RechargeCar Inc. has collaborated with NetGain Motors, inc. to develop an affordable and easy to install speed sensor for their motors. Our WarP™ Speed Sensor mounts to the tail shaft of many motors to provide RPM measurements.

Knowing how fast your motor is turning is essential for an efficient and long-lasting EV. Just like internal combustion engines, electric motor efficiency changes dramatically under various operating conditions. Keeping your motor turning less than the maximum RPM (red-line) and closer to its most efficient operation will ensure your investment will last for years.

Our system does not require a magnet to be mounted to the tailshaft, but rather uses any ferrous (iron) object as a target. In addition, the lower-profile of our speed sensor allows for accessories to be mounted to the tail shaft at the same time. The sensor can be directly connected to many after-market gauges, OEM gauges and motor controllers.

installation of the wss

Click here to download the WarP™ Speed Sensor specification document, which includes installation details.

Just bolt it on and plug it in.

The stainless steel bracket attaches to the end of your motor via 2 bolts and lock washers. The angle of the bracket is adjustable over two opposing 110-degree arcs.

The sensor module is threaded along the body and mounted to the bracket with 2 nuts and a lock washer. The distance of the sensor to the target is adjustable to allow for numerous setups. We suggest that the sensor be around 1/16" away from the target. You may need to adjust this distance to get the best measurement. Note: The sensor is also available separately without the bracket and exciter ring.

The optional exciter ring can be added to the shaft of your motor to allow for after-market tachometers to function correctly. The exciter ring can accept 1, 2, or 4 targets (pulses per revolution) depending on your particular gauge.

The sensor cable is 8 feet long (2.4 meters) including the 2 foot (0.6 meter) pigtail.

As with all of our products, our WarP™ Speed sensor is designed to be modular and adaptable to suit many needs. The sensor can be connected to various after-market Tachometer gauges using the included pigtail or plugged directly into our AutoBlock RPM for more advanced features.

using the wss with an after-market tachometer gauge

You can use our WarP™ Speed Sensor with an after-market tachometer gauge to monitor the RPM of your electric motor. These gauges are available at your local auto-parts store and are designed to be be compatible with various engine types. The gauge expects to see a pulse from the vehicle's ignition system to determine the RPM of the engine. The number of pulses per revolution depends on the number of cylinders in the engine.

The WarP™ Speed Sensor can be used to simulate these pulses and drive the after-market tachometer gauge by using our optional exciter ring. This ring is made from aluminum with steel set screws acting as targets for the sensor. By adding or removing some set screws, you can produce 1, 2 or 4 pulses per revolution (3 even pulses can be achieved with some user modification of the exciter ring), depending on what your system requires. Set your gauges to monitor the number of cylinders equal to twice the number of pulses per revolution. For example, use 8 cylinders if you have 4 set screws (4 pulses) on your exciter ring.

We provide a pigtail to allow you to connect your gauge to the sensor module. There are 3 wires in the pigtail: Red = +12volts, Black = GND, Green = Signal.

about the sensor module

Our Hall Effect sensor module is an open-collector sinking type consisting of a sensor, magnet and amplifier. As a ferrous object passes by the sensor, the magnetic field changes and the output voltage changes. The output signal is pulled up to the source voltage (12 volts) via a 2.2K ohm resistor.

The sensor housing is made from anodized aluminum and meets IP67 for dust and water protection.

Check out the Wikipedia link to learn how Hall effect sensors work: http://en.wikipedia.org/wiki/Hall_effect_sensor


Our WarP™ Speed Sensor is designed to be compatible with the most popular motors made by NetGain Motors, including most WarP™, ImPulse™, and TransWarP™ motors. Check for the two 1/4"-20 tapped holes near the tail end of your motor. This is where the sensor bracket mounts.

To be sure, measure the diameter of the tail shaft before ordering

    When ordering:

  • Choose 0.875" exciter ring for WarP™ 8, WarP™ 9(old version), WarP™ 11(old version), and ImPulse™ 9 motors

  • Choose '0.875" exciter ring for Zilla controllers' if you plan to connect your sensor directly to your Zilla motor controller. The Zilla requires a more specific input pulse width, and this exciter ring will provide that.

  • Choose 1.125" exciter ring for WarP™ 13, TransWarP™ 7, TransWarP™ 9, TransWarP™ 11 motors, Warp 9(new), Warp 11(new)

  • WarP™ Speed Sensor is available NOW. Feel free to Contact Us with questions.