Sensor – OHS-095) at 95°C
  • Overvoltage protection.
  • Dead Band reduced (compared with Mark 1 Pro) and adjustable. (MST and RAT)
  • Motor shorted out at zero speed for maximum braking.
  • 6 pin control connector (supplied) accepts standard miniature stranded cable (7/0.2).
  • The integral heatsink will normally be bolted to a chassis which will form an additional heatsink. Normally this will be the main mounting to the machine’s chassis, or the box used to house it. The current limit reduces automatically if the controller gets hot, reducing the danger of failure. For many applications the controllers can be used without any additional heatsinking.
  • Power and motor connections are by 9.5mm tabs on the circuit side of the NCC-70 or 6.3mm tabs on the component side of the NCC-35.

Wiring Diagrams

There are several wiring diagrams available:

  • A typical wiring diagram.
  • With Dual channel Interface as used in Robots.
  • With pushbuttons for forward and reverse.


The diagram shows the features of the controllers which are assembled, fully tested and guaranteed. They are varnish coated to resist humidity and moisture.

Input is suitable for a standard 10K potentiometer. There is an on-board adjustment to alter sensitivity to suit different operating mechanisms. A connector is supplied. Various speed controls can be supplied as extras, including a spring-return-to-zero speed pot arrangement suitable for hand operation.

The circuit has fully automatic regenerative braking where most of the braking energy is returned to the battery, giving greatly extended use between recharges. With a regenerative brake the motor acts as a generator during braking. At zero speed the motor isn’t moving, so actual braking effect is zero, until the motor starts to turn. Regenerative braking can’t therefore always replace a mechanical brake since it doesn’t work well at slow speed. The circuit therefore optionally includes a driver for an electromagnetic parking brake.


You can download the instruction manual, in PDF format, via our manuals and catalogues page.